白炭黑粒子对三元乙丙橡胶硫化性能、黏弹性及泡孔结构的影响

Effect of silica particles on vulcanization performance,viscoelasticity and cell structure of EPDM

采用4种不同种类的白炭黑粒子(A200,H2000,R812S,T36-5)分别作为三元乙丙橡胶(EPDM)的增强填料,并通过超临界CO_(2)发泡法制备具有微孔结构的EPDM泡沫材料。通过扫描电子显微镜和橡胶加工分析仪对不同白炭黑/EPDM基体的黏弹性、硫化性能及泡孔结构等进行测试和表征。结果表明:以气相法白炭黑(A200,H2000,R812S)作为增强填料的EPDM基体流变性能好,利于形成泡孔结构,且泡孔密度随交联度的提高而增加。而以沉淀法白炭黑T36-5作为增强填料的EPDM基体的模量和黏度过高,只在较窄的预硫化区间内形成泡孔结构。其中以白炭黑A200作为增强填料的EPDM基体在不损失良好流变性能的前提下仍能够获得较高的交联度,且A200能够提供更好的异相成核作用,明显提高泡孔密度,减小泡孔尺寸。

Four different types of silica particles(A200,H2000,R812 S,T36-5)were used as reinforcing fillers for EPDM to prepare microcellar EPDM foams by supercritical CO_(2).The viscoelasticity,vulcanization and cell structure of different silica were tested and characterized by scanning electron microscope and rubber processing analyzer.The results show that the EPDM matrix has good rheological property with fumed silica(A200,H2000,R812 S)as reinforcing filter,which is conducive to the formation of cell structure and the cell density is increased with the increase of the degree of crosslinking.The modulus and viscosity of the EPDM matrix with silica T36-5 matrix as the reinforcing filler by using precipitation method are too high,therefore the cell structure is formed only in narrow pre-vulcanization interval.Among them,the EPDM matrix with silica A200 as the reinforcing filler can obtain a high degree of cross-linking without losing good rheological properties,and A200 can provide better heterogeneous nucleation,and significantly improve cell density and reduce cell size.