It remains challenging to synthesize supertough thermoplastic elastomers(TPEs)since the stretchability and tensile strength are mutually exclusive.Here,we report a one-pot strategy for the preparation of sustainable,t...It remains challenging to synthesize supertough thermoplastic elastomers(TPEs)since the stretchability and tensile strength are mutually exclusive.Here,we report a one-pot strategy for the preparation of sustainable,triblock polyester TPEs consisting of poly(L-lactide)(PLLA)hard segments and poly(ɛ-caprolactone)-co-poly(δ-valerolactone)(PCVL)soft segments.The TPEs were synthesized successfully with high stretchability(up to 2100%)and strong tensile strength(up to 71.5 MPa)without requiring specific functionalized groups by simply adjusting the polymer microstructures,which,in turn,exhibited a world’s record toughness of 445 MJ/m^(3).Systematic investigation revealed that the block-like,gradient microstructure of PCVL improved the ductility by providing a flexible elastic network and enhancing the tensile strength through strain-induced crystallization.The practicability of this strategy was well demonstrated by lifting a water tank over 30,000 times heavier than itself and easy scale-up experiments.展开更多
Abstract Biodegradable poly（ether-imide-ester） elasto- mers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N＇,N-bis（2-carboxyethyl）- pyromellitimide which was derived from pyrom...Abstract Biodegradable poly（ether-imide-ester） elasto- mers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N＇,N-bis（2-carboxyethyl）- pyromellitimide which was derived from pyromellitic dianhydride and glycine. The chemical structures, crystal- linities, thermal stabilities, mechanical properties, hydro- philicities and biodegradabilities of these elastomers were investigated. The hard segments of the linear aliphatic poly （ether-ester） exhibited monoclinic chain packing. Increas- ing the amount of aromatic bisimide moieties in the poly （ether-ester） reduced the crystallinity of the material and improved the thermal stability and tensile strength of the elastomers. In addition, introducing a suitable amount of aromatic bisimide moieties into the poly（ether-ester） backbones endowed the elastomers with improved biode- gradability but too many aromatic bisimide groups reduced the biodegradability of the elastomers.展开更多
The experiment of injection molding, Dais-simulating test, morphological structure investigation(Scanning Electron Microscopy, SEM),X-ray photoelectron spectroscopy(XPS)were performed on mini-automobile spherical seat...The experiment of injection molding, Dais-simulating test, morphological structure investigation(Scanning Electron Microscopy, SEM),X-ray photoelectron spectroscopy(XPS)were performed on mini-automobile spherical seat which was made of thermoplastic polyester elastomer(TPEE)and oiled polyoxymethylene(POM),respectively. The friction-wear properties between the frictionl pair of polymer spherical seat and metallic(iron)spherical pin were studied. The test results indicate that the antifriction property of TPEE is superior to that of POM, while its surface chemical effect is inferior to that of POM.展开更多
The hydrogen bond percentage and its temperature dependence of the three TPU samples synthesized from polytetrahydrofuran, 4,4'-diphenylmethane diisocyanate, N -methyl diethanol amine or 1,4-butane diol were stud...The hydrogen bond percentage and its temperature dependence of the three TPU samples synthesized from polytetrahydrofuran, 4,4'-diphenylmethane diisocyanate, N -methyl diethanol amine or 1,4-butane diol were studied by means of IR thermal analysis. The enthalpy and the entropy of the hydrogen bond dissociation were determined by the Van't Hoff plot.展开更多
This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works wer...This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works were conducted on the relationships between rheological, optical properties, morphology, mechanical properties, abrasion resistance and thermostability given. The results showed that the shear viscosity of SBS not obvious effect with TPU content. The optical properties of the SBS/TPU blend that its uniform transparency. The morphology characteristics indicating the phase diversion and the variation in the size of the SBS domains from large to small as the TPU contents increased, with heterogeneous domain dispersions. Additionally, the mechanical properties, abrasion resistance and thermal resistance are improved as the amount of added TPU is increased, suggesting that the blending of SBS with TPU is consistent with the compound rule.展开更多
For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial ...For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
