According to the great demand for the＂ green＂ plastics processing technology of the low energy consumption, high efficiency and environmental protection in plastics industry, the plastics processing method and techn...According to the great demand for the＂ green＂ plastics processing technology of the low energy consumption, high efficiency and environmental protection in plastics industry, the plastics processing method and technology based on the elongation rheology, with continuing evolution and innovation of the plastics plasticating and conveying method, are presented and researched on the basis of the plastics dynamic processing method arid equipment, and the plastics plasticating and conveying process in the vane extrusion system, the technical characteristics and the applications of vane plasticating and conveying technology are discussed. The research results show that compared with the conventional processing equipment, this new technology and equipment shows many outstanding advantages, such as shortening the thermo-meehanical history of the plastics processing by more than 50 % , reducing the energy consumption by 30 % or so, improving the mixing and blending effects, improving the quality of the products and the adaptability to materials, etc. , and it is found that the new technology and equipment has special superiority in the fields of the processing for material systems, such as the multiphase and multicomponent composite materials, the shear heat sensitive macromolecular materials, etc.展开更多
Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid...Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid copolymerization.The studies on homopolymerization showed that t-BuP2 was a particularly efficient catalyst for the polymerization of HEA at room temperature,giving an excellent monomer conversion.Throughout the polymerization,transesterification reactions were unavoidable,which increased the randomness in the structures of the resulting polymers.The studies on copolymerization showed that t-BuP2 could simultaneously catalyze the hybrid copolymerization via the combination of PTP and ROP at 25°C.During copolymerization,HEA not only provided hydroxyl groups to initiate the ROP ofε-caprolactone(CL)but also participated in the polymerization as a monomer for PTP.The copolymer composition was approximately equal to the feed ratio,demonstrating the possibility to adjust the polymeric structure by simply changing the monomer feed ratio.This copolymerization reaction provides a simple method for synthesizing degradable functional copolymers from commercially available materials.Hence,it is important not only in polymer chemistry but also in environmental and biomedical engineering.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
Correction to:Nano-Micro Lett.(2024)16:57 https://doi.org/10.1007/s40820-023-01288-y.Following publication of the original article[1],the authors reported that the order of the images in Figs.5 and 6 were reversed,the...Correction to:Nano-Micro Lett.(2024)16:57 https://doi.org/10.1007/s40820-023-01288-y.Following publication of the original article[1],the authors reported that the order of the images in Figs.5 and 6 were reversed,the positions of the images needed to be exchanged.Another mistake is that the author inadvertently copied the same image in Fig.2(f)with Fig.2(e).The correct Figs.2,5 and 6 have been provided in this correction.The original article[1]has been updated。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
Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesiz...Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesized an efficient blue-emissive polymer, abbreviated as PCB-TPE, using tetraphenylethene(TPE) as the main building block. PCB-TPE is thermally stable with a novel property of aggregation induced emission(AIE). The thermoresponsive property and mechanism of PCB-TPE were investigated. Its emission shows temperature-dependent features and reveals fine details in the thermal transitions from-10 °C to 60 °C. The polymer offers a platform for the development of efficient luminescent materials for further biological and optoelectronic applications.展开更多
