Preparation And Characterization Of In Situ Wet Graphene/polyisoprene Rubber Nanocomposites

In recent years,the high-performance graphene and its derived rubber materials have become the priority research areas of traditional rubber industry,on account of graphene's excellent mechanical properties,enormous specific surface area,superior thermal and electrical conductivity and so forth.It is noteworthy that the interfacial effect and even distribution between graphene and rubber matrix are the critical factors of realizing high-performance and functionalized rubber-based nanocomposites.Based on the idea that chemical modification and functionalization could enable graphene to distribute evenly in rubber-based nanocomposites,and there are superior interfacial interaction effect as well as compatibility between graphene and rubber matrix,the dissertation mainly focuses on designing and regulating the interfacial effect between graphene and rubber matrix,and conducting research on modifying the surface of graphene from two aspects,including the latex blending as well as in Situ Polymerization technique.Firstly,the hybrid particles were prepared by chemical bonds between graphene?rGO?and silica,and then hybrid filler was applied into rubber matrix.If silica and rGO were added directly into rubber matrix,served as the anisotropic filler,the rGOwas prone to be oriented by external forces and would result in severe calender effect.At the same time,it was hard to make a combination and produce synergistic effect between rGO and silica.The interfacial effect between the above two materials and rubber matrix was also unsatisfactory.However,the silica was zero-dimension material and owned the isotropic property,and the two-dimensional rGO and zero-dimensional silica were composited under the action of chemical bond.The distribution of zero-dimensional material on the surface of the two-dimensional material layer could increase the dispersion and interfacial action of both.?1?The dissertation utilized two different silane coupling agent to make surface functional modification on the rGO modified by surface active agent,and applied high-energy ball milling to prepare the hybrid particles of rGO and silica,and used the latex blend method to make rubber nanocomposites.The dissertation observed the dispersion and interfacial condition of hybrid particles in rubber,and maked research on the grafting properties of rGO/silica composite materials and the contribution of silica to the peeling condition of rGO sheet during ball milling.Meanwhile,the research also studied on the distribution,rheological properties,vulcanization properties,strain softening,Payne effect,interfacial interaction between rGO and rubber molecular chain.The results shows that the silane coupling agent containing-NH₂ group is favorable for preparing hybrid particles,and the silane coupling agent containing polysulfide-S4is more beneficial to mechanical properties.?2?Graphene oxide?GO?was gradually bridged to realize the surface functionalization,and the ultrasonic stripping was used to introduce zero-dimensional material,silica,to intercalate graphene to produce hybrid particles.The dissertation investigated on the effect of composited silane coupling agent on the preparative performance of hybrid particles,the effect of the co-flocculation on preparing nano rubber composite materials,the application of the composite materials in the tire tread surface.Observed on the influence of the non-hybrid particles with different GO contents,crosslinking density,adhesive,rheological property,vulcanization property,strain softening and Payne on the properties of rubber nanocomposites.With the addition of a small amount of hybrid particles,the tensile strength,modulus and elongation at break of composites increased simultaneously.The composite containing 3wt%GO showed 9.47 times higher modulus at 200%strain and 1.36 times higher tensile strength compared with cured rubber.Fabrication of tyre-trade using only 10 phr of the composite containing 1wt%of GO not only decreases the carbon black?CB?content by 5 phr and NR by 10 phr but also increases wear resistance by 44.5%,wet skidding resistance by 14.6%and decreased the rolling resistance by5.1%.?3?The research on the micromechanics of hybrid particles,which was prepared by the compound of graphene surface modification and silica,in natural rubber.The present dissertation uses two different theories to study on the micromechanics of graphene rubber nanocomposites,including classic composite micromechanics and tube model theory,which is included in the tangled model of statistical mechanics.The results show that the tube model theory of statistical mechanics's entanglement model is much closer to the actual mechanical behavior of hybrid particles in natural rubber.Secondly,this research was designed to prepare graphene/Carbon Nanotubes/MgCl₂supported Ti-based Ziegler-Natta catalysts through the ball milling process,using the catalytic functionalization of nanoparticles to prepare highly active catalyst,and adopting in situ polymerization technique to make polyisoprene rubber chain graft onto nano filler surface.Through the regulation of structural properties of polyisoprene,the optimization of graphene/carbon nanotubes/polyisoprene's prepared reaction conditions,to realize even dispersion of graphene in the rubber matrix and enhance the adhesion between nano filler and rubber material.Finally,the research got Trans-1,4-isoprrene?TPI?nanocomposites with over 98%trans-1,4-chains content,and the activity of catalyst reached 239 gTPI/mmolTi·h.The thermal and electrical conductivity of subsequent TPI nanocomposites is superior.Especially,the thermal conductivity reached 0.321 W/mK.which is 65%higher than that of original TPI materials?0.194 W/mK?.Meanwhile,the research result shows that graphene/Carbon Nanotubes facilities the increase of?-form crystals,and the decrease or even vanish of?-form crystals.