A series of aliphatic biodegradable poly（ether-ester）s based on poly（butylene succinate）（PBS）as hard segment and poly（tetramethylene oxide）（PTMO,M_n=1 000 g/mol） as soft segment were synthesized.The composit...A series of aliphatic biodegradable poly（ether-ester）s based on poly（butylene succinate）（PBS）as hard segment and poly（tetramethylene oxide）（PTMO,M_n=1 000 g/mol） as soft segment were synthesized.The composition dependence of thermal behavior,morphology and mechanical properties was investigated by differential scanning calorimetry（DSC）,atomic force microscopy（AFM）,and tensile testing.The crystallization temperature（T_c） and melting temperature（T_m） of the PBS block within poly（ether-ester）s decrease steadily at first,but decrease sharply with PTMO content above 50 wt%.Two crystallization peaks were detected for PTMO in PBSPTMO60 sample,suggesting the occurrence of fractionated crystallization.The crystallization enthalpies（△H_c） and melting enthalpies（△H_m） of PBS block decrease at first,then increase as PTMO content increases further.AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased.Finally,the results of tensile testing show that the poly（ether-ester）s present the behavior of plastics when PTMO content is below 40 wt%,and of thermoplastic elastomers with PTMO content above 50 wt%.By varying the composition of copolymer,the aliphatic poly（ether-ester）s plastics,or especially biodegradable aliphatic poly（ether-ester）s thermoplastic elastomers can be obtained.展开更多
We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests ...We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests regarding UVC surface activation ofpolyamide fiber materials in air using low-pressure mercury lamps with 185 nm and 254 nm emissions are shown. The effect of irradiation on fiber strength was studied to find out suitable process parameters for providing the UVC treatment efficient but as gentle as possible to avoid negative effects on reinforcement properties. Application of a laboratory process for UVC pretreatment leads to significantly increased adhesion strength between the fibers and the melt processable elastomers on the base of TPA （polyamide） respectively TPU （polyurethane）.展开更多
Alumina nanoparticles were dispersed in poly(amide 12-b-tetramethylene oxide) copolymer through extrusion. The alumina particles were functionalized with 3-(2 trimethoxysilylethyl) cyclohexene oxide. The following PEB...Alumina nanoparticles were dispersed in poly(amide 12-b-tetramethylene oxide) copolymer through extrusion. The alumina particles were functionalized with 3-(2 trimethoxysilylethyl) cyclohexene oxide. The following PEBAX TM/ Al2O 3 proportions were prepared: 0.1, 1.0, 5.0, and 10.0% w/w. The thermal stabiity of the nanocomposites was evalu- ated by thermograviemtric analysis under N2 and was comparable to the neat PEBAXTM polymer. The thermo-oxidative degradation of the polymeric matrix by oxygen was strongly hindered by the functionalized alumina. The rule of mixture would predict that the thermal degradation should be strongly dominated by PEBAXTM matrix. Therefore, the physical mixture of PEBAXTM and silanized alumina should be almost as stable as pure PEBAXTM. However, the experimental results suggest that the nanocomposites are more stable than the mixture of their components. This stabilization effect is evident in the temperature range between 300?C and 400?C, in which the degradation of the PA12 block takes place.展开更多
Poly(decamethylene terephthalamide/decamethylene isophthalamide)-block-polyvinyl alcoho)(PA10 T/10 IPEG) copolymer/graphene oxide(GO) composites were prepared via in-situ melt polymerization and two different nano-fil...Poly(decamethylene terephthalamide/decamethylene isophthalamide)-block-polyvinyl alcoho)(PA10 T/10 IPEG) copolymer/graphene oxide(GO) composites were prepared via in-situ melt polymerization and two different nano-filler addition approaches were compared. The relationship between the micro-structure and performance of the elastomer composites prepared by one-step and two-step methods was explored. The results show that the two-step method significantly promoted the dispersion of the GO in a polymer matrix, and facilitated the grafting of more hard molecular chains. Thus, the elastic modulus and tensile strength of the nanocomposite have been significantly improved by the presence of GO. This was because of the strong interaction between the functional groups on the surface of the GO and the hard molecular chains. This would be also be favorable to load transfer across the interface. Additionally, the elongation at the break of composites increased by 10% with the addition of a small amount of GO(0.2% wt). This is because hard domains tend to be enriched on the surface of GO in composites and act as a lubricating layer at the interface between the GO and matrix, leading to increased deformation ability. This work provides an effective strategy to prepare elastomer composites with high strength and toughness.展开更多
