高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (4): 673.

• 研究论文 • 上一篇    下一篇

酚醛树脂的增容作用对聚甲醛/丁腈橡胶共混物的韧性、结晶形态和亚微相态的影响

汪晓东, 张强   

  1. 北京化工大学材料科学与工程学院, 北京 100029
  • 收稿日期:2000-01-28 出版日期:2001-04-24 发布日期:2001-04-24
  • 通讯作者: 汪晓东(1967年出生),男,博士,副教授,主要从事聚合物共混改性的研究.
  • 基金资助:

    北京市科技新星计划资助

Compatibilizing Effect of Novolak on Toughness, Crystallite and Morphology of Polyacetal and Nitrile-Butadiene Rubber Blends

WANG Xiao-Dong, ZHANG Qiang   

  1. School of Materials Science & Engineering, Beijing University of Chemical Technology, Beijing 100029, China
  • Received:2000-01-28 Online:2001-04-24 Published:2001-04-24

摘要: 考察了酚醛树脂(Novolak)的增容作用对聚甲醛(POM)/丁腈橡胶(NBR)共混物的韧性、结晶形态和亚微相态的影响.实验结果表明,POM与NBR不相容,直接共混不能提高POM的韧性;添加Novolak后,当NBR质量分数为40%时共混物发生“脆-韧”转变.POM/NBR共混物中POM球晶尺寸大,易形成应力集中点,导致增韧效果不佳;Novolak可通过与POM的分子链间相互作用,改变POM分子链固有的规程和排列方式,使球晶显著减小.亚微相态显示,POM/NBR呈现“海-岛”结构相态,NBR在基体中分散性很差;添加Novolak可提高NBR在基体中的分散性;当NBR质量分数达到40%时,NBR在基体中呈现带状网络结构.网带结构能够终止受外力作用而在基体中产生的银纹和剪切屈服,增加了共混物的破裂能,从而使共混物的韧性显著提高.

关键词: 聚甲醛, 丁腈橡胶, 酚醛树脂, 韧性, 结晶形态, 亚微相态

Abstract: Compatibilizing effect of novolak on toughness, crystallite, and morphology of polyacetal(POM) and nitrile-butadiene(NBR) blends were investigated. It was found the POMand NBRwere immiscible system, and the compatibilization of POMand NBRcould be improved by addition of Novolak. As a result, Izod impact strength increased remarkably. The crystallite morphology of the blends under polarized light microscopy demonstrated that the size of spherulites of POMwas so large as to increase the brittleness of blends. The size of spherulites of POMcould be sharply reduced by mixing with Novolak, which suggested that the inner stress concentration in blends be diminished. POM/NBRblends exhibited a “sea island” morphology, where NBRwas the dispersed phase “sea” and POMwas continuous phase “island”. The morphology of POM/NBR/novolak(mass ratio 60/40/5) blends showed that there was not a “sea island” structure but a physical elastomer network. The elastomer network impeded the growth of craze and promoted the shear deformation of POMmatrix. As a result, a large amount of impact energy could be absorbed and the super toughness was thus obtained.

Key words: POM, NBR, Novolak, Toughness, Crystallite, Morphology

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