Research Of Ultra-fine Full-Vulcanized Powder Rubber On The Modification Of Tread Compound

In recent years,the automobile industry of China is developing rapidly,for example,the number of cars increases faster and faster.The resulting energy consumption,environmental pollution and safety hazards have attracted great interest.Therefore,how to improve wet skid resistance of tires,wear resistance and reduce the rolling resistance of tire tread is becoming an important project.The ultra-fine full-vulcanized powdered rubber(UFPR)having special gradient cross-linked structure,is a kind of nano-sized rubber powder which is prepared by industrial technologies of radiation vulcanization of synthetic rubber latex and dry spraying.In this thesis,we studied the effect of ultra-fine full-vulcanized powdered carboxylated styrene-butadiene rubber(UFPCSBR),ultra-fine full-vulcanized powdered styrene-butadiene rubber(UFPSBR)and ultra-fine full-vulcanized powdered nitrile rubber on mechanical properties,wear properties,processing properties,dynamic mechanical properties of tread compound composite materials.Also we optimized the curing system of rubber composites,processing technology,and various UFPR loadings in order to achieve better performances of tyre tread.And followings are some research work we have done.(1)We studied the effect of three kinds of UFPR particles on tensile strength,tear strength,elasticity,temperature wear,wet skid resistance,rolling resistance,processing performance,dynamic mechanical properties and other properties of tread compound.And we selected the UFPSBR and UFPNBR as the suitable ones.(2)The research on UFPNBR/NR/SBR composites.The thermodynamic properties showed that UFPNBR can improve the wet skid resistance of UFPNBR/NR/SBR composites,while reducing the rolling resistance;The RPA analysis of tread composite materials showed that UFPNBR can reduce the internal friction of FPNBR/NR/SBR composites;In addition,UFPNBR also has a role of increasing the anti-aging properties of UFPNBR/NR/SBR composites.With the quantity of UFPNBR increasing,the retention properties after aging increased gradually,however,compression fatigue temperature and compression set of UFPNBR/NR/SBR composites are basically invariant.(3)The research on UFPSBR/NR/SBR composites.The thermodynamic properties showed that UFPSBR can improve the wet skid resistance of UFPNBR/NR/SBR composites;The RPA analysis of tread composites showed that UFPSBR can reduce the internal friction of FPSBR/NR/SBR composites;UFPSBR can also improve the anti-aging properties of UFPSBR/NR/SBR composites.With the UFPSBR loading increasing,the retention properties after aging increased significantly,and the dynamic fatigue temperature rise of UFPSBR/NR/SBR composites decrease while the mechanical properties of UFPSBR/NR/SBR composites decreased slightly.(4)To optimize the processing,curing system and the amount of UFPR of tread rubber composites,with the amount of sulfur is 1.9 phr.After optimization,at the case of premising to keep rolling resistance and wet skid resistance of tread composites,the tensile strength,tear strength of UFPNBR/NR/SBR increased in varying degrees,tensile strength increased by 4.5MPa nearly,the wear resistance is well improved;Tensile strength of UFPSBR/NR/SBR composites increased by 5.5MPa nearly,the wear resistance is improved significantly.When the amount of UFPSBR is 20 phr,the wear volume of UFPSBR/NR/SBR composites is reduced by about 2.5 times.Research results show that both UFPSBR and UFPNBR increase the anti-aging properties of UFPR/NR/SBR composites while reducing the internal friction of UFPR/NR/SBR composites,leading to prolonging the service life and reducing the heat build-up of tyre tread.On the other hand,the UFPSBR can improve the wet skid resistance of UFPSBR/NR/SBR composite while UFPNBR not only improve the wet skid resistance of UFPNBR/NR/SBR composite but also reduce the rolling resistance,which optimize the wet skid resistance and rolling resistance well.Above excellent performance of UFPR/NR/SBR composites indicates that the UFPR has good application tendency in the future development of tyre tread.