The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to...The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to provide ideas for this issue.This strategy relied on using appropriate mechanical treatment and sodium lignosulfonate coating to improve the dispersion and interfacial compatibility of bamboo fibers in poly(lactic acid).By optimising the particle size and concentration of sodium lignosulphonate,high value-added and green composites were prepared using sectional pressurization with a venting procedure.The treated composite displayed an ultra-smooth surface(roughness of 0.592 nm),impressive transient properties(disintegration and degradation behaviour after 30 d),and outstanding ultraviolet(UV)shielding properties(100%).These properties hold the promise of being an excellent substrate for electronic devices,especially for high-precision processing,transient electronics,and UV damage prevention.The satisfactory interfacial compatibility of the composites was confirmed by detailed characterisation regarding the related physicochemical properties.This investigation offers a sustainable approach for producing high value-added green composites from biomass and biomass-derived materials.展开更多
This article provided a preparation protocol for poly(lactic acid)(PLA)/modified epoxidized soybean oil(ECP)/nano-magnesium oxide(n-MgO)ternary composites and studied their mechanical and antibacterial properties.By m...This article provided a preparation protocol for poly(lactic acid)(PLA)/modified epoxidized soybean oil(ECP)/nano-magnesium oxide(n-MgO)ternary composites and studied their mechanical and antibacterial properties.By means of an organic synthesis technique,epoxidized soybean oil(ESO)is chemically grafted to PLA to synthesize ESO chemically plastically modified PLA,abbreviated ECP.To fabricate PLA/ECP/n-MgO composite materials,ECP acts as a plasticizer and a compatibilizer simultaneously,and n-MgO acts as an enhancer.Then scanning electron microscopy,X-ray diffraction,differential scanning calorimetry,universal tester,and antibacterial research were exploited to characterize the morphology,thermal resistance,mechanical properties,and antibacterial performance of PLA/ECP/n-MgO composites.The experimental results show that ECP acts as a plasticizer by causing heterogeneous nucleation,which increases PLA's crystallinity.Evenly distributed n-MgO can greatly improve PLA's antibacterial qualities.Furthermore,ECP and n-MgO work together to improve the positive aspects of PLA/ECP/n-MgO composites,with PLA/ECP/n-MgO 100/1/0.5 composites having the best overall properties.While improving the mechanical performance and toughness of PLA,this work offers a prospective approach and foundational database for the creation of multifunctional biodegradable composites.展开更多
To retain its inherent biodegradability,simultaneously improving the strength and toughness of poly(lactic acid)(PLA)is a significant challenge.In this study,we propose an innovative multiple dynamic pressure(MDP)proc...To retain its inherent biodegradability,simultaneously improving the strength and toughness of poly(lactic acid)(PLA)is a significant challenge.In this study,we propose an innovative multiple dynamic pressure(MDP)process that can produce pure PLA with excellent mechanical properties.The MDP process generates a dynamic stretching effect by regulating the application and release of pressure,prompting disordered molecular chains to be arranged regularly along the direction of the dynamic force field.This promoted the formation of more ordered crystal forms(α-form)and strengthened the connection between the crystalline and amorphous regions.Results show that after MDP treatment,the tensile strength and strain at break of MDP-PLA are significantly improved,reaching 91.6 MPa and 80.1%respectively,which are 49.4%higher and 10 times higher than those of the samples before treatment.The mechanical properties of MDP-PLA can be regulated as needed by adjusting the cycle times and peak pressure.In addition,through a systematic study of the structural evolution of MDP-PLA,the performance regulation mechanism of the MDP process was thoroughly investigated,and the internal relationship among the process-structure-performance was clarified.This research not only opens a new technical path for the preparation of high-performance pure PLA but also provides important guidance for the high-performance modification of other semi-crystalline polymers,thus possessing significant scientific and engineering value.展开更多
The continuous improvement in patient care and recovery is driving the development of innovative materials for medical applications.Medical sutures,essential for securing implants and closing deep wounds,have evolved ...The continuous improvement in patient care and recovery is driving the development of innovative materials for medical applications.Medical sutures,essential for securing implants and closing deep wounds,have evolved to incorporate smart materials capable of responding to various stimuli.This study explores the potential of thermoresponsive sutures,made from shape memory materials,that contract upon heating to bring loose stitches closer together,promoting optimal wound closure.We developed nanocomposites based on a blend of poly(lactic acid)(PLA)and thermoplastic polyurethane(TPU)—biopolymers that inherently exhibit shape memory—enhanced with carbon nanotubes(CNT)and graphene nanoplatelets(GN)to improve mechanical performance.PLA/TPU(50/50)nanocomposites were prepared with 1 and 2 wt%GN,as well as hybrid formulations combining 1 wt%CNT with 1 or 2 wt%GN,using a twin-screw extrusion process to form filaments.These filaments were characterized through differential scanning calorimetry(DSC),field emission gun scanning electron microscopy(FEG-SEM),tensile testing,and shape memory assessments.While the PLA/TPU blend is immiscible,TPU enhances the crystallinity(X_(c))of the PLA phase,further increased by the addition of CNT and GN.FEG-SEM images indicate CNTs primarily in the PLA phase and GN in the TPU phase.PLA/TPU with 1 or 2 wt%GN showed the highest potential for suture applications,with a high elastic modulus(~1000 MPa),significant strain at break(~10%),and effective shape recovery(~20%at 55℃ for 30 min).These findings suggest that these nanocomposites can enhance suture performance with controlled shape recovery that is suitable for medical use.展开更多
Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA s...Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA still poses potential environmental pollution risks after being discarded.The efficient chemical recycling of PLA represents an attractive approach to addressing both resource reuse and environmental pollution challenges caused by its waste.Hydrolysis is the predominant method of industrial recycling.However,because PLA is insoluble in water,efficient heterogeneous hydrolysis requires high-temperature and high-pressure conditions.In this study,an efficient homogenous hydrolysis method capable of simultaneously dissolving PLA and calcium hydroxide(Ca(OH)_(2))was developed.Suitable solvents for this method were screened,and it was found that PLA hydrolysis using dioxane and 1,4,7,10,13-Pen-taoxacyclopentadecane as solvents achieved conversion rates of 93%and 90%,respectively,within 2 h at room temperature.Notably,the hydrolysis product,calcium lactate,precipitated as a solid from the solvent and therefore self-separated from the reaction solution.The solvent,acid/base conditions,water content,and depolymerization kinetics were investigated.Compared with previously reported hydrolysis methods,the enhanced efficiency observed in this study can be attributed to the concurrent solvation of PLA and Ca(OH)_(2),which maintains homogeneity throughout the reaction process.Additionally,this method facilitates closed-loop recycling of PLA and is compatible with the highly selective recovery of PLA from various types of PLA products.展开更多
AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mes...AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.展开更多
Lactic acid bacteria(LAB)exopolysaccharides(EPS)reveal high safety and multiple activities,and are typical postbiotics produced by LAB during fermentation.In this paper,6583 articles on LAB-EPS from Web of Science and...Lactic acid bacteria(LAB)exopolysaccharides(EPS)reveal high safety and multiple activities,and are typical postbiotics produced by LAB during fermentation.In this paper,6583 articles on LAB-EPS from Web of Science and Elsevier databases were retrieved,and 236 articles related to this review were screened.The EPS from 90 LAB strains were summarized in terms of their extraction methods,yield,molecular weight,monosaccharide composition,glycosidic bond configuration and the structural and activity relationships(SARs).However,there exist great challenges as for the low yield and high cost in EPS production.Therefore,this review further elaborated the mechanism of EPS secretion,the anabolic pathway of EPS,the structure and mechanism of key enzymes involving in EPS synthesis process,the prospect of gene regulation for EPS secretion,and proposed the engineering strategies for increasing EPS yield or tailored EPS design in recent years.In addition,CRISPR/Cas9 gene editing technology was also discussed in the production control of EPS in LAB.Finally,the engineering strategy of increasing EPS yield in recent years was proposed.This work might provide important theoretical support for the production and application of LAB-based EPS.展开更多
Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport ...Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport while maintaining the structural stability of the electrode under continuous charge‑discharge cycles.Electrochemical characterization under a three‑electrode system revealed exceptional rate capability:Mn@PN delivered an ultrahigh specific capacitance of 10318 F·g^(-1) at a low current density of 3 A·g^(-1) and retained 9415 F·g^(-1)(91.2%retention compared to the value at 3 A·g^(-1))even at an ultrahigh current density of 50 A·g^(-1).Moreover,the material exhibited 97.4%capacitance retention after 9000 cycles at 30 A·g^(-1),corresponding with a low capacitance decay rate of 0.003‰per cycle,significantly outperforming conventional conductive polymers like polyaniline(PANI).An asymmetric supercapacitor assembled with Mn@PN as the positive electrode(Mn@PN||AC)achieved an energy density of 328 Wh·kg^(-1) at 15 A·g^(-1) and retained 80.7%of its initial specific capacitance after 4000 cycles at 20 A·g^(-1).展开更多
BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis ...BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis and heart failure has rarely been observed in cases of pediatric patients with CH pathology.Here,we explored the etiological relationship between CH,heart failure,and refractory lactic acidosis to reflect the importance of thyroid function screening in neonates with heart disease.CASE SUMMARY A 33-day-old extremely premature female infant presented with tachypnea,respiratory distress,recurrent infections,and abdominal distension postnatal.On admission to our facility,she had cardiomegaly,hepatomegaly,and lactic acidosis(revealed on blood gas analysis),with lactate progressively rising to 25 mmol/L.Chest radiographs showed pulmonary congestion,while echocardiography revealed cardiac enlargement,left ventricular wall thickening,and pericardial effusion.Initial management aimed at correcting acidosis and treating heart failure proved ineffective.After reassessment,thyroid function tests showed significantly decreased triiodothyronine,free triiodothyronine,thyroxine,and free thyroxine levels,with a significantly increased thyroidstimulating hormone level,confirming a CH diagnosis.Levothyroxine was administered,resulting in rapid correction of lactic acidosis and gradual improvement of thyroid function and systemic symptoms,culminating in full recovery and discharge.We also reviewed the relevant literature on thyroid and cardiac dysfunctions in order to explore their deeper association.CONCLUSION This case links CH-induced heart failure with refractory lactic acidosis,urging prompt thyroid screening in affected neonates to reduce mortality.展开更多
Conductive polymers have recently drawn tremendous attention due to their promising applications in electronic and energy-related devices.While p-type conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(...Conductive polymers have recently drawn tremendous attention due to their promising applications in electronic and energy-related devices.While p-type conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)have achieved commercialization,the development of stable,high-performance n-type polymers has lagged.Recently,the discovery of n-type polymer poly(benzodifurandione)(PBFDO)has greatly promoted the development and application of n-type conductive polymers.However,the synthesis process involves cumbersome post-processing,which greatly increases the cost and difficulty of mass production.Herein,a novel synthesis method for PBFDO has been developed,which was promoted by the combination of solvent dimethyl sulfoxide(DMSO)and acetic anhydride(Ac_(2)O).This method exploits the oxidative capability of DMSO,activated by Ac_(2)O,which can promote the keto-enol tautomerism of 3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione(BFDO)and induce the rapid polymerization.The resulting PBFDO ink exhibits a high electronic conductivity of more than 2000 S cm^(-1)and excellent ambient stability.Significantly,the additives and by-products remain in a liquid state during the polymerization process and possess low boiling points,allowing for the production of pure PBFDO films through straightforward heating and drying.Furthermore,this approach holds considerable promise for in situ polymerization,as functional conductive films can be prepared by merely combining the monomers with the DMSO/Ac_(2)O mixture and applying heat.This efficient,purification-free strategy represents a significant step toward the industrial application of the highperformance n-type conductive polymer PBFDO.展开更多
