Study On The Structure And Properties Of Styrenebutadiene Rubber/Nanofiller Composites Based On Green Tires

The research and development of green tire is of great significance for reducing energy consumption and improving driving safety of automobiles.Styrene-butadiene rubber?SBR?is one of the main materials for tire tread rubber.SBR reinforced with silica has lower rolling resistance and better wet grip,which is in accordance with the requirements of green tire.However,there are many hydroxyls on the surface of silica,which makes silica hydrophilic.Therefore,the compatibility between polar silica and non-polar SBR is poor,resulting in the aggregation of silica in SBR matrix as well as the weak interaction between silica and SBR.In this thesis,the effects of ionic liquids and ionic liquids together with silane coupling agents on the structure and properties of SBR/silica composites were studied.Then,graphene oxide?GO?/carboxylated carbon nanotubes?CC?hybrid fillers were used as reinforcing fillers for green tire tread rubber,and the structure and properties of SBR/GO/CC composites were studied.The mechanical properties of SBR/nano-filler composites are mainly affected by the dispersion of fillers in SBR matrix of and the interaction between nano-filler and rubber chains.The ionic liquid 1-allyl-3-methylimidazolium chloride?AMI?used in this work could effectively promote the dispersion of silica in SBR matrix and enhance the interaction between silica and SBR.When AMI was used together with silane coupling agent bis[3-?triethoxysilane?propyl]-tetrasulfide?TESPT?,the mechanical properties of the composites were further improved,and it was aslo superior to SBR/silica composites using TESPT alone.In addition,carboxylated nitrile-butadiene rubber could effectively enhance the interface interaction between SBR and GO/CC hybrid fillers,which greatly improved the mechanical properties and thermal conductivity of SBR composites.The main work of this thesis is as follows.The effect of the amount of ionic liquid AMI on the structure and properties of SBR/silica composites was studied.When the amount of AMI was less than 2.5 phr?per hundred parts of rubber?,with the increasing use of the amount of AMI,the dispersion of silica in SBR matrix was gradually improved.When the amount of AMI was 2 phr,the total crosslinking density,tensile strength and stress at 300%strain of SBR/silica composites were increased by 55.0%,23.7%and 35.4%,respectively.On the basis of the above research,we introduced both ionic liquid AMI and silane coupling agent TESPT into SBR/silica system.Both TESPT and AMI could improve the dispersion of silica in SBR matrix,and the improvement effect was better than only using AMI or TESPT.Covalent bond interaction,hydrogen bond interaction and cation-pi interaction could be constructed between SBR matrix and silica.When TESPT dosage was 1 phr,with the increase of AMI dosage,the dispersion of silica in SBR matrix was gradually improved.When the amount of AMI was 1.5 phr,the total crosslinking density,tensile strength and stress at 300%strain of SBR/silica composites increased by281%,65%and 143%,respectively.To obtain stable GO/CC hybrid aqueous dispersion,GO was used to promote the dispersion of CC in water.After that,GO/CC aqueous dispersion was dripped into styrene-butadiene rubber/carboxylated nitrile butadiene rubber?mass ratio 95:5?latex mixture to prepare SBR/GO/CC composite with uniform filler dispersion.Hydrogen bond was formed between carboxyl group of carboxylated nitrile butadiene rubber and oxygen-containing functional groups of GO/CC hybrid fillers.Besides,the backbone of carboxylated nitrile butadiene rubber can be crosslinked to the backbone of styrene-butadiene rubber.When the dosage of hybrid fillers is GO 1 phr and CC 2 phr,the tensile strength and thermal conductivity of the composite were 19.3 MPa and 0.308W?m^-1?K^-1,respectively.Compared with vulcanized SBR,the tensile strength and thermal conductivity of the composites increased by 485%and 31%,respectively.