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界面粘结对聚氯乙烯/丁腈橡胶共混物脆韧转变的影响 总被引:6,自引:1,他引:6
应用丙烯腈(AN)含量不同的丁腈橡胶(NBR)与聚氯乙烯(PVC)共混,研究了界面粘结对PVC/NBR共混物脆韧转变的影响.结果表明:当基体层度T相等时,过强的界面粘结,使PVC/NBR共混物的冲击强度降低,并且其产生脆韧转变的临界基体层厚度Tc减小.界面粘结对于聚合物共混物的增韧行为具有直接的影响.损伤区分析给出:随着界面粘结强度增大,空洞化过程受阻,减弱能量的耗散,并且不利于诱导剪切屈服损伤的产生,因而不利于增韧;但是界面粘强度过小,意味着共混物的相容性太差,致使分散相粒径过大,也不利于增韧.所以对增韧来讲,共混物的界面粘结强度存在一个最佳范围. 相似文献
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建立起激光强度调制法测量装置及其测量与数据处理方法,研究了VDF/TrFE铁电共聚物的极化分布和退极化过程.发现25μm厚的VDF(80)/TrFE(20)薄膜在距表面8μm左右薄层热电系数显示极大值,而12μm厚的则在中心处,两者的热电系数皆以两表面呈对称分布.在145℃热处理产生退极化.随着时间的增长,热电系数减小,退极化由试样的一面向另一面逐渐进行,2h后由强电场形成的极化基本消失.直流极化30μm厚的VDF(70)/TrFE(30)薄膜,热电系数分别在离两表面6,8μm处达恒定值,基本以两表面呈反
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The volume changes of rubber modified polymers under creep at room temperature were successfully used to characterize the toughening mechanisms of blends with brittle polymer matrices such as high impact polystyrene.This approach cannot be applied to pseudo-ductile polymers such as polypropylene and polyamide,because they are ductile when stretched at low speed at room temperature.Based on the time-temperature equivalence princi ple,the volume change at low temperature is proposed to characterize quantitatively the toughening mechanisms of polymer blends with ductile matrices,which is illustrated by applying this approach to rubber modified polypropylene 相似文献
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In situ compatibilization of low density polyehylene (LDPE) (30%) and nylon-6(70%)blends through one-step reactive extrusion using t-BuOOH as an initiator and low molec-ular weight interfacial agents as compatibilizers was studied. The compatibilizer containeda long chain bydrocarbon, double bond and two polar functional groups which was capableof reacting with both LDPE and nylon-6 in the presence of initiator to form a copolymerat the interface of the two polymer phases. The extruded blends exhibited significant en-hancement in their compatibility based on morphological, thermal analysis and mechanicalstudies. The effect of the hydrocarbon chain length and structure of the functional groupof the compatibilizer was also examined. It was found that blends prepared by using thecompatibilizer containing longer hydrocarbon chain and amide group had better mechanicalproperties. 相似文献
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聚合物共混物脆韧转变性能研究─—形态参数对聚氯乙烯/丁腈橡胶共混物脆韧转变性能的影响 总被引:1,自引:0,他引:1
研究了非晶的聚氯乙烯(PVC)/丁腈橡胶(NBR)共混物脆韧转变特性,主要包括形态参数─—分散相粒径(d)、体积分数()、特别是分散相粒径分布(б)对其脆动转变性能的影响.结果表明,当d<临界值(d)或>临界值()时,PVC/NBR产生脆韧转变.而且dC随。的增大而减小;随б的增大而增大。增大不利于增韧和脆韧转变的发生。也是影响聚合物共混物脆韧转变的重要形态参数,理论预示与实验结果很好相符.结果并给出PVC/NBR共混物的冲击韧性也是分散相粒间基体层厚度(T)的单参数函数.当T>T时,共混物为脆性;当T≤T时,共混物韧性剧增成为超韧合金.虽然,以分子链结构参数分类,PVC介于准韧性和脆性聚合物之间.结果证实,准韧性聚合物共混物脆韧转变的Tc判据仍然适用于PVC/NBR共混物. 相似文献
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PZT/P(VDF-TrFE)7030 0-3型复合材料的非等温结晶和居里相变行为 总被引:1,自引:0,他引:1
采用DSC研究了PZT P(VDF TrFE) 70 30复合材料的非等温结晶和居里相变过程 .结果表明 ,PZT粒子对共聚物基体的结晶行为 ,包括结晶温度、结晶速率和结晶度等影响不大 ;然而共聚物的居里相变过程则受到PZT粒子的影响 ,随PZT粒子含量的增大 ,共聚物基体的居里相变热焓与熔体结晶热焓的比值减小 ,而且其中对应从顺电性的高温相 (HT)转变为铁电性的过冷相 (CL)的相变热焓含量减小 ,意味着PZT粒子的存在能够抑制共聚物铁电晶体中旁式构象缺陷的形成 ,从而提高铁电晶体的完善度 相似文献