In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still face...In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.展开更多
Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this stu...Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this study,a novel p H/glutathione dual-responsive pesticide delivery system was constructed through the synthesis of disulfide-bridged hollow mesoporous organosilica nanospheres(HMONs)via the St??ber method,followed by poly(acrylic acid)(PAA)coating through distillation-precipitation polymerization to form HMONs@PAA nanocomposites.The resulting abamectin-loaded system(Abamectin-HMONs@PAA)demonstrated a 12.73% pesticide loading capacity and significantly improved photostability,retaining twice as much active ingredient as free abamectin after 250 h of UV irradiation(36 W).Release studies revealed p H-and glutathione-dependent characteristics,with cumulative releases in acidic conditions exceeding those in neutral and alkaline environments by 18.66% and 40.98%,respectively,and a 14.2% increase in glutathione-containing solution(0.2 mmol·L^(-1) in 70% ethanol)after 97 h.Bioassays showed superior performance against Plutella xylostella,with a 13.33% reduction in survival rate compared to conventional suspension at equivalent dosage(40 mg·L^(-1)),while maintaining efficacy after extensive rainfall simulation(20 events over 10 days).This study provides a promising approach for developing environmentally responsive nanopesticides with enhanced durability and controlled-release properties,offering significant potential for sustainable crop protection.展开更多
Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its...Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.展开更多
Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-...Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-end fields.To address this challenge,this study employs a supramolecular chemistry approach by simultaneously incorporating multiple hydrogen bonds as dynamic cross-linking points and a phosphorus-nitrogen synergistic flame-retardant structure into the poly(urethane-urea)network.The multiple hydrogen bonds endow the material with efficient intrinsic self-healing capability,while the phosphorus-nitrogen flame retardant ensures outstanding thermal stability and flame resistance,leading to the successful synthesis of a high-performance multifunctional poly(urethane-urea)elastomer.Experimental results demonstrated that when the content of the flame retardant diethyl(2-((2-aminoethyl)amino)ethyl)phosphoramidate(DEPTA)was 10 wt%,the resulting PUE/10%DEPTA achieved a V-0 rating in the vertical burning test,with a limiting oxygen index(LOI)of 30%.Concurrently,the elastomer maintained good toughness,exhibiting a tensile strength of 27.3 MPa,an elongation at break of 601%,and a self-healing efficiency of up to 94.46%.This breakthrough shows significant promise for advanced engineering applications that demand fire safety,structural durability,and extended service life through self-repair.展开更多
Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardan...Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardant strategies often compromise their mechanical properties,hindering their practical applications.Herein,a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)-based comonomer(DDP)was used to synthesize flame-retardant poly(ethylene furandicarboxylate-co-phosphaphenanthrene)(PEFDn).The covalent integration of DDP confers intrinsic flame retardancy,avoiding the plasticization and migration issues associated with additive-type systems.Upon thermal decomposition,the DOPO-derived moieties release phosphoric acid and radical scavengers,promoting char formation and suppressing flame propagation.Furthermore,density functional theory(DFT)calculations combined with non-covalent interaction(NCI)analysis revealed that DOPO dimer molecules adopt a stable parallel-displaced π-π stacking configu ration,potentially facilitating microphase separation and enhancing the energy dissipation capability.PEFD_(10)achieves a UL-94 V-0 rating while simultaneously increasing impact toughness from 1.5 kJ/m^(2) to 14.7 kJ/m^(2).Im portantly,PEFDn maintained acceptable oxygen-barrier properties.PEFD10 also exhibited high transparency and UV-shielding performance.The combination of intrinsic flame safety,im pact-toughness resistance,UV shielding,and an oxygen barrier ensures reliable protection of electrical components and long-term operational stability.The integration of multiple critical properties within a single bio-based material represents a novel approach fo r enabling sustainable polymer solutions for high-pe rformance electrical applications.展开更多
This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. Th...This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.展开更多
Poly(ester amide)s(PEAs)represent promising biomaterials because of their well-balanced mechanical properties,biodegradability,and biocompatibility.However,practical applications of PEAs are still limited by challenge...Poly(ester amide)s(PEAs)represent promising biomaterials because of their well-balanced mechanical properties,biodegradability,and biocompatibility.However,practical applications of PEAs are still limited by challenges in functional versatility and environmental adaptability.Here,we present the first synthesis of periodic selenium-incorporated PEAs(Se-PEAs)via a rapid,catalyst-free selenol-yne click polymerization process.By harnessing the versatility of selenium,we achieved precise modulation of material properties.The resulting Se-PEAs demonstrated tunable mechanical behavior,spanning rigid plastics to elastomers,alongside exceptional thermal stability and high optical clarity.Programmable degradation profiles ensure long-term stability in physiological environments while facilitating rapid oxidative degradation at the end of the lifecycle.Surface selenoniumization further conferred robust antibacterial efficacy without compromising mechanical integrity.This multifunctionality positions Se-PEAs as transformative materials for biomedical implants,sustainable packaging,and high-refractiveindex optics.Our work advanced functional polymer design and underscored the potential of selenium chemistry in addressing global challenges in terms of plastic waste and ecological sustainability.展开更多
