The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil res...The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil resources.However,the chemical recycling of polyesters primarily involves polymer-to-monomer and monomer-to-polymer processes,resulting in significant greenhouse gas emissions owing to significant electricity and fuel consumption.Herein,this research reports a simple and efficient one-pot polymer-to-polymer upcycling process that directly converts these two polyester wastes into biodegradable thermoplastic poly(ether ester)s using poly(tetramethylene ether)glycol(PTMG).The synthesized series of poly((ET-co-BT)-mb-PTMG)(PEBTG)exhibit a maximum tensile strength of 68 MPa,with 85%weight loss after 20 weeks in composted soil.Techno-economic analysis and life cycle assessment indicate that PEBTG is more cost-competitive and environmentally beneficial than currently existing plastics derived from fossil fuels,such as polypropylene and polybutylene adipate terephthalate.Once de-risked,the proposed upcycling strategy for polymer waste can be extended to expedite the development of a sustainable plastic economy.展开更多
This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experi...This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.展开更多
Two kinds of tough ductile heatresisting thermoplastic, namely bisphenol A polysulfone (PSF) and polyethersulfone (PES) were used to toughen thermoset epoxy resin. A systematic study on the relationship between the mo...Two kinds of tough ductile heatresisting thermoplastic, namely bisphenol A polysulfone (PSF) and polyethersulfone (PES) were used to toughen thermoset epoxy resin. A systematic study on the relationship between the molecular weight and the terminal group of the thermoplastic modifier and the fracture toughness of the modified resin was carried out. The morphology of PSF modified epoxy resin was surveyed. With the same kind of PSF the structure of the epoxy resin and the toughening effect of PSF was also investigated. The fractography of PSF, particle modified epoxy was examined in detail with SEM. The contribution of every possible energy absorption process has been discussed. Crack pinning mechanism seems to be the most important toughening mechanism for tough ductile thermoplastic PSF particle modified epoxy system.展开更多
Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer ...Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer or using theμTM method. By repeated molding, crossed structures were produced with a stamp prepared only with lines. The processingvariables including the softening temperature of the polymers and heating time were discussed. The result shows that theoptimal molding temperature is preferably slightly higher than the melting temperature of the thermoplastic polymers, atwhich polymers are in the critical states of being melted. This method can be applied to many polymers except those with high softening temperatures or high rate of shrinkage upon temperature change.展开更多
The stabilization of vibration amplitude is an important factor for assuring welding quality. In this paper, the electric parameter for monitoring the output vibration amplitude of the transducer is determined by the ...The stabilization of vibration amplitude is an important factor for assuring welding quality. In this paper, the electric parameter for monitoring the output vibration amplitude of the transducer is determined by the analysis of electromechanical analogy,and matching circuits of constant current for the ultrasonic transducer are analyzed and compared. Series matching circuit is designed and analyzed using the method of impedance transformation. The output vibration amplitude of the transducer can be kept constant when the value of electric parameter for the matching circuit is chosen reasonably. The results of analysis is verified by technological experiments.展开更多
Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticiz...Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.展开更多
The recovery of thermoplastics has a major impact on our cities,both in terms of the environmental impact of waste disposal and the economic impact of its use in construction materials.The aim of this study is to manu...The recovery of thermoplastics has a major impact on our cities,both in terms of the environmental impact of waste disposal and the economic impact of its use in construction materials.The aim of this study is to manufacture bricks from recycled thermoplastics,more specifically low-density polyethylene(LDPE)packaging from households and landfill sites in the 9th arrondisse-ment.The technological evolution that humanity has undergone in recent years has made a wide variety of building materials available,and the use of earth as a material will make use of certain secondary products known as ad-ditives.These additions may be of mineral,animal or vegetable origin,and also of low purchasing power,but create a very strong bond once they are combined.The main aim of the present work is to contribute to the character-ization of bricks produced from thermoplastics and a soil sample taken from the bank of the Chari at Toukra in the 9th arrondissement of the capital,which are resistant to natural hazards such as bad weather and flooding,which al-ways cause enormous losses with each passing season.The results of the vari-ous tests carried out show that the material can help to overcome not only the lack of mechanical strength,but also the impermeability that is the cause of the deterioration and ruin of the building in clay without any addition modi-fying its properties.展开更多
Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although signific...Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although significant attention has recently been given to recycling various waste materials into concrete,studies specifically addressing thermoplastic recycled aggregates are still trending.This underscores the need to comprehensively review existing literature,identify research trends,and recognize gaps in understanding the mechanical performance of thermoplastic-based recycled aggregate concrete.Accordingly,this review summarizes recent investigations focused on the mechanical properties of thermoplastic-based recycled aggregate concrete,emphasizing aspects such as compressive strength,tensile behavior,modulus of elasticity,and durability characteristics.The primary aim is to consolidate scattered research findings,identify key parameters influencing mechanical behavior,and propose future research directions.Understanding the influence of recycled thermoplastic aggregates on concrete performance significantly supports sustainable construction practices by reducing dependency on virgin aggregates and mitigating environmental impacts associated with waste disposal.In addition,assessing mechanical performance contributes to confidence in the practical application,encouraging the broader adoption of thermoplastic-based recycled aggregate concrete in construction projects.Through this critical synthesis,the review guides researchers and industry practitioners toward informed decisions on the feasibility and reliability of integrating thermoplastic waste into concrete,thereby promoting sustainable infrastructure development.展开更多
Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promo...Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promoting dissociation of ions from the lithium salt.Thus,TPU attracts a wide interest recently as a promising polymer electrolyte for solid-state lithium batteries.However,the relatively low ionic conductivity of TPU still restricts its actual applications due to the aggregation of polymer chains,which greatly reduces the dissociation of lithium salts.Herein,a strategy to address this challenge was adopted by in situ polymerization poly(ethylene glycol diacrylate)(PEGDA)in fully dispersed TPU.Hence a stretchable solid-state electrolyte(denoted as TELL and the contrast sample was denoted as TLL)with high ionic conductivity of 7.18×10^(-4) S/cm was obtained at room temperature.The Li^(+)transference number is 0.85 in Li|TELL|Li cell and can stably undergo charge-discharge cycles for 1400 h at a current density of O.1 mA/cm^(2),while the contrast sample is short-circuited after 634 h of cycling.The LiFePO_(4)|TELL|Li cell achieves a capacity retention of 78.93%after 200 cycles at 2 C.The LiFePO_(4) TLL Li cellonly gains the capacity retention of 51.9%after 50 cyclesat the same current density.So,the method adopted here may provide a new approach to realize a flexible solid-state electrolyte with high ion-conductivity.展开更多
The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature(UCST)or lower critical solution temperature(LCST)were studied wit...The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature(UCST)or lower critical solution temperature(LCST)were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window.We found that the phase separation time/temperature relationship follows the simple Arrhenius equation.The cure-induced phase separation activation energy E_(a)(ps)generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time.We also found that E_(a)(ps)is insensitive to TP content,TP molecular weight and curing rate,but it changes with the cure reaction kinetics and the chemical environment of the systems.With the established phase separation time-temperature dependence relation,we can easily establish the whole cure time-temperature transformation(TTT)diagram with morphology information which is a useful map for the TP/TS composites processing industry.展开更多
This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Depos...This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Deposition Modeling(FDM)technology,highlighting the immense potential of this innovative approach.The use of FDM additive manufacturing technology to print gun propellants is a significant advancement due to its novel application in this field,which has not been previously reported.Through this study,the potential of FDM 3D-printing in the production of high-performance energetic composites is demonstrated,and also a new standard for manufacturability in this field can be established.The thermoplastic composites developed in this study are characterized by a notably high energetic solids content,comprising 70%hexogen(RDX)and 10%nitrocellulose(NC),which surpasses the conventional limit of 60%energetic solids typically achieved in stereolithography and light-curing 3D printing methods.The primary objective of the study was to optimize the formulation,enhance performance,and establish an equilibrium between printability and propellant efficacy.Among the three energetic for-mulations developed for 3D printing feedstock,only two were suitable for printing via the FDM tech-nique.Notably,the formulation consisting of 70%RDX,10%NC,and 20%polycaprolactone(PCL)emerged as the most advantageous option for gun propellants,owing to its exceptional processability,ease of printability,and high energetic performance.展开更多
Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic ...Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic thermoplastic polyurethane/carbon nanotubes/graphene nanosheets flexible strain sensor (TCGS) hasbeen developed using a combination of micro-extrusion compression molding andsurface modification for real-time wireless detection of liquid leakage. The TCGSutilizes the synergistic effects of Archimedean spiral crack arrays and micropores,which are inspired by the remarkable sensory capabilities of scorpions. This designachieves a sensitivity of 218.13 at a strain of 2%, which is an increase of 4300%. Additionally, it demonstrates exceptional durability bywithstanding over 5000 usage cycles. The robust superhydrophobicity of the TCGS significantly enhances sensitivity and stability indetecting small-scale liquid leakage, enabling precise monitoring of liquid leakage across a wide range of sizes, velocities, and compositionswhile issuing prompt alerts. This provides critical early warnings for both industrial pipelines and potential liquid leakage scenariosin everyday life. The development and utilization of bioinspired ultrasensitive flexible strain sensors offer an innovative and effectivesolution for the early wireless detection of liquid leakage.展开更多
Bio-based thermoplastic film from flax fiber and fatty acid(FA)was obtained using trifluoroacetic anhydride(TFAA)as an impelling agent.Different quantities of TFAA/FA,size of flax fiber,and fatty acids were applied to...Bio-based thermoplastic film from flax fiber and fatty acid(FA)was obtained using trifluoroacetic anhydride(TFAA)as an impelling agent.Different quantities of TFAA/FA,size of flax fiber,and fatty acids were applied to investigate chemical structure in relation to the mechanical properties.Decreasing the quantity of TFAA/FA by almost half from 1:4 to 1:2.5(flax to TFAA/FA)only reduces by 22%the weight percent gain(WPG)and ester content and reducing flax fiber size slightly increases the WPG and ester content.All the treatments showed sig-nificant chemical structure modification,observed by FTIR and solid CP/MAS^(13)C NMR,confirming the presence of carbonyl ester groups and alkyl chains,in relatively similar intensities.The crystallinity index(CrI)of esterified flax was evaluated by comparing the signal of solid CP/MAS^(13)C NMR in crystalline and amorphous regions and CrI was higher in esterified flax using a lower quantity of reagent and longer fatty acid.Esterified flax in a high quantity of reagent showed ductile or flexible behavior.Decreasing the reagent to 1:2.5 significantly increases the tensile strength and Young’s modulus,and decreases the elongation at break,presenting more brittle and stiff material.Using flax fiber in the original size results in slightly higher tensile strength and Young’s modulus and slightly lower elongation than milled flax.The tensile strength and Young’s modulus of stearic acid esterified flax obtained in this research were higher than myristic acid and comparable to the polyethylene plastics-LDPE and HDPE.展开更多
The use of wood-polymer composites(WPC)based on a polymer matrix and wood filler is a modern,environmentally friendly direction in material science.However,untreated wood filler exhibits poor adhesion to hydrophobic p...The use of wood-polymer composites(WPC)based on a polymer matrix and wood filler is a modern,environmentally friendly direction in material science.However,untreated wood filler exhibits poor adhesion to hydrophobic polymers due to its hydrophilic lignocellulose fibers.To address this,ozone treatment is employed to enhance compatibility,reduce water absorption,and regulate biodegradation rates.This study investigates the hypothesis that ozone modification of wood filler improves adhesion to thermoplastic starch,thereby enhancing the physico-mechanical properties and controlled biodegradation of WPCs under compost conditions.A compre-hensive analysis was conducted on composites containing untreated and ozonated wood flour,focusing on tensile strength,bending resistance,impact strength,and biodegradation kinetics.Results showed significant improvements in mechanical properties for modified composites:tensile strength increased by 20%-25%,bending resistance by 15%-30%,and impact strength by 15%-20% compared to untreated samples.The optimal composition identified contained 70% ozonated wood flour and 30% thermoplastic starch(70WF/30P),demonstrating excellent mechanical strength(flexural strength of 18-22MPa),complete biodegradation within 140 days,and operational stability.The study revealed correlations between surface modification,interphase interaction,and biodegradation kinetics,advancing fundamental knowledge of lignocellulosic filler modification methods.These findings are crucial for developing eco-friendly composite materials with applications in biodegradable packaging and agricultural products,offering both scientific insights and practical solutions for sustainable material development.展开更多
