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
Block copolymers are marked by alternation of hard blocks and soft blocks, whereby the hard blocks are believed to form crystalline domains in non-crystalline matrix formed by aggregation of the soft blocks and a frac...Block copolymers are marked by alternation of hard blocks and soft blocks, whereby the hard blocks are believed to form crystalline domains in non-crystalline matrix formed by aggregation of the soft blocks and a fraction of the hard blocks escaping crystallization. On the basis of this two-phase model a number of studies has been made varying the nature and length of hard and soft blocks. After reviewing some papers published in this field, it may be concluded that the system in which properties of thermoplastic elastomers are exhibited can be generally divided into three catalogues, they are polyurethane, polyether-ester, polyesteramide elastomers. Structure-property relationship of these thermoplastic elastomers are given in this paper.展开更多
Hydrogen bond effects in thermoplastic polyurethane elastomers (TPU) with different chain extender structures and hard segment contents have been studied quantitatively by dynamic mechanical analysis. It has been foun...Hydrogen bond effects in thermoplastic polyurethane elastomers (TPU) with different chain extender structures and hard segment contents have been studied quantitatively by dynamic mechanical analysis. It has been found that the hydrogen bond effects in TPU decrease with the increase of temperature. The temperature dependence of hydrogen bonding in TPU’s can be described by the Arrhenius equation, and the activation energy of hydrogen bonding as well as the physical cross-link density have been calculated.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
Electrically conductive elastomer composites(CECs)with segregated networks of conductive nanofillers show high potential in stretchable strain sensors due to balanced mechanical and electrical properties,yet the sensi...Electrically conductive elastomer composites(CECs)with segregated networks of conductive nanofillers show high potential in stretchable strain sensors due to balanced mechanical and electrical properties,yet the sensitivity at low strain is generally insufficient for practical application.Herein,we report an easy and effective way to improve the resistive response to low strain for CECs with segregated network structure via adding stiff alumina into carbon nanostructures(CNS).The CEC containing 0.7 wt%CNS and 5 wt%Al_(2)O_(3) almost sustains the same elasticity(elongation at break of~900%)and conductivity(0.8 S/m)as the control,while the piezoresistive sensitivity is significantly improved.Thermoplastic polyurethane(TPU)composites with a segregated network of hybrid nanofillers(CNS and Al_(2)O_(3))show much higher strain sensitivity(Gauge factor,GF-566)at low strain(45%strain)due to a local stress concentration effect,this sensitivity is superior to that of TPU/CNS composites(GF-11).Such a local stress concentration effect depends on alumina content and its distribution at the TPU particle interface.In addition,CECs with hybrid fillers show better reproducibility in cyclic piezoresistive behavior testing than the control.This work offers an easy method for fabricating CECs with a segregated filler network offering stretchable strain sensors with a high strain sensitivity.展开更多
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.
文摘Block copolymers are marked by alternation of hard blocks and soft blocks, whereby the hard blocks are believed to form crystalline domains in non-crystalline matrix formed by aggregation of the soft blocks and a fraction of the hard blocks escaping crystallization. On the basis of this two-phase model a number of studies has been made varying the nature and length of hard and soft blocks. After reviewing some papers published in this field, it may be concluded that the system in which properties of thermoplastic elastomers are exhibited can be generally divided into three catalogues, they are polyurethane, polyether-ester, polyesteramide elastomers. Structure-property relationship of these thermoplastic elastomers are given in this paper.
文摘Hydrogen bond effects in thermoplastic polyurethane elastomers (TPU) with different chain extender structures and hard segment contents have been studied quantitatively by dynamic mechanical analysis. It has been found that the hydrogen bond effects in TPU decrease with the increase of temperature. The temperature dependence of hydrogen bonding in TPU’s can be described by the Arrhenius equation, and the activation energy of hydrogen bonding as well as the physical cross-link density have been calculated.
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.
基金The authors greatly acknowledge the financial support from the National Natural Science Foundation of China(No.51873126)the Fundamental Research Funds for the Central Universities,as well as the funding from the Science&Technology Department(No.2021YFH0123)of Sichuan Province.
文摘Electrically conductive elastomer composites(CECs)with segregated networks of conductive nanofillers show high potential in stretchable strain sensors due to balanced mechanical and electrical properties,yet the sensitivity at low strain is generally insufficient for practical application.Herein,we report an easy and effective way to improve the resistive response to low strain for CECs with segregated network structure via adding stiff alumina into carbon nanostructures(CNS).The CEC containing 0.7 wt%CNS and 5 wt%Al_(2)O_(3) almost sustains the same elasticity(elongation at break of~900%)and conductivity(0.8 S/m)as the control,while the piezoresistive sensitivity is significantly improved.Thermoplastic polyurethane(TPU)composites with a segregated network of hybrid nanofillers(CNS and Al_(2)O_(3))show much higher strain sensitivity(Gauge factor,GF-566)at low strain(45%strain)due to a local stress concentration effect,this sensitivity is superior to that of TPU/CNS composites(GF-11).Such a local stress concentration effect depends on alumina content and its distribution at the TPU particle interface.In addition,CECs with hybrid fillers show better reproducibility in cyclic piezoresistive behavior testing than the control.This work offers an easy method for fabricating CECs with a segregated filler network offering stretchable strain sensors with a high strain sensitivity.
