动、静态硫化(NR+SBR)/PE共混体系的结构与性能

STRUCTURE AND PROPERTIES OF(NR+SBR)/PE BLENDS WITH RUBBER CURED BY DYNAMIC OR STATIC METHOD

用TEM研究了(NR+SBR)/PE共混体系经动、静态硫化后的形态结构及其与力学性能的关系。未硫化和静态硫化体系的形态结构与其组成有关,均以含量大的组份为连续相;对动态硫化体系,当(NR=SBR)/PE<70/30时,均以PE为连续相,其性能主要依赖于构成连续相组份的性质。 动态硫化体系的T_g值低于静态体系,随PE组份含量的增加变化不大,而静态硫化体系的T_g值则随PE含量增加向高温方向迁移。用DSC测得动态硫化体系的结晶度比静态体系的大。前者的应力-应变性能也低于后者。

Morphology and mechanical properties of (NR+SBR)/PE blends with rubber uncured orfully cured by either dynamic or static vulcanization were studied by transmission and sca-nning electron microscopy. The results showed that in the case of non-vulcanization PEexisted as a dispersed phase at (NR+SBR)/PE ratio(w/w) of 70/30 and as a continuousphase with ratio ≤50/50. The blends obtained by static vulcanization had the same morphologyas the uncured blends. When the rubber was cured by the. dynamic method, PE always ex-isted as a continuous phase.The tensile strength of the (NR+SBR)/PE blends increased withincrease in PE content. The DSC and dynamic mechanical test results proved that method of rubber vulcaniza-tion was the prime factor responsible for the compatibility between blend components. Theblends cured by static vulcanization had higher tensile strength than those by the dynamicmethod. This is considered as due to the difference in interpenetration between rubber andPE molecules, the penetration bein g in a higher degree in the static than in the dynamicvulcanization.