Study On The Synthesis And Properties Of Silica Grafted Epoxidized Solution Styrene-butadiene Rubber By Wet Processing

As a kind of new type filler, silica can effectively improve the combustion of the fuel and the performance of wet skid resistance, and it is used by more and more widely in tread compound. Solution styrene-butadiene rubber(SSBR) has all kinds of outstanding properties which are suitable for tire tread. Solution styrene-butadiene rubber as tread rubber can take into account the rolling resistance, wet skid resistance of, wear resistance and durabilitybetter,so it is the ideal material of tread rubber. However, incompatibility between solution styrene-butadiene rubber and silica in the traditional mixing process exist,due to the fact that solution styrene-butadiene rubber has no polarity and silica of polarity is very large.That lead to decreasing of dispersion of filler. In this thesis,we attempt to improve the dispersion of filler and interaction between filler and matrix by introducing polar group onto molecular structure of SSBR through chemical reaction.Solution styrene-butadiene rubber was synthesized with n-BuLi as initiator,cyclohexane as solvent,THF as polar modifier,design of molecular weight as 20 million,and the quality ratio between styrene and butadiene is 1:4. Solution styrene-butadiene rubber(SSBR) was epoxidized in situ by using H2O2 and HCOOH as performic acid oxidation system. The grafting reaction was based on ring opening reaction between Si-OH of silica and epoxide group of ESSBR. The silica was grafted on ESSBR by covalent bonds. The modified material has a certain polarity due to the presence of Si-OH.The compatibility with the filler of SSBR was improved.Solution styrene-butadiene rubber(SSBR) was epoxidized in situ with reaction temperature as 40 ?,with reaction time as 1 hour,with glue solubility as 10 g / 100 mL cyclohexane,with amount ratio of reactants(H2O2:C=C: HCOOH) as 3:2:1.In order to prepare the rubber with the best comprehensive performance the grafting reaction was propessed. Epoxy degree of SSBR was controlled at around 4%. Reaction time of grfting was 2 hour, Dosage of silica was 0.2 g pre 100 mL glue.The structure of the modified material were characterized by GPC, FT-IR, 1H-NMR, SEM,TGA and DSC. The results showed that the graft ratio reached nearly 100%; the glass transition temperature increased 6.1 ?; the distribution of silica in rubber is more uniform due to improved compatibility between silica and rubber.After mixing we measured rubber Mooney viscosity,bound rubber content of rubber compound. After curing of modified we measured wear resistance, curing performance,physical and mechanical properties, dynamic mechanical properties and crosslinking density of vulcanized rubber. The experimental results show that after grafting-modification Mooney viscosity decreases; the wear resistance of rubber increases;crosslinking density increases,the scorch time and curing time of rubber extend, The tan? values of vulcanizates at 0?and 60? increase.