This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubbe...This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.展开更多
Electromagnetic pollution is becoming significantly serious.Therefore,it is critical to prepare the advanced electromagnetic interference(EMI)shielding materials with thinness,flexibility and high mechanical strength....Electromagnetic pollution is becoming significantly serious.Therefore,it is critical to prepare the advanced electromagnetic interference(EMI)shielding materials with thinness,flexibility and high mechanical strength.Herein,the copperbased metal-organic framework(MOF-Cu)and polyethyleneiminemodified ammonium polyphosphate(PEI-APP)were successfully synthesized.The flame-retardant thermoplastic polyurethane(TPU)composite was successfully prepared by compounding MOF-Cu and PEI-APP.The Cotton@PDA@MXene composite was fabricated via a sequential loading process of polydopamine(PDA)and MXene onto cotton fabric.Then,the multilayer TPU composites were prepared by layer-by-layer hot-pressing.The TPU/9PAPP/1MOF/C-3PM composite exhibited exceptional EMI effectiveness of 20.5 dB in X-band and 23.0 dB in K-band,exceeding commercial standards.The TPU/9P-APP/1MOF/C-3PM composite also demonstrated significantly enhanced flame retardancy.Compared with pure TPU/Cotton sample,the peak heat release rate,total heat release and total smoke release of TPU/9PAPP/1MOF/C-3PM composite decreased by 40.7%,31.1%,and 33.3%,respectively.Furthermore,the thickness of the multilayer TPU composites was only 1 mm,demonstrating excellent flexibility.As the outer encapsulation material,TPU endowed the multilayer TPU composites outstanding durability and effectively addressed the common issues of fabric abrasion and conductive filler detachment.This study provides a novel strategy for preparing flexible electromagnetic interference shielding materials with superior flame retardancy.展开更多
Adjusting the structure of the hard segment(HS)represents a key method for manipulating the mechanical properties of thermoplastic polyurethane(TPU).This study developed a novel molecular design strategy to tailor TPU...Adjusting the structure of the hard segment(HS)represents a key method for manipulating the mechanical properties of thermoplastic polyurethane(TPU).This study developed a novel molecular design strategy to tailor TPU's mechanical performance through altering the terminal diisocyanate structure of HS.The typical HDI-BDO based TPU was chosen as a model.Replacing HS's terminal HDI residues with aromatic PPDI,TODI,and MDI(the corresponding TPUs are named as 2P,2TO,and 2M,respectively)enabled broad tuning of TPU's Young's modulus while maintaining high tensile strength and elongation.Compared with linear PPDI and TODI,the bent and unsymmetrical MDI exhibits greater deviation from the central axis of the middle HDI-BDO segment,which reduces HS's capability of three-dimensionally ordered packing.Therefore,2P and 2TO show higher hydrogen bond content and crystallinity,stronger physical crosslinking network,and thus much higher Young's modulus than 2M(75.6 MPa).Besides geometric structure,π–πstacking between HS's terminal aromatic diisocyanates critically governs TPU's physical crosslinking network.In 2P,π–πstacking induces torsion of the middle HDI-BDO segment and disrupts the neighboring hydrogen bonds,leading to a dense network with fine hard blocks.In contrast,the lateral methyl groups in TODI hinderπ–πstacking,resulting in a sparse network with large hard blocks.Accordingly,2TO exhibits a higher Young's modulus(146.2 MPa)than 2P(124.0 MPa),but greater strain-rate sensitivity.展开更多
The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach...The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.展开更多
基金supported by grants from the National Research Foundation of Korea(NRF),funded by the Korean government(RS-2024-00408795 and RS-2024-00466473).
文摘The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil resources.However,the chemical recycling of polyesters primarily involves polymer-to-monomer and monomer-to-polymer processes,resulting in significant greenhouse gas emissions owing to significant electricity and fuel consumption.Herein,this research reports a simple and efficient one-pot polymer-to-polymer upcycling process that directly converts these two polyester wastes into biodegradable thermoplastic poly(ether ester)s using poly(tetramethylene ether)glycol(PTMG).The synthesized series of poly((ET-co-BT)-mb-PTMG)(PEBTG)exhibit a maximum tensile strength of 68 MPa,with 85%weight loss after 20 weeks in composted soil.Techno-economic analysis and life cycle assessment indicate that PEBTG is more cost-competitive and environmentally beneficial than currently existing plastics derived from fossil fuels,such as polypropylene and polybutylene adipate terephthalate.Once de-risked,the proposed upcycling strategy for polymer waste can be extended to expedite the development of a sustainable plastic economy.