The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt...The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.展开更多
A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing filler.In this work,basalt fiber assembled with in-situ SiO_(2) nanoparticles on the surface was successfull...A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing filler.In this work,basalt fiber assembled with in-situ SiO_(2) nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between polylactic acid(PLA)and basalt fibers(BF).It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC results.The tensile strength of PLA/BF composites raised from 39 MPa to 62.5 MPa with increasing the fiber loading from 1 wt%to 10 wt%.Furthermore,the interfacial interaction could be effectively improved by assembling SiO_(2)(especially with 250 nm in diameter)on BF surface to build mechanical locking,which could keep the PLA matrix in place during the mechanical deformation with the tensile strength value raised from 62.5 MPa to 74.0 MPa.It is noticeable that the impact and flexural properties were effectively increased with the incorporation of in-situ SiO_(2) nanoparticles.The further KH-550 treatment made a positive impact as well.For instance,the impact strength and flexural strength of the sample with SiO_(2) and KH-550 modification were improved to 22.49 k J/m^(2) and 146.83 MPa and it enhanced about 42.16%and 41.04%than those of neat PLA,respectively.Therefore,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO_(2) on silica-based fiber as a modifier was a novel and simple path to design the interfacial construction and properties of the polymer composites.展开更多
Scrap leather fibers(SLFs) modified with active silane containing epoxide groups were incorporated into poly(lactic acid)(PLA) modified by vinyl trimethoxysilane,i.e.,the PLA/SLF composites were prepared for bio-compo...Scrap leather fibers(SLFs) modified with active silane containing epoxide groups were incorporated into poly(lactic acid)(PLA) modified by vinyl trimethoxysilane,i.e.,the PLA/SLF composites were prepared for bio-composites by solvent compounding technology in this article.The effects of silane coupling agents on the structures of PLA and SLF molecules were examined,and the mechanical properties and thermal stability of PLA/SLF composites were also measured.The results of Fourier-transform infrared spectroscopy(FTIR) had proved that silane had been incorporated successfully to PLA and SLF molecules by means of the solvent technology.Scanning electric microscopy(SEM) was used to investigate both the changes in shapes between the pristine SLFs and the treated SLFs and the microscopic structures of composites.According to SEM results,it was shown that there were some significant differences between the untreated and treated SLFs,and a double continuous phase structure had occurred in PLA/SLF composites due to the excellent dispersion of SLFs in matrix.The addition of the treated SLFs into PLA resulted in a distinct improvement of the impact and tensile strengths.When the mass fraction of the treated SLFs was 15%,the notched impact strength and tensile strength of PLA/SLF bio-composites were improved by 34.4%and 21.2%compared with the pristine PLA,respectively. Additionally,with the increase of the modified SLFs content,the thermal stability of PLA/SLF bi-composites was apparently improved.The macroscopic properties of bio-composites were found to be strongly dependent on their components,concentration,dispersion and resulted morphological structures.展开更多
基金supported by the National Natural Science Foundation of China(Nos.31971741 and 31760195)the Yunnan Fundamental Research Projects(Nos.2018FB066 and 202001AT070141)the Yunnan Agricultural Basic Research Special Projects(No.202101BD070001-086).
文摘The increasing deployment of electronics in everyday life has generated great concerns regarding the effective disposal of waste from these components.Here,we focused on a facile sustainable and economical strategy to provide ideas for this issue.This strategy relied on using appropriate mechanical treatment and sodium lignosulfonate coating to improve the dispersion and interfacial compatibility of bamboo fibers in poly(lactic acid).By optimising the particle size and concentration of sodium lignosulphonate,high value-added and green composites were prepared using sectional pressurization with a venting procedure.The treated composite displayed an ultra-smooth surface(roughness of 0.592 nm),impressive transient properties(disintegration and degradation behaviour after 30 d),and outstanding ultraviolet(UV)shielding properties(100%).These properties hold the promise of being an excellent substrate for electronic devices,especially for high-precision processing,transient electronics,and UV damage prevention.The satisfactory interfacial compatibility of the composites was confirmed by detailed characterisation regarding the related physicochemical properties.This investigation offers a sustainable approach for producing high value-added green composites from biomass and biomass-derived materials.
基金Funded by the National Natural Science Foundation of China(No.21104031)the Education Department of Hunan province in 2020(No.20C1589)。
文摘This article provided a preparation protocol for poly(lactic acid)(PLA)/modified epoxidized soybean oil(ECP)/nano-magnesium oxide(n-MgO)ternary composites and studied their mechanical and antibacterial properties.By means of an organic synthesis technique,epoxidized soybean oil(ESO)is chemically grafted to PLA to synthesize ESO chemically plastically modified PLA,abbreviated ECP.To fabricate PLA/ECP/n-MgO composite materials,ECP acts as a plasticizer and a compatibilizer simultaneously,and n-MgO acts as an enhancer.Then scanning electron microscopy,X-ray diffraction,differential scanning calorimetry,universal tester,and antibacterial research were exploited to characterize the morphology,thermal resistance,mechanical properties,and antibacterial performance of PLA/ECP/n-MgO composites.The experimental results show that ECP acts as a plasticizer by causing heterogeneous nucleation,which increases PLA's crystallinity.Evenly distributed n-MgO can greatly improve PLA's antibacterial qualities.Furthermore,ECP and n-MgO work together to improve the positive aspects of PLA/ECP/n-MgO composites,with PLA/ECP/n-MgO 100/1/0.5 composites having the best overall properties.While improving the mechanical performance and toughness of PLA,this work offers a prospective approach and foundational database for the creation of multifunctional biodegradable composites.
基金supported by the National Key Research and Development Program of China(No.2023YFC3904604)the Fundamental Research Funds for the Central Universities(No.2024ZYGXZR080)+1 种基金Science and Technology Project of Guangzhou(No.2025A04J3914)Research and Development Program of Jiangmen(No.2023780200030009506).