A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis...A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis（hydroxyethyloxycarbonylamino） hexane （BHCH）, i.e. PrePBHCHs, were prepared through the self-transurethane polycondensation of BHCH. A poly（butylene adipate） prepolymer （PrePBA） with terminal HO-- groups was prepared and used as a polyester glycol. A series of TPEURs were prepared by the co-polycondensation of the PrePBHCHs with PrePBA at 170 ℃under a reduced pressure of 399 Pa. The TPEURs were characterized by gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile test. The TPEURs exhibited Mn up to 23300 g/mol, Mw up to 51100 g/mol, Tg ranging from -33.8 ℃ to -3.1 ℃, Tm from 94.3 ℃ to 111.9 ℃, initial decomposition temperature over 274.7℃, tensile strength up to18.8 MPa with a strain at break of 450.0%, and resilience up to 77.5%. TPU elastomers with good crystallization and mechanical properties were obtained through a non-isocyanate route.展开更多
Ethylene-methacrylate-glycidyl(EMG)copolymer is employed to strengthen polyethylene terephthalate(PET)/glass fiber(GF)blends.This paper starts from investigating the effects of various EMG contents on mechanical prope...Ethylene-methacrylate-glycidyl(EMG)copolymer is employed to strengthen polyethylene terephthalate(PET)/glass fiber(GF)blends.This paper starts from investigating the effects of various EMG contents on mechanical properties,thermal properties and fractured surface morphology of PET/GF blends.All of the above-mentioned properties own extreme limits of EMG concentration.The crystallization ability of the blends increases with an increment in EMG content,whereas the crystallinity keeps stable at a relatively high level of 0-20 wt.%EMG loading.The tension,bending and impact properties of PET blends are enhanced with the addition of a self-made three-dimensional hierarchical porous carbon sponge(3DC)based on an optimal additive amount.Results indicate that EMG possesses the capabilities of increasing the toughness of PET/GF blends remarkably and transforming the blends from brittle fracture to tough fracture.According to the results,the blends exhibit the best overall properties as the content of EMG reaches 10-15 wt.%.展开更多
Black phosphorus(BP), as one of the most promising fillers for flame retarding polymer, has been seriously limited in practical application, due to the agglomeration and poor structural stability challenges.Here, the ...Black phosphorus(BP), as one of the most promising fillers for flame retarding polymer, has been seriously limited in practical application, due to the agglomeration and poor structural stability challenges.Here, the BP was modified by MXene and polydopamine(PDA) via ultrasonication and dopamine modification strategy to improve the structural stability and dispersibility in the matrix. Then, the obtained(BP-MXene@PDA) nanohybrid was employed to promote the mechanical performance, thermal stability,and flame retardancy of thermoplastic polyurethane elastomer(TPU). The resultant TPU composite containing 2 wt.% of BP1-MXene2@PDA showed a 19.2% improvement in the tensile strength and a 13.8%increase in the elongation at break compared to those of the pure TPU. The thermogravimetric analysis suggested that BP-MXene@PDA clearly enhances the thermal stability of TPU composites. Furthermore,the introduction of the BP-MXene@PDA nanohybrids could considerably improve the flame retardancy of TPU composite, i.e., 64.2% and 27.3% decrease in peak heat release rate and total heat release, respectively. The flame-retardant mechanisms of TPU/BP-MXene@PDA in the gas phase and condensed phase were investigated systematically. This work provides a novel strategy to simultaneously enhance the fire safety and mechanical properties of TPU, thus expanding its industrial applications.展开更多
With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversi...With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversion,catalyst efficiency(CE),intrinsic viscosity([g])and insoluble content were studied.The copolymer was analyzed with Fourier transform-infrared(FTIR)and nuclear magnetic resonance(1H-NMR).Results showed that the optimal polymerization conditions were:He/Bt=0.25,temperature 40℃–50℃,Al/Ti=400–500,Ti/(Bt+He)=3x10-5-4x10-5,time 4 h.Intrinsic viscosity was found to increase with increasing Ti/(Bt+He)and decreasing Al/Ti and polymerization temperature.When the molar content of He,Al/Ti and polymerization temperature increased,the insoluble content in CH2Cl2 of copolymers decreased.When Ti/(Bt+He)and reaction time increased,the insoluble con-tent in CH2Cl2 of copolymers also increased.The crystal-lization and stereoregularity of poly(1-butene)decreased with the addition of He.展开更多
基金supported by the National Natural Science Foundation of China(grant no.22071077)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences(grant no.2019-16)to Y.Z.,(grant no.51525305)to Y.M.,and(grant no.51988102)to X.C.