文摘This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.
基金Sponsored by the National Natural Science Foundation of China
文摘Two kinds of tough ductile heatresisting thermoplastic, namely bisphenol A polysulfone (PSF) and polyethersulfone (PES) were used to toughen thermoset epoxy resin. A systematic study on the relationship between the molecular weight and the terminal group of the thermoplastic modifier and the fracture toughness of the modified resin was carried out. The morphology of PSF modified epoxy resin was surveyed. With the same kind of PSF the structure of the epoxy resin and the toughening effect of PSF was also investigated. The fractography of PSF, particle modified epoxy was examined in detail with SEM. The contribution of every possible energy absorption process has been discussed. Crack pinning mechanism seems to be the most important toughening mechanism for tough ductile thermoplastic PSF particle modified epoxy system.
基金This work was financially supported by the National Natural Science Foundation of China (No. 20174038).
文摘Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer or using theμTM method. By repeated molding, crossed structures were produced with a stamp prepared only with lines. The processingvariables including the softening temperature of the polymers and heating time were discussed. The result shows that theoptimal molding temperature is preferably slightly higher than the melting temperature of the thermoplastic polymers, atwhich polymers are in the critical states of being melted. This method can be applied to many polymers except those with high softening temperatures or high rate of shrinkage upon temperature change.
文摘The stabilization of vibration amplitude is an important factor for assuring welding quality. In this paper, the electric parameter for monitoring the output vibration amplitude of the transducer is determined by the analysis of electromechanical analogy,and matching circuits of constant current for the ultrasonic transducer are analyzed and compared. Series matching circuit is designed and analyzed using the method of impedance transformation. The output vibration amplitude of the transducer can be kept constant when the value of electric parameter for the matching circuit is chosen reasonably. The results of analysis is verified by technological experiments.
基金This work was finacially supported by the National Key Research and Development Program of China(No.2017YFA0403103)the Key Programs of the Chinese Academy of Sciences(No.ZDRW-CN-2018-2)the Youth Innovation Promotion Association CAS(No.2018040).
文摘Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.
文摘The recovery of thermoplastics has a major impact on our cities,both in terms of the environmental impact of waste disposal and the economic impact of its use in construction materials.The aim of this study is to manufacture bricks from recycled thermoplastics,more specifically low-density polyethylene(LDPE)packaging from households and landfill sites in the 9th arrondisse-ment.The technological evolution that humanity has undergone in recent years has made a wide variety of building materials available,and the use of earth as a material will make use of certain secondary products known as ad-ditives.These additions may be of mineral,animal or vegetable origin,and also of low purchasing power,but create a very strong bond once they are combined.The main aim of the present work is to contribute to the character-ization of bricks produced from thermoplastics and a soil sample taken from the bank of the Chari at Toukra in the 9th arrondissement of the capital,which are resistant to natural hazards such as bad weather and flooding,which al-ways cause enormous losses with each passing season.The results of the vari-ous tests carried out show that the material can help to overcome not only the lack of mechanical strength,but also the impermeability that is the cause of the deterioration and ruin of the building in clay without any addition modi-fying its properties.
文摘Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although significant attention has recently been given to recycling various waste materials into concrete,studies specifically addressing thermoplastic recycled aggregates are still trending.This underscores the need to comprehensively review existing literature,identify research trends,and recognize gaps in understanding the mechanical performance of thermoplastic-based recycled aggregate concrete.Accordingly,this review summarizes recent investigations focused on the mechanical properties of thermoplastic-based recycled aggregate concrete,emphasizing aspects such as compressive strength,tensile behavior,modulus of elasticity,and durability characteristics.The primary aim is to consolidate scattered research findings,identify key parameters influencing mechanical behavior,and propose future research directions.Understanding the influence of recycled thermoplastic aggregates on concrete performance significantly supports sustainable construction practices by reducing dependency on virgin aggregates and mitigating environmental impacts associated with waste disposal.In addition,assessing mechanical performance contributes to confidence in the practical application,encouraging the broader adoption of thermoplastic-based recycled aggregate concrete in construction projects.Through this critical synthesis,the review guides researchers and industry practitioners toward informed decisions on the feasibility and reliability of integrating thermoplastic waste into concrete,thereby promoting sustainable infrastructure development.