文摘To retain its inherent biodegradability,simultaneously improving the strength and toughness of poly(lactic acid)(PLA)is a significant challenge.In this study,we propose an innovative multiple dynamic pressure(MDP)process that can produce pure PLA with excellent mechanical properties.The MDP process generates a dynamic stretching effect by regulating the application and release of pressure,prompting disordered molecular chains to be arranged regularly along the direction of the dynamic force field.This promoted the formation of more ordered crystal forms(α-form)and strengthened the connection between the crystalline and amorphous regions.Results show that after MDP treatment,the tensile strength and strain at break of MDP-PLA are significantly improved,reaching 91.6 MPa and 80.1%respectively,which are 49.4%higher and 10 times higher than those of the samples before treatment.The mechanical properties of MDP-PLA can be regulated as needed by adjusting the cycle times and peak pressure.In addition,through a systematic study of the structural evolution of MDP-PLA,the performance regulation mechanism of the MDP process was thoroughly investigated,and the internal relationship among the process-structure-performance was clarified.This research not only opens a new technical path for the preparation of high-performance pure PLA but also provides important guidance for the high-performance modification of other semi-crystalline polymers,thus possessing significant scientific and engineering value.
基金This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoalde Nível Superior-Brasil(CAPES)-Finance Code 001.
文摘The continuous improvement in patient care and recovery is driving the development of innovative materials for medical applications.Medical sutures,essential for securing implants and closing deep wounds,have evolved to incorporate smart materials capable of responding to various stimuli.This study explores the potential of thermoresponsive sutures,made from shape memory materials,that contract upon heating to bring loose stitches closer together,promoting optimal wound closure.We developed nanocomposites based on a blend of poly(lactic acid)(PLA)and thermoplastic polyurethane(TPU)—biopolymers that inherently exhibit shape memory—enhanced with carbon nanotubes(CNT)and graphene nanoplatelets(GN)to improve mechanical performance.PLA/TPU(50/50)nanocomposites were prepared with 1 and 2 wt%GN,as well as hybrid formulations combining 1 wt%CNT with 1 or 2 wt%GN,using a twin-screw extrusion process to form filaments.These filaments were characterized through differential scanning calorimetry(DSC),field emission gun scanning electron microscopy(FEG-SEM),tensile testing,and shape memory assessments.While the PLA/TPU blend is immiscible,TPU enhances the crystallinity(X_(c))of the PLA phase,further increased by the addition of CNT and GN.FEG-SEM images indicate CNTs primarily in the PLA phase and GN in the TPU phase.PLA/TPU with 1 or 2 wt%GN showed the highest potential for suture applications,with a high elastic modulus(~1000 MPa),significant strain at break(~10%),and effective shape recovery(~20%at 55℃ for 30 min).These findings suggest that these nanocomposites can enhance suture performance with controlled shape recovery that is suitable for medical use.
基金financially supported by the National Key R&D Program of China(No.2021YFB3801901)the National Natural Science Foundation of China(No.22075188 and U19A2095)supported by State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology。
文摘Poly(lactic acid)(PLA),a bio-based polymer,is considered to be a sustainable alternative to conventional petroleum-based plastics.However,owing to its widespread use and relatively slow degradation rate in water,PLA still poses potential environmental pollution risks after being discarded.The efficient chemical recycling of PLA represents an attractive approach to addressing both resource reuse and environmental pollution challenges caused by its waste.Hydrolysis is the predominant method of industrial recycling.However,because PLA is insoluble in water,efficient heterogeneous hydrolysis requires high-temperature and high-pressure conditions.In this study,an efficient homogenous hydrolysis method capable of simultaneously dissolving PLA and calcium hydroxide(Ca(OH)_(2))was developed.Suitable solvents for this method were screened,and it was found that PLA hydrolysis using dioxane and 1,4,7,10,13-Pen-taoxacyclopentadecane as solvents achieved conversion rates of 93%and 90%,respectively,within 2 h at room temperature.Notably,the hydrolysis product,calcium lactate,precipitated as a solid from the solvent and therefore self-separated from the reaction solution.The solvent,acid/base conditions,water content,and depolymerization kinetics were investigated.Compared with previously reported hydrolysis methods,the enhanced efficiency observed in this study can be attributed to the concurrent solvation of PLA and Ca(OH)_(2),which maintains homogeneity throughout the reaction process.Additionally,this method facilitates closed-loop recycling of PLA and is compatible with the highly selective recovery of PLA from various types of PLA products.
基金Supported by the National Natural Science Foundation of China(No.82301211)Beijing Natural Science Foundation(No.J230028).
文摘AIM:To develop a 5-fluorouracil(5-FU)mesoporous poly(lactic)acid(PLA)delivery system for glaucoma filtration surgery suitable for a single subconjunctival implantation.METHODS:The 5-FU was infiltration-loaded into mesoporous PLA.In vitro and in vivo release experiments and ocular toxicology evaluation of the formulation were performed.The antiproliferative effect of this 5-FU-PLA tablet after glaucoma filtration surgery in rabbits was evaluated.Pathology,immunohistochemistry,and Western blot were used to further validate the inhibitory effect of this sustained release system.RESULTS:Various drug formulations were tested,and two 5-FU-PLA tablets,namely 1.5P15(5-FU 1.5 mg+PLA 15000 Da)and 2.5P15(5-FU 2.5 mg+PLA 15000 Da),had the most suitable release profiles in vitro.Further in vivo studies confirmed the safety and sustained-release profiles of both drugs.Both 5-FU-PLA tablets,relative to the free drugs,significantly inhibited tissue proliferation after glaucoma filtration and improved surgical success.Western blot showed that transforming growth factor-β(TGF-β)and connective tissue growth factor(CTGF)were inhibited by 5-FU after filtration surgery,with the effects of the 5-FU-PLA tablets being more lasting.CONCLUSION:The tested 5-FU-PLA tablets provide a sustained release of 5-FU,which may be used for a single subconjunctival implantation to inhibit proliferation after filtration surgery.