The rheological behavior, thermal properties and foam morphology of linear polypropylene and long chain branching polypropylene prepared through UV irradiation reactive extrusion were studied by rheological test, melt...The rheological behavior, thermal properties and foam morphology of linear polypropylene and long chain branching polypropylene prepared through UV irradiation reactive extrusion were studied by rheological test, melt index test, DSC and supercritical carbon dioxide foaming technology. Rheological test and melt index test confirmed that under UV irradiation and extrusion, adding photo-initiator and cross- linking agent could achieve the purpose of branching, thus improved the melt strength of polypropylene effectively. The DSC results revealed that with the introducing of long chain branching, the melting range of the polypropylene broadened and the crystallization temperature increased. Owing to the introduction of long chain branches, polypropylene exhibited higher melt strength and strain hardening behavior. Compared with linear polypropylene, the foam morphologies of long chain branching polypropylene were more uniform.展开更多
Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of...Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.展开更多
The complexation of y-allyloxymethyl 18-crown-6(AC6) induced inferior mechanical and thermal properties of polyimide(PI) in spite of lowered dielectric constant(k). To solve this puzzle, tetrakis-(di methylsiloxy)-si ...The complexation of y-allyloxymethyl 18-crown-6(AC6) induced inferior mechanical and thermal properties of polyimide(PI) in spite of lowered dielectric constant(k). To solve this puzzle, tetrakis-(di methylsiloxy)-si lane was employed to crosslink the complex of AC6 and PI(AC6-PI) through hydrosilylation reaction. The crosslinked AC6-PI(SiAC-PI) composites possessed excellent mechanical and thermal properties as well as low k. The tensile strength and fracture energy of SiAC-PI were increased by 87% and 716%, and the glass transition temperature and 5% weight loss temperature elevated 14.5 ℃ and 38.8 ℃, respectively, compared with those of AC6-PI. The structure of SiAC-PI was characterized by FTIR spectra, crosslinked density and XRD diffraction patterns.展开更多
Halloysite nanotubes(HNTs)have been considered as a promising flame retardant fillers for polymers.In this work,the polyhedral oligomericsilsesquioxane(POSS)containing amino group was covalently grafted on the surface...Halloysite nanotubes(HNTs)have been considered as a promising flame retardant fillers for polymers.In this work,the polyhedral oligomericsilsesquioxane(POSS)containing amino group was covalently grafted on the surface of HNTs with 3-(2,3-epoxypropoxy)propytrimethoxysilane as a chemical bridge.The POSS modified HNTs(HNTs-POSS)dispersed uniformly in the thermoplastic polyurethane(TPU)matrix and endowed TPU nanocomposites with enhanced tensile properties and fire safety.Cone calorimeter tests revealed that the introduction of 2 wt%HNTs-POSS to TPU matrix remarkably reduced the peak of heat release rate(PHRR)and total heat release(THR)by 60.0%and 18.3%,respectively.In addition,the peak CO production rate and total smoke release(TSR)could be significantly suppressed by the addition of HNTsPOSS.The well dispersed HNTs in combination with the ceramified silicon network from the thermal decomposition of POSS contributed to the formation of a continuous and compact char layer,exhibiting a tortuous effect by inhibiting heat diffusion and evaporation of volatile gaseous.In addition,the released crystal water from HNTs could dilute the combustible volatiles and then decline the combustion intensity.The tensile tests demonstrated that introduction of 2 wt%HNTs-POSS would enhance the maximum stress of TPU nanocomposite with a slight decrease of elongation at break.The combination of HNTs and POSS through the construction of effective interfacial interactions provides a feasible way to effectively enhance the fire safety of TPU nanocomposites without scarifying ductility.展开更多
The high-efficiency fabrication of high-quality microcapsules containing epoxy is crucial to the further development of the potential practical self-healing epoxy systems based on microencapsulated two-part epoxy-amin...The high-efficiency fabrication of high-quality microcapsules containing epoxy is crucial to the further development of the potential practical self-healing epoxy systems based on microencapsulated two-part epoxy-amine chemistry.Herein,a novel microencapsulation technique based on non-equilibrium droplets via integrating electrospraying and interfacial polymerization(ES-IP)was established to efficiently microencapsulate epoxy monomers.The ES-IP technique,consisting of three continuous steps,i.e.electrospraying to massively generate droplets,enwrapping every single droplet through instant interfacial polymerization,and thickening shell at an elevated temperature,has great flexibility to regulate the microencapsulation process and the microcapsule quality.The fabricated core-shell structured epoxy microcapsules(Ep-MCs)were comprehensively characterized for their properties,showing that they have high cleanness with rare impurities,controllable and tunable size,good thermal stability and tightness,and high effective core fraction.The high-quality Ep-MCs were adopted to formulate a self-healing epoxy based on the microencapsulated epoxy-amine chemistry.The highest healing efficiency,in terms of the recovered mode I fracture toughness,of 110±17%was achieved after being healed at room temperature(~25℃)for 48 h.While the developed ES-IP technique facilitates the microencapsulation technique based on non-equilibrium droplets,the fabricated high-quality Ep-MCs greatly promote the further developments of the practical self-healing materials.展开更多
Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginner...Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginners,opensource codes are undoubtedly the best alternative to learning TO,which can elaborate the implementation of a method in detail and easily engage more people to employ and extend the method.In this paper,we present a summary of various open-source codes and related literature on TO methods,including solid isotropic material with penalization(SIMP),evolutionary method,level set method(LSM),moving morphable components/voids(MMC/MMV)methods,multiscale topology optimization method,etc.Simultaneously,we classify the codes into five levels,fromeasy to difficult,depending on their difficulty,so that beginners can get started and understand the form of code implementation more quickly.展开更多
Developing luminescent metal-organic frameworks(MOFs) capable of high-efficiency Fe^(3+)sensing has aroused great attraction in the fields of biology,chemistry,etc.However,previous solvothermal methods are limited by ...Developing luminescent metal-organic frameworks(MOFs) capable of high-efficiency Fe^(3+)sensing has aroused great attraction in the fields of biology,chemistry,etc.However,previous solvothermal methods are limited by organic solvent usage,time consuming,high pressure,and high-energy consumption.Herein,we propose the waste-toMOF strategy towards the scale-up production of La-MOF nanoparticles through the ball milling of recycled poly(-ethylene terephthalate)(PET) bottles and La(NO_(3))_(3)·_(6)H_(2)O.PET goes on alkaline hydrolysis to form 1,4-benzenedicarboxylic acid sodium salt(Na_(2)BDC) and ethylene glycol by ball milling.Subsequently,BDC reacts with La^(3+)to form La-MOF.The as-prepared La-MOF crystal nanoparticles possess a rod-like morphology with the size of few hundred nanometers.Additionally,La-MOF nanoparticles display high selectivity and sensitivity for Fe^(3+)detection.The quenching constant and limit of detection are 5.29×10^(3)(mol·L^(-1))^(-1) and 0.147 μmol·L^(-1),respectively,thus surpassing many advanced Fe^(3+) sensors.According to the result of density functional theory,the high Fe^(3+) detection performance of La-MOF is related to the complexing of Fe^(3+)with La-MOF,which leads to the gradual dissociation of the coordination bond between terephthalic acid and La^(3+).It is anticipated that the mechanochemistry milling-based wasteto-MOF strategy provides a new platform for the massive production of functional MOFs in a green manner.展开更多
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here...The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.展开更多
A model of the continuous melt transesterification process of bisphenol-A and diphenyl carbonate in a continuous stirred tank reactor to produce polycarbonate is presented. The model is developed by using the molecula...A model of the continuous melt transesterification process of bisphenol-A and diphenyl carbonate in a continuous stirred tank reactor to produce polycarbonate is presented. The model is developed by using the molecular species model of polycarbonate melt polycondensation and the modeling method of reactive flash. Liquid phase is treated as perfect mixed flow and the vapor phase is assumed following the ideal gas law. With this model, the continuous melt transesterification process of bisphenol-A and diphenyl carbonate is examined with respect to different orocess parameters.展开更多
Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring...Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM resonances.Herein,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors simultaneously.The structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene composites.Then,the result showed that CPP-SS can significantly improve theσof samples.Ultimately,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be surpassed.This work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.展开更多