基金financially supported by the National Natural Science Foundation of China(Nos.52263010 and 52372188)2023 Introduction of studying abroad talent program,Henan Provincial Key Scientific Research Project of Collegesand Universities(No.23A150038)+1 种基金Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National students'platform for innovation and entrepreneurship training program(No.201910476010).
文摘Thermoplastic polyurethane(TPU)consists of a hardsegment and a soft segment,where the former affords mechanical strength and thermalstability,while the latter provides a possibility of good ionic conductivity by promoting dissociation of ions from the lithium salt.Thus,TPU attracts a wide interest recently as a promising polymer electrolyte for solid-state lithium batteries.However,the relatively low ionic conductivity of TPU still restricts its actual applications due to the aggregation of polymer chains,which greatly reduces the dissociation of lithium salts.Herein,a strategy to address this challenge was adopted by in situ polymerization poly(ethylene glycol diacrylate)(PEGDA)in fully dispersed TPU.Hence a stretchable solid-state electrolyte(denoted as TELL and the contrast sample was denoted as TLL)with high ionic conductivity of 7.18×10^(-4) S/cm was obtained at room temperature.The Li^(+)transference number is 0.85 in Li|TELL|Li cell and can stably undergo charge-discharge cycles for 1400 h at a current density of O.1 mA/cm^(2),while the contrast sample is short-circuited after 634 h of cycling.The LiFePO_(4)|TELL|Li cell achieves a capacity retention of 78.93%after 200 cycles at 2 C.The LiFePO_(4) TLL Li cellonly gains the capacity retention of 51.9%after 50 cyclesat the same current density.So,the method adopted here may provide a new approach to realize a flexible solid-state electrolyte with high ion-conductivity.
文摘The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature(UCST)or lower critical solution temperature(LCST)were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window.We found that the phase separation time/temperature relationship follows the simple Arrhenius equation.The cure-induced phase separation activation energy E_(a)(ps)generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time.We also found that E_(a)(ps)is insensitive to TP content,TP molecular weight and curing rate,but it changes with the cure reaction kinetics and the chemical environment of the systems.With the established phase separation time-temperature dependence relation,we can easily establish the whole cure time-temperature transformation(TTT)diagram with morphology information which is a useful map for the TP/TS composites processing industry.
基金supported by a grant from the Ministry of Research, Innovation and Digitization, UEFISCDI, Grant Nos. PN-IIIP2-2.1-PED-2021-1890, PN-IV-P6-6.3-SOL-2024-2-0254 and PNIV-P7-7.1-PTE-2024-0517, within PNCDI Ⅳ.
文摘This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Deposition Modeling(FDM)technology,highlighting the immense potential of this innovative approach.The use of FDM additive manufacturing technology to print gun propellants is a significant advancement due to its novel application in this field,which has not been previously reported.Through this study,the potential of FDM 3D-printing in the production of high-performance energetic composites is demonstrated,and also a new standard for manufacturability in this field can be established.The thermoplastic composites developed in this study are characterized by a notably high energetic solids content,comprising 70%hexogen(RDX)and 10%nitrocellulose(NC),which surpasses the conventional limit of 60%energetic solids typically achieved in stereolithography and light-curing 3D printing methods.The primary objective of the study was to optimize the formulation,enhance performance,and establish an equilibrium between printability and propellant efficacy.Among the three energetic for-mulations developed for 3D printing feedstock,only two were suitable for printing via the FDM tech-nique.Notably,the formulation consisting of 70%RDX,10%NC,and 20%polycaprolactone(PCL)emerged as the most advantageous option for gun propellants,owing to its exceptional processability,ease of printability,and high energetic performance.
基金the National Natural Science Foundation of China(Grant No.52203037,52103031,and 52073107)the Natural Science Foundation of Hubei Province of China(Grant No.2022CFB649)the National Key Research and Development Program of China(Grant No.2022YFC3901902).
