Study On Preparation And Properties Of Nitrile Rubber/SiO₂ Composites

Nitrile rubber(NBR) is widely used in fields of automotive industry, astronavigation,petroleum and chemical industry as universal sealing materials due to its good properties of tear resistant,wear resistant,oil immersion resistant and low compression set.With the development of petroleum and automotive industry, NBR used as sealing material was demanded for greater performances of mechanical properties,heat resistant,oil immersion resistant,and lower compression set.The improvement of NBR comprehensive performance was researched in this paper,and high performances NBR/SiO₂ composites were prepared.Main contents and results concluded as follows:(1) Using solid coupling agent Si69 in-situ modify SiO₂ to reinforce NBR,the influence of in-situ modification of SiO₂ with solid coupling agent Si69 on the properties of NBR was investigated and the applicability of solid coupling agent Si69 in-situ modification to different characteristic SiO₂ was discussed.The result shows that in-situ modification of SiO₂ with solid coupling agent Si69 could improve the dispersion degree and uniformity of SiO₂ and enhance the integrated properties of NBR.Rhenosin-42 could provide well cooperate effect with Si69 in the in-situ modification.Solid coupling agent Si69 in-situ modification hardly improve the dispersion of fumed SiO₂,indicated this method has applicability to different characteristic SiO₂.(2) The reinforcement of several typical fillers used alone or together with SiO₂ to NBR were researched,in order to find a suitable fillers cooperate well with SiO₂.The result showed that there has strong interaction between MMT and SiO₂ in processing.SiO₂ might had exfoliation effect to MMT,and the lamellar structure of MMT could help dispersing SiO₂ effectively;SiO₂ dispersed in polymer in nano scale,and might form bridge effect with MMT.As the results,SiO₂ and MMT showed good synergistic reinforcement to NBR.Analysis of X-ray diffraction(XRD) and scanning electronic micrograph(SEM) on NBR/SiO₂/MMT composite supported those points,but its mechanism needs more research.(3) Enhance the properties of NBR with HNBR,study the effect of HNBR on comprehensive performance of NBR.Research showed that there was good consistency between NBR and HNBR,but problems of composites structure and crosslinking consistency were existed caused by the differences of polarity,degree of unsaturation and active site.NBR/HNBR statically vulcanized blends has serious heterogeneity in physico-mechanical properties because of different crosslinking density.(4) Synthesize all the research results formulate simple NBR high-powered formula and using seal testboard test results to evaluate the industrialized application of this research.Seal testboard test results showed that the solid coupling agent Si69 in-situ modification and OMMT/ SiO₂ compound filler has well industrialized application future in NBR sealing material,especially the OMMT/SiO₂ compound filler revealed more apply predominance.Those two NBR reinforcement methods would get great application in NBR sealing material by more study.