A series of three cast polyurethane elastomers were prepared from 2,4-toluene diisocyanate (TDI) and 3,5-dimethyl-thioltoluenediamine (D MTDA) chain extender, with polyethylene adi-pate (PEA), polyoxytetramethylene gl...A series of three cast polyurethane elastomers were prepared from 2,4-toluene diisocyanate (TDI) and 3,5-dimethyl-thioltoluenediamine (D MTDA) chain extender, with polyethylene adi-pate (PEA), polyoxytetramethylene glycol (PTMG) and polycaprolactone (PCL) soft seg-ments. The polyol molecular weights em-ployed was 2000g/mol. The polyurethane elastomers were characterized by an elec-tronmechanical universal testing machine, an Akron abrasion loss tester, a LX-A Shore du-rometer, a rebound resilience equipment and a Dynamic- Mechanical analyzer. In addition, fractured surface of the polyurethane elas-tomers was investigated by a field emission scanning electron microscopy (SEM). The test results showed the PCL based elastomer ex-hibits the excellent tear and stress-strain properties that polyester based elastomers offer, while retaining superior compression set and resilience similar to polyether based elas-tomers. The static and dynamic properties of the PCL based elastomer were more suitable for dynamic applications. The SEM micro-graphs of all polyurethane samples indicated the existing of the microphase separation structure. Particles of the dispersed phase formed by the hard phase and crystalline part of the soft phase grows bigger with the in-creasing crystallinity of the soft segments. The hard domains are irregular shapes and with the sizes of a few micrometers.展开更多
Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilan...Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.展开更多
Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,th...Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films.In comparison to the dielectric constant of 2.9 of neat PI,PI with an interchain cross-linking structure containing 2 wt%1,3,5-tris(4-aminophenyl)benzene(TAPB)(interchain-PI-2)exhibited the reduced dielectric constant of 2.55 at 1 MHz.The PI films with intrachain crosslinking structure containing 2 wt%TAPB(intrachain-PI-2)exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of0.0075 at 1 MHz.It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport.The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced.Moreover,in contrast to interchain-PI films,the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased.This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.展开更多
It has been proved that introducing isocyanurate into polymer chains could improve the flame retardancy of polymers.We describe in this work the synthesis and the thermal property study of three thermoplastic polyisoc...It has been proved that introducing isocyanurate into polymer chains could improve the flame retardancy of polymers.We describe in this work the synthesis and the thermal property study of three thermoplastic polyisocyanurates,which are polyisocyanuratoamide(PICA-6),polyisocyanurato(ester amide)(PICEA-6)and polyisocyanurato(urea ester)(PICUE-6).These polymers show similar and improved thermal stability with the existence of isocyanurate rings.PICA-6 is more crystalizable than the rest two and the melting temperature is found to be around 240℃ but it still crystalizes slowly.For PICEA-6 and PICUE-6,only glass transition can be observed on the DSC traces.The glass transition temperature follows the order of PICA-6>PICEA-6>PICUE-6(101.9,77.9 and 28.7℃,respectively).展开更多
基金The National Nature Science Foundation of China (No.10872071 No.50973035+1 种基金 No.50903033)The National Technology R&D Program of China(No.2009BA184B06)
文摘According to the great demand for the＂ green＂ plastics processing technology of the low energy consumption, high efficiency and environmental protection in plastics industry, the plastics processing method and technology based on the elongation rheology, with continuing evolution and innovation of the plastics plasticating and conveying method, are presented and researched on the basis of the plastics dynamic processing method arid equipment, and the plastics plasticating and conveying process in the vane extrusion system, the technical characteristics and the applications of vane plasticating and conveying technology are discussed. The research results show that compared with the conventional processing equipment, this new technology and equipment shows many outstanding advantages, such as shortening the thermo-meehanical history of the plastics processing by more than 50 % , reducing the energy consumption by 30 % or so, improving the mixing and blending effects, improving the quality of the products and the adaptability to materials, etc. , and it is found that the new technology and equipment has special superiority in the fields of the processing for material systems, such as the multiphase and multicomponent composite materials, the shear heat sensitive macromolecular materials, etc.
