串晶结构对自增强HDPE短期力学性能和耐慢速裂纹扩展性能的影响  

Influence of Shish-kebab Structure on the Shortdated Mechanical Property of Self-enhancement HDPE and Performance of Resist Slow Crack Growth

作　　者：曹建国[1,2] 高雪芹[2] 申开智[2] 

机构地区：[1]四川大学制造科学与工程学院,四川成都610065 [2]四川大学高分子科学与工程学院高分子材料工程国家重点实验室,四川成都610065

出　　处：《四川大学学报（工程科学版）》2012年第5期200-206,共7页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金重大资助项目(10590351);国家自然科学基金青年基金项目(50803038)

摘　　要：采用自行设计制造的动态保压(DPIM)装置和慢速裂纹增长监测装置,对通用级纯料HDPE5000S进行自增强和串晶对慢速裂纹增长影响研究。结果表明:动态保压试样有大量的串晶结构生成;动态保压试样的拉伸强度高达98.7 MPa,是静态试样24.2 MPa的4.08倍,提高了307.9%,实现了聚乙烯的自增强,动态试样拉伸强度的提高主要是由于有大量的互锁串晶结构形成和结晶度的提高共同所致。动态试样在拉应力是静态试样1.83倍的情况下,因慢速裂纹扩展而发生断裂的时间是静态试样的6.17倍。聚合物耐慢速裂纹增长的能力与聚合物的晶体结构有关,动态试样的串晶结构对慢速裂纹增长的阻止作用非常明显。串晶结构阻止慢速裂纹扩展的主要原因有:高强度的脊纤维晶断裂需克服很大的能量;串晶中片晶间互相紧密接触或重叠给慢速裂纹扩展带来较大的阻力;结晶度的提高。The self-enhancement of universal HDPE5000S and shish-kebab influence on slow crack growth were studied by using the self-designed and self-made dynamic packing injection molding（DPIM） equipment and slow crack growth monitor device.Testing results showed that dynamic samples engender lots of shish-kebab structure.Tensile strength of dynamic samples reaches to 98.7 MPa that is 4.08 times one（24.2 MPa） of static samples and increased 307.9% and realize polyethylene＇s self-enhancement.The mainly reasons that tensile strength of dynamic samples is largely enhanced are that a great deal of interlocking shish-kebab structure is formed and crystallinity is raised together.When tension stress of dynamic sample was 1.83 times that of static sample,the time of slow crack growth of dynamic sample was 6.17 times that of static sample.To a large extent,the capability of dynamic sample＇s resisting slow crack has something to do with the shish-kebab structure in it.

关 键 词：动态保压 慢速裂纹增长 自增强 串晶 

分 类 号：TQ320.66[化学工程—合成树脂塑料工业]