文摘Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic thermoplastic polyurethane/carbon nanotubes/graphene nanosheets flexible strain sensor (TCGS) hasbeen developed using a combination of micro-extrusion compression molding andsurface modification for real-time wireless detection of liquid leakage. The TCGSutilizes the synergistic effects of Archimedean spiral crack arrays and micropores,which are inspired by the remarkable sensory capabilities of scorpions. This designachieves a sensitivity of 218.13 at a strain of 2%, which is an increase of 4300%. Additionally, it demonstrates exceptional durability bywithstanding over 5000 usage cycles. The robust superhydrophobicity of the TCGS significantly enhances sensitivity and stability indetecting small-scale liquid leakage, enabling precise monitoring of liquid leakage across a wide range of sizes, velocities, and compositionswhile issuing prompt alerts. This provides critical early warnings for both industrial pipelines and potential liquid leakage scenariosin everyday life. The development and utilization of bioinspired ultrasensitive flexible strain sensors offer an innovative and effectivesolution for the early wireless detection of liquid leakage.
基金UR 4370 LERMAB is supported by a grant overseen by the French National Research Agency(ANR)as part of the“Investissements d’Avenir”program(ANR-11-LABX-0002-01,Lab of Excellence ARBRE)in the frame of the project“Woodstic”ICEEL for the financial in the frame of the project“BoisPlast”(CARN 001301).
文摘Bio-based thermoplastic film from flax fiber and fatty acid(FA)was obtained using trifluoroacetic anhydride(TFAA)as an impelling agent.Different quantities of TFAA/FA,size of flax fiber,and fatty acids were applied to investigate chemical structure in relation to the mechanical properties.Decreasing the quantity of TFAA/FA by almost half from 1:4 to 1:2.5(flax to TFAA/FA)only reduces by 22%the weight percent gain(WPG)and ester content and reducing flax fiber size slightly increases the WPG and ester content.All the treatments showed sig-nificant chemical structure modification,observed by FTIR and solid CP/MAS^(13)C NMR,confirming the presence of carbonyl ester groups and alkyl chains,in relatively similar intensities.The crystallinity index(CrI)of esterified flax was evaluated by comparing the signal of solid CP/MAS^(13)C NMR in crystalline and amorphous regions and CrI was higher in esterified flax using a lower quantity of reagent and longer fatty acid.Esterified flax in a high quantity of reagent showed ductile or flexible behavior.Decreasing the reagent to 1:2.5 significantly increases the tensile strength and Young’s modulus,and decreases the elongation at break,presenting more brittle and stiff material.Using flax fiber in the original size results in slightly higher tensile strength and Young’s modulus and slightly lower elongation than milled flax.The tensile strength and Young’s modulus of stearic acid esterified flax obtained in this research were higher than myristic acid and comparable to the polyethylene plastics-LDPE and HDPE.
基金funded by the Foundation for Assistance to Innovations,under the“Student Startup”competition(agreement No.3075ΓCCC15-L/99398 dated 03 October 2024).
文摘The use of wood-polymer composites(WPC)based on a polymer matrix and wood filler is a modern,environmentally friendly direction in material science.However,untreated wood filler exhibits poor adhesion to hydrophobic polymers due to its hydrophilic lignocellulose fibers.To address this,ozone treatment is employed to enhance compatibility,reduce water absorption,and regulate biodegradation rates.This study investigates the hypothesis that ozone modification of wood filler improves adhesion to thermoplastic starch,thereby enhancing the physico-mechanical properties and controlled biodegradation of WPCs under compost conditions.A compre-hensive analysis was conducted on composites containing untreated and ozonated wood flour,focusing on tensile strength,bending resistance,impact strength,and biodegradation kinetics.Results showed significant improvements in mechanical properties for modified composites:tensile strength increased by 20%-25%,bending resistance by 15%-30%,and impact strength by 15%-20% compared to untreated samples.The optimal composition identified contained 70% ozonated wood flour and 30% thermoplastic starch(70WF/30P),demonstrating excellent mechanical strength(flexural strength of 18-22MPa),complete biodegradation within 140 days,and operational stability.The study revealed correlations between surface modification,interphase interaction,and biodegradation kinetics,advancing fundamental knowledge of lignocellulosic filler modification methods.These findings are crucial for developing eco-friendly composite materials with applications in biodegradable packaging and agricultural products,offering both scientific insights and practical solutions for sustainable material development.
基金supported by the Aeronautical Science Foundation of China(Grant Nos.2024Z009052003,20230038052001 and 20230015052002)the Third Batch of Science and Technology Plan Projects in Changzhou City in 2023(Applied Basic Research,Grant No.CJ20230080).
