甲基丙烯酸锌增强弹性体的相态研究 II.硫化胶料(英文)

Morphology study on elastomers reinforced by zinc dimethacrylateII. In vulcanizates

利用扫描电子显微镜(SEM)和透视电子显微镜(TEM)研究了甲基丙烯酸锌增强多种弹性体(包括BR,SBR,EPDM,NBR,EPM,POE和HNBR)的微观相态结构。发现在各体系的硫化胶料中均存在两类基本分散结构:纳米分散结构和微米分散结构。其中纳米增强结构是在胶料过氧化物交联过程中由ZDMA原位聚合生成的;而微米结构就是残余的ZDMA颗粒。这两种结构的尺寸及相对含量因不同的复合体系而不同。对于BR和SBR体系,其微米分散结构较其他体系更多,且纳米分散结构的尺寸相对略小。而在EPDM,NBR,EPM,POE,HNBR中,微米分散结构较少,且纳米分散结构的尺寸相对较大。还研究了ZDMA颗粒的原生尺寸对硫化胶料的相态结构的影响,发现在POE体系,较大的ZDMA原生尺寸将造成其硫化胶料中微米分散结构的大量增多;而EPDM,EPM,NBR,HNBR胶料的相态则对ZDMA原生尺寸的变化不敏感。硫化胶料的微观相态的差异必将对其物理机械性能产生直接的影响。

The morphologies of various ZDMA-reinforced elastomers(including BR,SBR,EPDM,NBR, EPM, POE and HNBR) were studied by using SEM and TEM.It is shown that there are two essential dispersion structures in the vulcanizates of these systems: nano-scale dispersion structure and micron one.It is thought that nano-scale with strong reinforcing ability is formed by in-situ polymerization during peroxide curing process; while micron one without reinforcement for vulcanizates is the residual ZDMA particle.It is also found that the relative content and size of this two dispersion structures varies from different compound systems.For BR and SBR vulcanizates,there are more micron structures and the dimension of nano structure one is relatively smaller than those of other system.For EPDM,NBR,EPR,POE and HNBR vulcanizates,there is fewer microns structure and the dimension of nanometer one is larger slightly.The effect of size of original ZDMA particles on morphology of vulcanizate was also investigated.In POE system,ZDMA original particles with larger size lead to more micron dispersion structures in vulcanizate.However,there is no considerable influence of size of ZDMA particles on morphologies of EPDM,EPM,NBR and HNBR systems.The details for the formation of these structures are illustrated.These differences in morphologies directly impact on the mechanical properties of vulcanizates.