基金supported by the Natural Science Foundation of Heilongjiang Province(LH2021C075)Basic Research Business Expenses and Research Projects of Provincial Higher Education Institutions in Heilongjiang Province(2022-KYYWF-1077).
文摘Lactic acid bacteria(LAB)exopolysaccharides(EPS)reveal high safety and multiple activities,and are typical postbiotics produced by LAB during fermentation.In this paper,6583 articles on LAB-EPS from Web of Science and Elsevier databases were retrieved,and 236 articles related to this review were screened.The EPS from 90 LAB strains were summarized in terms of their extraction methods,yield,molecular weight,monosaccharide composition,glycosidic bond configuration and the structural and activity relationships(SARs).However,there exist great challenges as for the low yield and high cost in EPS production.Therefore,this review further elaborated the mechanism of EPS secretion,the anabolic pathway of EPS,the structure and mechanism of key enzymes involving in EPS synthesis process,the prospect of gene regulation for EPS secretion,and proposed the engineering strategies for increasing EPS yield or tailored EPS design in recent years.In addition,CRISPR/Cas9 gene editing technology was also discussed in the production control of EPS in LAB.Finally,the engineering strategy of increasing EPS yield in recent years was proposed.This work might provide important theoretical support for the production and application of LAB-based EPS.
文摘Herein,manganese(Mn)‑doped poly(1,5‑diaminonaphthalene)(PN)electrode material(Mn@PN)was synthesized via chemical oxidative polymerization.The material′s distinctive vesicular architecture enables rapid ion transport while maintaining the structural stability of the electrode under continuous charge‑discharge cycles.Electrochemical characterization under a three‑electrode system revealed exceptional rate capability:Mn@PN delivered an ultrahigh specific capacitance of 10318 F·g^(-1) at a low current density of 3 A·g^(-1) and retained 9415 F·g^(-1)(91.2%retention compared to the value at 3 A·g^(-1))even at an ultrahigh current density of 50 A·g^(-1).Moreover,the material exhibited 97.4%capacitance retention after 9000 cycles at 30 A·g^(-1),corresponding with a low capacitance decay rate of 0.003‰per cycle,significantly outperforming conventional conductive polymers like polyaniline(PANI).An asymmetric supercapacitor assembled with Mn@PN as the positive electrode(Mn@PN||AC)achieved an energy density of 328 Wh·kg^(-1) at 15 A·g^(-1) and retained 80.7%of its initial specific capacitance after 4000 cycles at 20 A·g^(-1).
文摘BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis and heart failure has rarely been observed in cases of pediatric patients with CH pathology.Here,we explored the etiological relationship between CH,heart failure,and refractory lactic acidosis to reflect the importance of thyroid function screening in neonates with heart disease.CASE SUMMARY A 33-day-old extremely premature female infant presented with tachypnea,respiratory distress,recurrent infections,and abdominal distension postnatal.On admission to our facility,she had cardiomegaly,hepatomegaly,and lactic acidosis(revealed on blood gas analysis),with lactate progressively rising to 25 mmol/L.Chest radiographs showed pulmonary congestion,while echocardiography revealed cardiac enlargement,left ventricular wall thickening,and pericardial effusion.Initial management aimed at correcting acidosis and treating heart failure proved ineffective.After reassessment,thyroid function tests showed significantly decreased triiodothyronine,free triiodothyronine,thyroxine,and free thyroxine levels,with a significantly increased thyroidstimulating hormone level,confirming a CH diagnosis.Levothyroxine was administered,resulting in rapid correction of lactic acidosis and gradual improvement of thyroid function and systemic symptoms,culminating in full recovery and discharge.We also reviewed the relevant literature on thyroid and cardiac dysfunctions in order to explore their deeper association.CONCLUSION This case links CH-induced heart failure with refractory lactic acidosis,urging prompt thyroid screening in affected neonates to reduce mortality.
基金supported by the National Natural Science Foundation of China(52433012)the National Key R&D Program of China(2024YFF1500300)the China Postdoctoral Science Foundation(2023M741201,2024T170286)。
文摘Conductive polymers have recently drawn tremendous attention due to their promising applications in electronic and energy-related devices.While p-type conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)have achieved commercialization,the development of stable,high-performance n-type polymers has lagged.Recently,the discovery of n-type polymer poly(benzodifurandione)(PBFDO)has greatly promoted the development and application of n-type conductive polymers.However,the synthesis process involves cumbersome post-processing,which greatly increases the cost and difficulty of mass production.Herein,a novel synthesis method for PBFDO has been developed,which was promoted by the combination of solvent dimethyl sulfoxide(DMSO)and acetic anhydride(Ac_(2)O).This method exploits the oxidative capability of DMSO,activated by Ac_(2)O,which can promote the keto-enol tautomerism of 3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione(BFDO)and induce the rapid polymerization.The resulting PBFDO ink exhibits a high electronic conductivity of more than 2000 S cm^(-1)and excellent ambient stability.Significantly,the additives and by-products remain in a liquid state during the polymerization process and possess low boiling points,allowing for the production of pure PBFDO films through straightforward heating and drying.Furthermore,this approach holds considerable promise for in situ polymerization,as functional conductive films can be prepared by merely combining the monomers with the DMSO/Ac_(2)O mixture and applying heat.This efficient,purification-free strategy represents a significant step toward the industrial application of the highperformance n-type conductive polymer PBFDO.