基金financially supported by the Natural Science Foundation for Excellent Young Scholar of Jiangsu Province (No. BK20170056)the National Natural Science Foundation of China(No. 21304010)+1 种基金the Opening Project of Key Laboratory of Polymer Processing Engineering (South China University of Technology)Ministry of Education, and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid copolymerization.The studies on homopolymerization showed that t-BuP2 was a particularly efficient catalyst for the polymerization of HEA at room temperature,giving an excellent monomer conversion.Throughout the polymerization,transesterification reactions were unavoidable,which increased the randomness in the structures of the resulting polymers.The studies on copolymerization showed that t-BuP2 could simultaneously catalyze the hybrid copolymerization via the combination of PTP and ROP at 25°C.During copolymerization,HEA not only provided hydroxyl groups to initiate the ROP ofε-caprolactone(CL)but also participated in the polymerization as a monomer for PTP.The copolymer composition was approximately equal to the feed ratio,demonstrating the possibility to adjust the polymeric structure by simply changing the monomer feed ratio.This copolymerization reaction provides a simple method for synthesizing degradable functional copolymers from commercially available materials.Hence,it is important not only in polymer chemistry but also in environmental and biomedical engineering.
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.
文摘Correction to:Nano-Micro Lett.(2024)16:57 https://doi.org/10.1007/s40820-023-01288-y.Following publication of the original article[1],the authors reported that the order of the images in Figs.5 and 6 were reversed,the positions of the images needed to be exchanged.Another mistake is that the author inadvertently copied the same image in Fig.2(f)with Fig.2(e).The correct Figs.2,5 and 6 have been provided in this correction.The original article[1]has been updated。
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financially supported by the National Natural Science Foundation of China (No. 21374136)the Fundamental Research Funds for the Central Universities (Nos. 17lgjc03 and 18lgpy04)the Opening Project of the Key Laboratory of Polymer Processing Engineering (South China University of Technology, Ministry of Education, No. KFKT1703)
文摘Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesized an efficient blue-emissive polymer, abbreviated as PCB-TPE, using tetraphenylethene(TPE) as the main building block. PCB-TPE is thermally stable with a novel property of aggregation induced emission(AIE). The thermoresponsive property and mechanism of PCB-TPE were investigated. Its emission shows temperature-dependent features and reveals fine details in the thermal transitions from-10 °C to 60 °C. The polymer offers a platform for the development of efficient luminescent materials for further biological and optoelectronic applications.
基金Funded by the National Natural Science Foundation of China(No.51103091)Scientific Research Foundation for the Returned Overseas Chinese Scholars State Education Ministry(No.20101174-4-3)the Opening Project of the Key Laboratory of Polymer Processing Engineering,Ministry of Education,China and the Fundamental Research Funds for the Central Universities(No.2012ZM0074)
文摘The rheological behavior, thermal properties and foam morphology of linear polypropylene and long chain branching polypropylene prepared through UV irradiation reactive extrusion were studied by rheological test, melt index test, DSC and supercritical carbon dioxide foaming technology. Rheological test and melt index test confirmed that under UV irradiation and extrusion, adding photo-initiator and cross- linking agent could achieve the purpose of branching, thus improved the melt strength of polypropylene effectively. The DSC results revealed that with the introducing of long chain branching, the melting range of the polypropylene broadened and the crystallization temperature increased. Owing to the introduction of long chain branches, polypropylene exhibited higher melt strength and strain hardening behavior. Compared with linear polypropylene, the foam morphologies of long chain branching polypropylene were more uniform.
基金supported by National Natural Science Foundation of China(52103029 and 51903075).
文摘Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.
