Influence Of Filler Surface Modification And Filler Blend On Rubber Composites Structure And Properties

Filler dispersion in rubber matrix and filler-rubber interfacial interaction are crucial to rubber viscoelasticity. Under applications bearing cyclic deformation like tire, viscoelasticity of rubber materials determines application properties such as rolling resistance and wet skid resistance. Therefore, regarding to scientific researches and engineer applications, it is valuable to investigate impacts of filler dispersion and filler-rubber interfacial interaction on viscoelasticity of rubber materials. Based on this background, this dissertation discusses influences exerted by several filler modification and filler blending methods onto structures and properties of rubber composites, especially viscoelasticity and dynamic properties.(1) Aiming to investigate the individual impact of filler-rubber interaction onto dynamic properties of rubber composites by excluding influence induced by different filler dispersion, 4-(chloromethyl) phenyltrime-thoxysilane(CPT) and bis(trie-thoxysilylpropyl) tetrasulfide(TESPT) were used to modify SBR/SiO2 composites and composites with similar filler dispersion but different interfacial strength were obtained. Dynamic properties of rubber composites and filler-rubber interaction was correlated. Although SiO2 dispersion in rubber matrix was improved, weak interfacial effect and low crosslink density deteriorated dynamic properties of CPT-modified composites. Simultaneous improvement in dispersion and interfacial effect made TESPT ameliorate dynamic properties of rubber composites effectively. It indicates that interfacial effect plays a key role on improving dynamic properties of rubber composites.(2) Based on filler hierarchical structure and filler-rubber interfacial effect, relationships between CB and SiO2 blending and structure and properties of rubber composites were investigated. Storage modulus ′-strain γ curves of SSBR/CB/SiO2 composites were fitted by Kraus model and the deduced mass fractal dimension of filler network through Huber-Vilgis model was taken as an evaluation of filler cluster branching. When the weight ratio between CB and SiO2 equaled 9:1, filler dispersion was improved and branching of filler cluster was depressed. Therefore, reinforcement and dynamic properties of composites were ameliorated. When ratio of SiO2 increased continually, branching of filler cluster increased and interfacial effect deteriorated, worsening reinforcement efficiency and dynamic properties.(3) Simple and feasible dopamine in-situ polymerization was adopted to modify HNTs and SBR/CB/HNTs composites were processed through filler blending. Influences on filler dispersion, filler rubber interaction and viscoelasticity of rubber composites exerted by polydopamine were investigated. Polydopamine decrease surface energy discrepancy between HNTs and rubber matrix, making filler compatibility increase. However, the low grafting efficiency of polydopamine and the lack of effective interaction between rubber matrix, carbon black and modified HNTs made it hard to improve interfacial interaction and filler dispersion extraordinarily through this modification. Therefore, it is difficult to ameliorate reinforcement efficiency and dynamic properties of composites effectively through this method.