文摘It remains challenging to synthesize supertough thermoplastic elastomers(TPEs)since the stretchability and tensile strength are mutually exclusive.Here,we report a one-pot strategy for the preparation of sustainable,triblock polyester TPEs consisting of poly(L-lactide)(PLLA)hard segments and poly(ɛ-caprolactone)-co-poly(δ-valerolactone)(PCVL)soft segments.The TPEs were synthesized successfully with high stretchability(up to 2100%)and strong tensile strength(up to 71.5 MPa)without requiring specific functionalized groups by simply adjusting the polymer microstructures,which,in turn,exhibited a world’s record toughness of 445 MJ/m^(3).Systematic investigation revealed that the block-like,gradient microstructure of PCVL improved the ductility by providing a flexible elastic network and enhancing the tensile strength through strain-induced crystallization.The practicability of this strategy was well demonstrated by lifting a water tank over 30,000 times heavier than itself and easy scale-up experiments.
文摘Abstract Biodegradable poly（ether-imide-ester） elasto- mers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N＇,N-bis（2-carboxyethyl）- pyromellitimide which was derived from pyromellitic dianhydride and glycine. The chemical structures, crystal- linities, thermal stabilities, mechanical properties, hydro- philicities and biodegradabilities of these elastomers were investigated. The hard segments of the linear aliphatic poly （ether-ester） exhibited monoclinic chain packing. Increas- ing the amount of aromatic bisimide moieties in the poly （ether-ester） reduced the crystallinity of the material and improved the thermal stability and tensile strength of the elastomers. In addition, introducing a suitable amount of aromatic bisimide moieties into the poly（ether-ester） backbones endowed the elastomers with improved biode- gradability but too many aromatic bisimide groups reduced the biodegradability of the elastomers.
基金FundedbyKeyScientificandTechnologicalProjectofHubeiProvince (No .96 1 0 2 1 70 94 )
文摘The experiment of injection molding, Dais-simulating test, morphological structure investigation(Scanning Electron Microscopy, SEM),X-ray photoelectron spectroscopy(XPS)were performed on mini-automobile spherical seat which was made of thermoplastic polyester elastomer(TPEE)and oiled polyoxymethylene(POM),respectively. The friction-wear properties between the frictionl pair of polymer spherical seat and metallic(iron)spherical pin were studied. The test results indicate that the antifriction property of TPEE is superior to that of POM, while its surface chemical effect is inferior to that of POM.
基金Supported by the Key Subject Construction Project of Shanghai Educational Com mittee(No. 13980 70 2 )
文摘The hydrogen bond percentage and its temperature dependence of the three TPU samples synthesized from polytetrahydrofuran, 4,4'-diphenylmethane diisocyanate, N -methyl diethanol amine or 1,4-butane diol were studied by means of IR thermal analysis. The enthalpy and the entropy of the hydrogen bond dissociation were determined by the Van't Hoff plot.
文摘This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works were conducted on the relationships between rheological, optical properties, morphology, mechanical properties, abrasion resistance and thermostability given. The results showed that the shear viscosity of SBS not obvious effect with TPU content. The optical properties of the SBS/TPU blend that its uniform transparency. The morphology characteristics indicating the phase diversion and the variation in the size of the SBS domains from large to small as the TPU contents increased, with heterogeneous domain dispersions. Additionally, the mechanical properties, abrasion resistance and thermal resistance are improved as the amount of added TPU is increased, suggesting that the blending of SBS with TPU is consistent with the compound rule.
基金This work was financially supported by the Chemistry and Chemical Engineering Guangdong Laboratory(Nos.2111018 and 2132012)Q.M.would like to express gratitude towards the Foreign Youth Talent Program(No.QN2022030008L)for their support.