基金the financial support from the National Natural Science Foundation of China (No. 52072390)the National High-Level Talents Special Support Program (Leading Talent of Technological Innovation)+2 种基金the China Postdoctoral Science Foundation (No. 2023M743648)the Young Scientists Fund of the National Natural Science Foundation of China (No. 52302330)the support from the Shanghai Emperor of Cleaning Hi-Tech Co.,LTD
文摘In-situ poly(1,3-dioxolane)(PDOL)-based electrolyte has received extensive attention in the research of lithium metal batteries due to its high stability to lithium anode and simple processing.However,it is still faced with defects such as low intrinsic ionic conductivity,a narrow electrochemical window,and poor thermal stability.A crosslinking and fluorination molecular design strategy toward PDOL is proposed to tackle the issues above.The amorphous crosslinked structure effectively improves ionic conductivity by inhibiting long-chain crystallization.Especially,the antioxidant–CF_(3)groups,stable crosslinked structure,and reduced terminal hydroxyl groups significantly enhance the electrochemical oxidation stability with a superb high-voltage window of 4.7 V.In addition,the designed electrolyte also exhibits obviously improved thermal stability with no deformation at 120°C for 5 min.Furthermore,the semi-solid NCM811||Li batteries exhibit a favourable capacity retention of 88.8%after 150 cycles at 0.5 C.Even assembled with NCM622 cathode working at 4.5 V,the semi-solid batteries can still show a satisfactory capacity retention of 85.3%after 100 cycles at 0.5 C.Also,a 0.1 Ah NCM811||Li pouch cell with active materials loading of 9 mg/cm2 demonstrates satisfactory cycling stability and working ability,which shows promising practical application prospects.
基金financially supported by the Jiangsu Forestry Science and Technology Innovation and Promotion Project(No.LYKJ-Nanjing[2022]02)the Jiangsu Agricultural Science and Technology Innovation Fund(No.CX(23)3090)。
文摘Smart pesticide delivery systems based on stimuli-responsive nanocarriers have attracted considerable attention because of their potential to enhance pesticide efficiency while reducing environmental risks.In this study,a novel p H/glutathione dual-responsive pesticide delivery system was constructed through the synthesis of disulfide-bridged hollow mesoporous organosilica nanospheres(HMONs)via the St??ber method,followed by poly(acrylic acid)(PAA)coating through distillation-precipitation polymerization to form HMONs@PAA nanocomposites.The resulting abamectin-loaded system(Abamectin-HMONs@PAA)demonstrated a 12.73% pesticide loading capacity and significantly improved photostability,retaining twice as much active ingredient as free abamectin after 250 h of UV irradiation(36 W).Release studies revealed p H-and glutathione-dependent characteristics,with cumulative releases in acidic conditions exceeding those in neutral and alkaline environments by 18.66% and 40.98%,respectively,and a 14.2% increase in glutathione-containing solution(0.2 mmol·L^(-1) in 70% ethanol)after 97 h.Bioassays showed superior performance against Plutella xylostella,with a 13.33% reduction in survival rate compared to conventional suspension at equivalent dosage(40 mg·L^(-1)),while maintaining efficacy after extensive rainfall simulation(20 events over 10 days).This study provides a promising approach for developing environmentally responsive nanopesticides with enhanced durability and controlled-release properties,offering significant potential for sustainable crop protection.
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C01072)the Institute of Zhejiang University-Quzhou for their financial support。
文摘Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.
文摘Although poly(urethane-urea)elastomers(PUEs)possess excellent mechanical properties and durability,their inherent flammability and inability to self-repair after damage significantly limits their applications in high-end fields.To address this challenge,this study employs a supramolecular chemistry approach by simultaneously incorporating multiple hydrogen bonds as dynamic cross-linking points and a phosphorus-nitrogen synergistic flame-retardant structure into the poly(urethane-urea)network.The multiple hydrogen bonds endow the material with efficient intrinsic self-healing capability,while the phosphorus-nitrogen flame retardant ensures outstanding thermal stability and flame resistance,leading to the successful synthesis of a high-performance multifunctional poly(urethane-urea)elastomer.Experimental results demonstrated that when the content of the flame retardant diethyl(2-((2-aminoethyl)amino)ethyl)phosphoramidate(DEPTA)was 10 wt%,the resulting PUE/10%DEPTA achieved a V-0 rating in the vertical burning test,with a limiting oxygen index(LOI)of 30%.Concurrently,the elastomer maintained good toughness,exhibiting a tensile strength of 27.3 MPa,an elongation at break of 601%,and a self-healing efficiency of up to 94.46%.This breakthrough shows significant promise for advanced engineering applications that demand fire safety,structural durability,and extended service life through self-repair.
基金financially supported by the National Key Research and Development Program of China(No.2021YFB3700300)the National Natural Science Foundation of China(Nos.52573017 and U21B2093)+1 种基金Key Research and Development Program of Ningbo(No.2022Z200)the Zhejiang Provincial Natural Science Foundation(No.LY23E030005)。
文摘Bio-based 2,5-furandicarboxylic acid polyesters offer significant promise for reducing energy and environmental crises.However,their intrinsic flammability remains a critical limitation,and conventional flame-retardant strategies often compromise their mechanical properties,hindering their practical applications.Herein,a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)-based comonomer(DDP)was used to synthesize flame-retardant poly(ethylene furandicarboxylate-co-phosphaphenanthrene)(PEFDn).The covalent integration of DDP confers intrinsic flame retardancy,avoiding the plasticization and migration issues associated with additive-type systems.Upon thermal decomposition,the DOPO-derived moieties release phosphoric acid and radical scavengers,promoting char formation and suppressing flame propagation.Furthermore,density functional theory(DFT)calculations combined with non-covalent interaction(NCI)analysis revealed that DOPO dimer molecules adopt a stable parallel-displaced π-π stacking configu ration,potentially facilitating microphase separation and enhancing the energy dissipation capability.PEFD_(10)achieves a UL-94 V-0 rating while simultaneously increasing impact toughness from 1.5 kJ/m^(2) to 14.7 kJ/m^(2).Im portantly,PEFDn maintained acceptable oxygen-barrier properties.PEFD10 also exhibited high transparency and UV-shielding performance.The combination of intrinsic flame safety,im pact-toughness resistance,UV shielding,and an oxygen barrier ensures reliable protection of electrical components and long-term operational stability.The integration of multiple critical properties within a single bio-based material represents a novel approach fo r enabling sustainable polymer solutions for high-pe rformance electrical applications.