基金supported by the National Natural Science Foundation of China(No. 51573054)the Project for Science and Technology of Guangzhou (No. 201604016080)
文摘The complexation of y-allyloxymethyl 18-crown-6(AC6) induced inferior mechanical and thermal properties of polyimide(PI) in spite of lowered dielectric constant(k). To solve this puzzle, tetrakis-(di methylsiloxy)-si lane was employed to crosslink the complex of AC6 and PI(AC6-PI) through hydrosilylation reaction. The crosslinked AC6-PI(SiAC-PI) composites possessed excellent mechanical and thermal properties as well as low k. The tensile strength and fracture energy of SiAC-PI were increased by 87% and 716%, and the glass transition temperature and 5% weight loss temperature elevated 14.5 ℃ and 38.8 ℃, respectively, compared with those of AC6-PI. The structure of SiAC-PI was characterized by FTIR spectra, crosslinked density and XRD diffraction patterns.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0302300)the International Collaboration Programs of Guangdong Province(No.2020A0505100010)+4 种基金the Fundamental Research Funds for the Central Universities(No.2019MS062)the Natural Science Foundation of Guangdong Province(No.2021A1515012425)the Overseas Famous Scholar Funds of Guangdong Province(No.2020A1414010372)City University of Hong Kong(No.9678103)the Opening Project of Key Laboratory of Polymer Processing Engineering(South China University of Technology),Ministry of Education of China(No.KFKT1904)。
文摘Halloysite nanotubes(HNTs)have been considered as a promising flame retardant fillers for polymers.In this work,the polyhedral oligomericsilsesquioxane(POSS)containing amino group was covalently grafted on the surface of HNTs with 3-(2,3-epoxypropoxy)propytrimethoxysilane as a chemical bridge.The POSS modified HNTs(HNTs-POSS)dispersed uniformly in the thermoplastic polyurethane(TPU)matrix and endowed TPU nanocomposites with enhanced tensile properties and fire safety.Cone calorimeter tests revealed that the introduction of 2 wt%HNTs-POSS to TPU matrix remarkably reduced the peak of heat release rate(PHRR)and total heat release(THR)by 60.0%and 18.3%,respectively.In addition,the peak CO production rate and total smoke release(TSR)could be significantly suppressed by the addition of HNTsPOSS.The well dispersed HNTs in combination with the ceramified silicon network from the thermal decomposition of POSS contributed to the formation of a continuous and compact char layer,exhibiting a tortuous effect by inhibiting heat diffusion and evaporation of volatile gaseous.In addition,the released crystal water from HNTs could dilute the combustible volatiles and then decline the combustion intensity.The tensile tests demonstrated that introduction of 2 wt%HNTs-POSS would enhance the maximum stress of TPU nanocomposite with a slight decrease of elongation at break.The combination of HNTs and POSS through the construction of effective interfacial interactions provides a feasible way to effectively enhance the fire safety of TPU nanocomposites without scarifying ductility.
基金financially supported by the National Natural Science Foundation of China(No.51903090)the Science and Technology Program of Guangzhou(No.202102020632)Fundamental Research Funds for the Central Universities(No.2020ZYGXZR046)。
文摘The high-efficiency fabrication of high-quality microcapsules containing epoxy is crucial to the further development of the potential practical self-healing epoxy systems based on microencapsulated two-part epoxy-amine chemistry.Herein,a novel microencapsulation technique based on non-equilibrium droplets via integrating electrospraying and interfacial polymerization(ES-IP)was established to efficiently microencapsulate epoxy monomers.The ES-IP technique,consisting of three continuous steps,i.e.electrospraying to massively generate droplets,enwrapping every single droplet through instant interfacial polymerization,and thickening shell at an elevated temperature,has great flexibility to regulate the microencapsulation process and the microcapsule quality.The fabricated core-shell structured epoxy microcapsules(Ep-MCs)were comprehensively characterized for their properties,showing that they have high cleanness with rare impurities,controllable and tunable size,good thermal stability and tightness,and high effective core fraction.The high-quality Ep-MCs were adopted to formulate a self-healing epoxy based on the microencapsulated epoxy-amine chemistry.The highest healing efficiency,in terms of the recovered mode I fracture toughness,of 110±17%was achieved after being healed at room temperature(~25℃)for 48 h.While the developed ES-IP technique facilitates the microencapsulation technique based on non-equilibrium droplets,the fabricated high-quality Ep-MCs greatly promote the further developments of the practical self-healing materials.