文摘For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金Funded by the National Natural Science Foundation of China(No.50873071)the Teaching and Research Award Program for Outstanding Young Professors in Higher Education Institute,MOE,China
文摘A series of aliphatic biodegradable poly（ether-ester）s based on poly（butylene succinate）（PBS）as hard segment and poly（tetramethylene oxide）（PTMO,M_n=1 000 g/mol） as soft segment were synthesized.The composition dependence of thermal behavior,morphology and mechanical properties was investigated by differential scanning calorimetry（DSC）,atomic force microscopy（AFM）,and tensile testing.The crystallization temperature（T_c） and melting temperature（T_m） of the PBS block within poly（ether-ester）s decrease steadily at first,but decrease sharply with PTMO content above 50 wt%.Two crystallization peaks were detected for PTMO in PBSPTMO60 sample,suggesting the occurrence of fractionated crystallization.The crystallization enthalpies（△H_c） and melting enthalpies（△H_m） of PBS block decrease at first,then increase as PTMO content increases further.AFM has demonstrated that phase-separated morphology transforms from a phase of continuous hard matrix to one of continuous soft matrix containing isolated hard domain as PTMO content is increased.Finally,the results of tensile testing show that the poly（ether-ester）s present the behavior of plastics when PTMO content is below 40 wt%,and of thermoplastic elastomers with PTMO content above 50 wt%.By varying the composition of copolymer,the aliphatic poly（ether-ester）s plastics,or especially biodegradable aliphatic poly（ether-ester）s thermoplastic elastomers can be obtained.
文摘We report about current work which is aimed to improve the adhesion of melt processable elastomers onto relevant reinforcement materials by means of short wave UVC （ultraviolet C） light. Results of laboratory tests regarding UVC surface activation ofpolyamide fiber materials in air using low-pressure mercury lamps with 185 nm and 254 nm emissions are shown. The effect of irradiation on fiber strength was studied to find out suitable process parameters for providing the UVC treatment efficient but as gentle as possible to avoid negative effects on reinforcement properties. Application of a laboratory process for UVC pretreatment leads to significantly increased adhesion strength between the fibers and the melt processable elastomers on the base of TPA （polyamide） respectively TPU （polyurethane）.
基金This work was supported by DGAPA-UNAM Grant IN202311CONACYT-CNPq Project 174378.
文摘Alumina nanoparticles were dispersed in poly(amide 12-b-tetramethylene oxide) copolymer through extrusion. The alumina particles were functionalized with 3-(2 trimethoxysilylethyl) cyclohexene oxide. The following PEBAX TM/ Al2O 3 proportions were prepared: 0.1, 1.0, 5.0, and 10.0% w/w. The thermal stabiity of the nanocomposites was evalu- ated by thermograviemtric analysis under N2 and was comparable to the neat PEBAXTM polymer. The thermo-oxidative degradation of the polymeric matrix by oxygen was strongly hindered by the functionalized alumina. The rule of mixture would predict that the thermal degradation should be strongly dominated by PEBAXTM matrix. Therefore, the physical mixture of PEBAXTM and silanized alumina should be almost as stable as pure PEBAXTM. However, the experimental results suggest that the nanocomposites are more stable than the mixture of their components. This stabilization effect is evident in the temperature range between 300?C and 400?C, in which the degradation of the PA12 block takes place.
基金the financial support from the Jiangsu Provincial Key Research and Development Program (Grant No. BE2019008)the Natural Science Foundation of China (Grant No. 51573103, 21274094 and 21304060)。
文摘Poly(decamethylene terephthalamide/decamethylene isophthalamide)-block-polyvinyl alcoho)(PA10 T/10 IPEG) copolymer/graphene oxide(GO) composites were prepared via in-situ melt polymerization and two different nano-filler addition approaches were compared. The relationship between the micro-structure and performance of the elastomer composites prepared by one-step and two-step methods was explored. The results show that the two-step method significantly promoted the dispersion of the GO in a polymer matrix, and facilitated the grafting of more hard molecular chains. Thus, the elastic modulus and tensile strength of the nanocomposite have been significantly improved by the presence of GO. This was because of the strong interaction between the functional groups on the surface of the GO and the hard molecular chains. This would be also be favorable to load transfer across the interface. Additionally, the elongation at the break of composites increased by 10% with the addition of a small amount of GO(0.2% wt). This is because hard domains tend to be enriched on the surface of GO in composites and act as a lubricating layer at the interface between the GO and matrix, leading to increased deformation ability. This work provides an effective strategy to prepare elastomer composites with high strength and toughness.
