Study On Vulcanization And Properties Of POSS Modified CM Elastomer

Polyhedral oligomeric silsesquioxane(POSS)is a new type of organic-inorganic hybrid nanocrystals with excellent thermal stability,mechanical properties.Octavinyl silsesquioxane(OV-POSS)as a kind of POSS with functional groups,the research and application are of great value.POSS modified polymer composites are a new class of organic/inorganic hybrid materials that offer the advantages of both polymeric and inorganic materials,with better overall material properties.The amount of waste rubber production is increasing day by day.How to effectively use waste rubber has become an important issue concerning energy conservation and environmental pollution prevention.The main contents of this article include:1.Using vinyltriethoxysilane as raw material,anhydrous ethanol as solvent and concentrated hydrochloric acid as catalyst,octavinylsilsesquioxane was synthesized by hydrolysis and condensation reaction,and the structure of the product was characterized.In addition,we also preliminary the effects of reaction temperature,time and pH value on the yield of POSS were studied.It was concluded that the yield of OV-POSS was the highest when the reaction temperature was 40 ?,reaction time 5d and pH value 3.2.A series of CM/OV-POSS modified materials were prepared by blending.The vulcanization performance parameters,mechanical properties,thermo-mechanical properties,thermal stability properties,oxygen index of CM/OV-POSS modified materials and CM pure rubber were comparatively studied under the same vulcanization system.The results show that with the increase in the amount of OV-POSS in the modified rubber,the vulcanization rate of the modified material is increased,and the activation energy for curing is reduced accordingly.The tensile strength of the vulcanizate gradually increases,and the elongation at break decreases accordingly;the storage modulus and glass transition temperature of the vulcanizate increase accordingly;the thermal stability and limit oxygen index of the POSS?modified CM vulcanizate are both better than CM vulcanizate.3.Blend CM with recycled rubber(RR),using the peroxide DCP/TAIC curing system,a comparative study of the vulcanization performance parameters of CM and CM/RR blends,the mechanical properties,thermo-mechanical properties,heat aging and thermal extension properties of sulfides were compared,and observe its microstructure.The results showed that with the increase of the amount of recycled rubber,the vulcanization rate of the blends decreased and the vulcanization density decreased at the same time.The tensile strength and elongation at break of the sulfides decrease correspondingly with the increase of the reclaimed rubber content.With the addition of recycled rubber,two glass transition temperatures appear in the DMA curve,indicating that both CM and recycled rubber are not completely compatible.Scanning electron microscopy showed that compared with CM vulcanizate,blended vulcanizate had obvious holes after concentrated nitric acid etching.Heat aging and hot elongation tests showed that the performance of blended vulcanizate was inferior to that of CM vulcanizate and also showed that the crosslinked density of blended vulcanizate was inferior to that of CM vulcanizate.