基金supported by the National Key R&D Program of China[Grant Number 2020YFB1708300]the National Natural Science Foundation of China[Grant Number 52075184].
文摘Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginners,opensource codes are undoubtedly the best alternative to learning TO,which can elaborate the implementation of a method in detail and easily engage more people to employ and extend the method.In this paper,we present a summary of various open-source codes and related literature on TO methods,including solid isotropic material with penalization(SIMP),evolutionary method,level set method(LSM),moving morphable components/voids(MMC/MMV)methods,multiscale topology optimization method,etc.Simultaneously,we classify the codes into five levels,fromeasy to difficult,depending on their difficulty,so that beginners can get started and understand the form of code implementation more quickly.
基金financially supported by the National Natural Science Foundation of China (Nos.52373099,51903099 and 22102059)the 100 Talents Program of Hubei Provincial Government,Huazhong University of Science and Technology (Nos.3004013134 and 2021XXJS036)+4 种基金the Innovation and Talent Recruitment Base of New Energy Chemistry and Device (No.B21003)the Opening Project (No.KFKT2304) of the Key Laboratory of Polymer Processing Engineering (South China University of Technology)Ministry of Education,the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage(HUST)Ministry of Education (Nos.2022JYBKF01 and 2022JYBKF05)the National Innovation and Entrepreneurship Training Program for College Students (Nos.202310487109 and202310487110)。
文摘Developing luminescent metal-organic frameworks(MOFs) capable of high-efficiency Fe^(3+)sensing has aroused great attraction in the fields of biology,chemistry,etc.However,previous solvothermal methods are limited by organic solvent usage,time consuming,high pressure,and high-energy consumption.Herein,we propose the waste-toMOF strategy towards the scale-up production of La-MOF nanoparticles through the ball milling of recycled poly(-ethylene terephthalate)(PET) bottles and La(NO_(3))_(3)·_(6)H_(2)O.PET goes on alkaline hydrolysis to form 1,4-benzenedicarboxylic acid sodium salt(Na_(2)BDC) and ethylene glycol by ball milling.Subsequently,BDC reacts with La^(3+)to form La-MOF.The as-prepared La-MOF crystal nanoparticles possess a rod-like morphology with the size of few hundred nanometers.Additionally,La-MOF nanoparticles display high selectivity and sensitivity for Fe^(3+)detection.The quenching constant and limit of detection are 5.29×10^(3)(mol·L^(-1))^(-1) and 0.147 μmol·L^(-1),respectively,thus surpassing many advanced Fe^(3+) sensors.According to the result of density functional theory,the high Fe^(3+) detection performance of La-MOF is related to the complexing of Fe^(3+)with La-MOF,which leads to the gradual dissociation of the coordination bond between terephthalic acid and La^(3+).It is anticipated that the mechanochemistry milling-based wasteto-MOF strategy provides a new platform for the massive production of functional MOFs in a green manner.
基金the National Natural Science Foundation of China[grant numbers 52203038,52173036 and 52073107]the National Key Technology R&D Program of China[grant number 2022YFC3901904,2022YFC3901903,and 2020YFB1709301]the Central University Basic Research Fund of China[grant number 2021XXJS035].
文摘The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.
基金Supported by the National Natural Science Foundation of China (No.10472034, No.10590351) the Key Technologies R&DProgram of "the 10th Five Year Plan" of China (No.2001BA303B-02).
文摘A model of the continuous melt transesterification process of bisphenol-A and diphenyl carbonate in a continuous stirred tank reactor to produce polycarbonate is presented. The model is developed by using the molecular species model of polycarbonate melt polycondensation and the modeling method of reactive flash. Liquid phase is treated as perfect mixed flow and the vapor phase is assumed following the ideal gas law. With this model, the continuous melt transesterification process of bisphenol-A and diphenyl carbonate is examined with respect to different orocess parameters.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0302300)the China Postdoctoral Science Foundation(No.2019M652883)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110467)the financial support from the opening project of Guangdong provincial key laboratory of technique and equipment for macromolecular advanced manufacturing,South China University of Technology,China。
文摘Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM resonances.Herein,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors simultaneously.The structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene composites.Then,the result showed that CPP-SS can significantly improve theσof samples.Ultimately,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be surpassed.This work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.