基金financially supported by the National Natural Science Foundation of China(Nos.21244006 and 50873013)
文摘A simple non-isocyanate route is developed for synthesizing crystallizable aliphatic thermoplastic poly（ester urethane） elastomers （TPEURs） with good thermal and mechanical properties. Three prepolymers of 1,6-bis（hydroxyethyloxycarbonylamino） hexane （BHCH）, i.e. PrePBHCHs, were prepared through the self-transurethane polycondensation of BHCH. A poly（butylene adipate） prepolymer （PrePBA） with terminal HO-- groups was prepared and used as a polyester glycol. A series of TPEURs were prepared by the co-polycondensation of the PrePBHCHs with PrePBA at 170 ℃under a reduced pressure of 399 Pa. The TPEURs were characterized by gel permeation chromatography, FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile test. The TPEURs exhibited Mn up to 23300 g/mol, Mw up to 51100 g/mol, Tg ranging from -33.8 ℃ to -3.1 ℃, Tm from 94.3 ℃ to 111.9 ℃, initial decomposition temperature over 274.7℃, tensile strength up to18.8 MPa with a strain at break of 450.0%, and resilience up to 77.5%. TPU elastomers with good crystallization and mechanical properties were obtained through a non-isocyanate route.
基金supported by the Special Support Plan for High-Level Talents of Guangdong Province(No.2017TQ04N840)Science and Technology Planning Project of Guangdong Province(No.2017A030313081).
文摘Ethylene-methacrylate-glycidyl(EMG)copolymer is employed to strengthen polyethylene terephthalate(PET)/glass fiber(GF)blends.This paper starts from investigating the effects of various EMG contents on mechanical properties,thermal properties and fractured surface morphology of PET/GF blends.All of the above-mentioned properties own extreme limits of EMG concentration.The crystallization ability of the blends increases with an increment in EMG content,whereas the crystallinity keeps stable at a relatively high level of 0-20 wt.%EMG loading.The tension,bending and impact properties of PET blends are enhanced with the addition of a self-made three-dimensional hierarchical porous carbon sponge(3DC)based on an optimal additive amount.Results indicate that EMG possesses the capabilities of increasing the toughness of PET/GF blends remarkably and transforming the blends from brittle fracture to tough fracture.According to the results,the blends exhibit the best overall properties as the content of EMG reaches 10-15 wt.%.
基金supported by the National Natural Science Foundation of China(No.21908031)Scientific Research Funds of Yunnan Education Department(No.2021Y111)。
文摘Black phosphorus(BP), as one of the most promising fillers for flame retarding polymer, has been seriously limited in practical application, due to the agglomeration and poor structural stability challenges.Here, the BP was modified by MXene and polydopamine(PDA) via ultrasonication and dopamine modification strategy to improve the structural stability and dispersibility in the matrix. Then, the obtained(BP-MXene@PDA) nanohybrid was employed to promote the mechanical performance, thermal stability,and flame retardancy of thermoplastic polyurethane elastomer(TPU). The resultant TPU composite containing 2 wt.% of BP1-MXene2@PDA showed a 19.2% improvement in the tensile strength and a 13.8%increase in the elongation at break compared to those of the pure TPU. The thermogravimetric analysis suggested that BP-MXene@PDA clearly enhances the thermal stability of TPU composites. Furthermore,the introduction of the BP-MXene@PDA nanohybrids could considerably improve the flame retardancy of TPU composite, i.e., 64.2% and 27.3% decrease in peak heat release rate and total heat release, respectively. The flame-retardant mechanisms of TPU/BP-MXene@PDA in the gas phase and condensed phase were investigated systematically. This work provides a novel strategy to simultaneously enhance the fire safety and mechanical properties of TPU, thus expanding its industrial applications.
基金supported by the National High-Tech Research and Development Program of China(863 Program)(Grant No.2006AA03Z546).
文摘With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversion,catalyst efficiency(CE),intrinsic viscosity([g])and insoluble content were studied.The copolymer was analyzed with Fourier transform-infrared(FTIR)and nuclear magnetic resonance(1H-NMR).Results showed that the optimal polymerization conditions were:He/Bt=0.25,temperature 40℃–50℃,Al/Ti=400–500,Ti/(Bt+He)=3x10-5-4x10-5,time 4 h.Intrinsic viscosity was found to increase with increasing Ti/(Bt+He)and decreasing Al/Ti and polymerization temperature.When the molar content of He,Al/Ti and polymerization temperature increased,the insoluble content in CH2Cl2 of copolymers decreased.When Ti/(Bt+He)and reaction time increased,the insoluble con-tent in CH2Cl2 of copolymers also increased.The crystal-lization and stereoregularity of poly(1-butene)decreased with the addition of He.