基金financially supported by the National Natural Science Foundation of China(Nos.22473105 and 22341302).
文摘This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.
基金supported by the National Natural Science Foundation of China(21971177)the Natural Science Foundation of the Jiangsu Higher Education Institution of China(22KJA150004)+3 种基金the Suzhou Science and Technology Bureau(SZM2021008)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutionsthe Jiangsu Key Laboratory of Advanced Functional Polymers Design and Application,Soochow University,Suzhou Medical and Industrial Cooperation Innovation Project(SZM2022011)the Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis and the Program of Innovative Research Team of Soochow University。
文摘Poly(ester amide)s(PEAs)represent promising biomaterials because of their well-balanced mechanical properties,biodegradability,and biocompatibility.However,practical applications of PEAs are still limited by challenges in functional versatility and environmental adaptability.Here,we present the first synthesis of periodic selenium-incorporated PEAs(Se-PEAs)via a rapid,catalyst-free selenol-yne click polymerization process.By harnessing the versatility of selenium,we achieved precise modulation of material properties.The resulting Se-PEAs demonstrated tunable mechanical behavior,spanning rigid plastics to elastomers,alongside exceptional thermal stability and high optical clarity.Programmable degradation profiles ensure long-term stability in physiological environments while facilitating rapid oxidative degradation at the end of the lifecycle.Surface selenoniumization further conferred robust antibacterial efficacy without compromising mechanical integrity.This multifunctionality positions Se-PEAs as transformative materials for biomedical implants,sustainable packaging,and high-refractiveindex optics.Our work advanced functional polymer design and underscored the potential of selenium chemistry in addressing global challenges in terms of plastic waste and ecological sustainability.
基金support from the National Natural Science Foundation of China(Grant Nos.21908031 and 51903092)the China Postdoctoral Science Foundation funded project(Grant No.2019M652884)support from Guangdong Special Support Program(Grant No.2017TX04N371)。
文摘The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.
基金funded by China Postdoctoral Science Foundation(No.2018M643699)the Xi’an Science and Technology Bureau Innovation Leading Projects(No.201805037YD15CG21(23))+2 种基金the Natural Science Foundation of Shaanxi Province(No.2019JQ741)the Science and Technology Bureau of Beilin District,Xi’an(No.GX2035)the Postdoctoral Science Foundation of Shaanxi Province(No.2018BSHEDZZ101)。
文摘A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing filler.In this work,basalt fiber assembled with in-situ SiO_(2) nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between polylactic acid(PLA)and basalt fibers(BF).It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC results.The tensile strength of PLA/BF composites raised from 39 MPa to 62.5 MPa with increasing the fiber loading from 1 wt%to 10 wt%.Furthermore,the interfacial interaction could be effectively improved by assembling SiO_(2)(especially with 250 nm in diameter)on BF surface to build mechanical locking,which could keep the PLA matrix in place during the mechanical deformation with the tensile strength value raised from 62.5 MPa to 74.0 MPa.It is noticeable that the impact and flexural properties were effectively increased with the incorporation of in-situ SiO_(2) nanoparticles.The further KH-550 treatment made a positive impact as well.For instance,the impact strength and flexural strength of the sample with SiO_(2) and KH-550 modification were improved to 22.49 k J/m^(2) and 146.83 MPa and it enhanced about 42.16%and 41.04%than those of neat PLA,respectively.Therefore,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO_(2) on silica-based fiber as a modifier was a novel and simple path to design the interfacial construction and properties of the polymer composites.
基金the China Postdoctoral Science Foundation (No.20100470755)the Financial Supports of Department of Education of Zhejiang Province (No.Z20119661)
文摘Scrap leather fibers(SLFs) modified with active silane containing epoxide groups were incorporated into poly(lactic acid)(PLA) modified by vinyl trimethoxysilane,i.e.,the PLA/SLF composites were prepared for bio-composites by solvent compounding technology in this article.The effects of silane coupling agents on the structures of PLA and SLF molecules were examined,and the mechanical properties and thermal stability of PLA/SLF composites were also measured.The results of Fourier-transform infrared spectroscopy(FTIR) had proved that silane had been incorporated successfully to PLA and SLF molecules by means of the solvent technology.Scanning electric microscopy(SEM) was used to investigate both the changes in shapes between the pristine SLFs and the treated SLFs and the microscopic structures of composites.According to SEM results,it was shown that there were some significant differences between the untreated and treated SLFs,and a double continuous phase structure had occurred in PLA/SLF composites due to the excellent dispersion of SLFs in matrix.The addition of the treated SLFs into PLA resulted in a distinct improvement of the impact and tensile strengths.When the mass fraction of the treated SLFs was 15%,the notched impact strength and tensile strength of PLA/SLF bio-composites were improved by 34.4%and 21.2%compared with the pristine PLA,respectively. Additionally,with the increase of the modified SLFs content,the thermal stability of PLA/SLF bi-composites was apparently improved.The macroscopic properties of bio-composites were found to be strongly dependent on their components,concentration,dispersion and resulted morphological structures.