文摘This paper presents the development of a thermoplastic shape memory rubber that can be programmed at human body temperature for comfortable fitting applications.We hybridized commercially available thermoplastic rubber(TPR)used in the footwear industry with un-crosslinked polycaprolactone(PCL)to create two samples,namely TP6040 and TP7030.The shape memory behavior,elasticity,and thermo-mechanical response of these rubbers were systematically investigated.The experimental results demonstrated outstanding shape memory performance,with both samples achieving shape fixity ratios(Rf)and shape recovery ratios(R_(r))exceeding 94%.TP6040 exhibited a fitting time of 80 s at body temperature(37℃),indicating a rapid response for shape fixing.The materials also showed good elasticity before and after programming,which is crucial for comfort fitting.These findings suggest that the developed shape memory thermoplastic rubber has potential applications in personalized comfort fitting products,offering advantages over traditional customization techniques in terms of efficiency and cost-effectiveness.
基金supported by the National Natural Science Foundation of China(No.52173070).
文摘Electromagnetic pollution is becoming significantly serious.Therefore,it is critical to prepare the advanced electromagnetic interference(EMI)shielding materials with thinness,flexibility and high mechanical strength.Herein,the copperbased metal-organic framework(MOF-Cu)and polyethyleneiminemodified ammonium polyphosphate(PEI-APP)were successfully synthesized.The flame-retardant thermoplastic polyurethane(TPU)composite was successfully prepared by compounding MOF-Cu and PEI-APP.The Cotton@PDA@MXene composite was fabricated via a sequential loading process of polydopamine(PDA)and MXene onto cotton fabric.Then,the multilayer TPU composites were prepared by layer-by-layer hot-pressing.The TPU/9PAPP/1MOF/C-3PM composite exhibited exceptional EMI effectiveness of 20.5 dB in X-band and 23.0 dB in K-band,exceeding commercial standards.The TPU/9P-APP/1MOF/C-3PM composite also demonstrated significantly enhanced flame retardancy.Compared with pure TPU/Cotton sample,the peak heat release rate,total heat release and total smoke release of TPU/9PAPP/1MOF/C-3PM composite decreased by 40.7%,31.1%,and 33.3%,respectively.Furthermore,the thickness of the multilayer TPU composites was only 1 mm,demonstrating excellent flexibility.As the outer encapsulation material,TPU endowed the multilayer TPU composites outstanding durability and effectively addressed the common issues of fabric abrasion and conductive filler detachment.This study provides a novel strategy for preparing flexible electromagnetic interference shielding materials with superior flame retardancy.
基金financially supported by the CAS Project for Young Scientists in Basic Research(No.YSBR-023)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y2022068)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC06020301)。
文摘Adjusting the structure of the hard segment(HS)represents a key method for manipulating the mechanical properties of thermoplastic polyurethane(TPU).This study developed a novel molecular design strategy to tailor TPU's mechanical performance through altering the terminal diisocyanate structure of HS.The typical HDI-BDO based TPU was chosen as a model.Replacing HS's terminal HDI residues with aromatic PPDI,TODI,and MDI(the corresponding TPUs are named as 2P,2TO,and 2M,respectively)enabled broad tuning of TPU's Young's modulus while maintaining high tensile strength and elongation.Compared with linear PPDI and TODI,the bent and unsymmetrical MDI exhibits greater deviation from the central axis of the middle HDI-BDO segment,which reduces HS's capability of three-dimensionally ordered packing.Therefore,2P and 2TO show higher hydrogen bond content and crystallinity,stronger physical crosslinking network,and thus much higher Young's modulus than 2M(75.6 MPa).Besides geometric structure,π–πstacking between HS's terminal aromatic diisocyanates critically governs TPU's physical crosslinking network.In 2P,π–πstacking induces torsion of the middle HDI-BDO segment and disrupts the neighboring hydrogen bonds,leading to a dense network with fine hard blocks.In contrast,the lateral methyl groups in TODI hinderπ–πstacking,resulting in a sparse network with large hard blocks.Accordingly,2TO exhibits a higher Young's modulus(146.2 MPa)than 2P(124.0 MPa),but greater strain-rate sensitivity.
基金Open access funding provided by Ben-Gurion University.
文摘The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.