文摘A series of three cast polyurethane elastomers were prepared from 2,4-toluene diisocyanate (TDI) and 3,5-dimethyl-thioltoluenediamine (D MTDA) chain extender, with polyethylene adi-pate (PEA), polyoxytetramethylene glycol (PTMG) and polycaprolactone (PCL) soft seg-ments. The polyol molecular weights em-ployed was 2000g/mol. The polyurethane elastomers were characterized by an elec-tronmechanical universal testing machine, an Akron abrasion loss tester, a LX-A Shore du-rometer, a rebound resilience equipment and a Dynamic- Mechanical analyzer. In addition, fractured surface of the polyurethane elas-tomers was investigated by a field emission scanning electron microscopy (SEM). The test results showed the PCL based elastomer ex-hibits the excellent tear and stress-strain properties that polyester based elastomers offer, while retaining superior compression set and resilience similar to polyether based elas-tomers. The static and dynamic properties of the PCL based elastomer were more suitable for dynamic applications. The SEM micro-graphs of all polyurethane samples indicated the existing of the microphase separation structure. Particles of the dispersed phase formed by the hard phase and crystalline part of the soft phase grows bigger with the in-creasing crystallinity of the soft segments. The hard domains are irregular shapes and with the sizes of a few micrometers.
基金Project(20574020) supported by the National Natural Science Foundation of ChinaProject(20061001) supported by the Opening Project of the Key Laboratory of Polymer Processing Engineering, Ministry of Education, ChinaProject (20060106-2) supported by Guangdong Key Projects
文摘Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.
基金financially supported by the National Natural Science Foundation of China(No.52103029)。
文摘Polyimide(PI)is widely used in high-frequency communication technology due to its exceptional comprehensive properties.However,traditional PI has a relatively elevated dielectric constant and dielectric loss.Herein,the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films.In comparison to the dielectric constant of 2.9 of neat PI,PI with an interchain cross-linking structure containing 2 wt%1,3,5-tris(4-aminophenyl)benzene(TAPB)(interchain-PI-2)exhibited the reduced dielectric constant of 2.55 at 1 MHz.The PI films with intrachain crosslinking structure containing 2 wt%TAPB(intrachain-PI-2)exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of0.0075 at 1 MHz.It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport.The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced.Moreover,in contrast to interchain-PI films,the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased.This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.
基金the financial supports to this work by the National Natural Science Foundation of China(Nos.21404040,21734004,51573061)the Fund of the Key Laboratory of Luminescence from Molecular Aggregates of Guangdong Province,Guangzhou 510640,China(South China University of Technology,No.2019B030301003)the Opening Project Funding of Key Laboratory of Polymer Processing Engineering(South China University of Technology),Ministry of Education,China(No.KFKT1702).
文摘It has been proved that introducing isocyanurate into polymer chains could improve the flame retardancy of polymers.We describe in this work the synthesis and the thermal property study of three thermoplastic polyisocyanurates,which are polyisocyanuratoamide(PICA-6),polyisocyanurato(ester amide)(PICEA-6)and polyisocyanurato(urea ester)(PICUE-6).These polymers show similar and improved thermal stability with the existence of isocyanurate rings.PICA-6 is more crystalizable than the rest two and the melting temperature is found to be around 240℃ but it still crystalizes slowly.For PICEA-6 and PICUE-6,only glass transition can be observed on the DSC traces.The glass transition temperature follows the order of PICA-6>PICEA-6>PICUE-6(101.9,77.9 and 28.7℃,respectively).
