Anionic Design Synthesis And Performances Of ?-myrcene-based Diene Rubbers

With the incessant development of expressways and the increasing need for energy conservation in vehicles,improving the wet skid resistance of tires without the loss of their other properties,the solution to the "devil's triangle" of low roll resistance,high wet-resistance and high wear resistance for tire tread rubber has become a vital objective pursued by both academic and industrial sectors.However,the diminution of fossil reserves will not only cause irreversible environmental hazards and waste but also deprive our future generations of resources.Therefore,it is particularly important to develop sustainable bio-based polymers to replace petroleum-derived materials.?-Myrcene,a non-polar bio-based terpene monomer with bottlebrush structure,is of great significance for the development of high-performance bio-based rubber materials.A series of random,block and star-shaped integrated styrene-butadiene rubber introduced with myrcene were prepared by anionic polymerization.The properties of rubber such as viscosity,curing behavior,processing property,physical mechanical property and dynamic mechanical property were studied.The main contents and conclusions are as follows:1.Synthesis and performances of ?-myrcene-modified solution-polymerized styrene-butadiene rubber and carbon black-reinforced composites was studied.This paper described a method of successfully introducing bio-based monomer myrcene into styrene-butadiene rubber by anionic polymerization to solve the problem of fossil energy shortage and filler dispersibility.A series of styrene-myrcene rubber(SMR)and styrene-butadiene-myrcene rubber(SBMR)containing different myrcene contents with 100%conversion,high-molecular weight(150 000-200 000 Da),low polydispersity(1.09),and uniform compositions could be obtained.The results showed that when the content of myrcene in the copolymer increased from 10%to 70%,the structure content of 3,4-My in the terpolymer decreased from 81%to 32%;Tg decreased from-24.9? to-35.0?.The research of CB blending system showed that the non-polar side chain with isopropyl structure can significantly improve the dispersion of CB,and the wet skip resistance of rubber can be improved without damaging the rolling resistance.When the content of myrcene increased to 30%,vulcanized rubber had better mechanical properties,its tensile strength was 12.9 MPa,and the elongation at break was 621%.2.Synthesis and performances analysis of silica reinforced SSBR/silica nanocomposites was studied.A new strategy was proposed to improve the dispersion of silica in non-polar polymer matrix by introducing myrcene short bottlebrush chain.A series of random,block,star-shaped myrcene modified styrene-butadiene rubber was designed and synthesized.The results showed that myrcene bottlebrush structure,which was beneficial to spread and infiltrate on the surface of the filler,could significantly improve silica dispersibility.And the degree of improvement of silica dispersibility in rubber matrix can be ranked as follows:SBR(unmodified rubber)<SBR(75)+MR(25)(mechanical blending rubber)<r-SBMR(25)(random copolymerized rubber)<b-SBMR(25)(block copolymerized rubber)<s-b-SBMR(16)(star block copolymerized rubber).Moreover,compared with SSBR/silica composite,the rolling resistance of s-b-SBMR(16)/SiO2 reduced by 41.7%.The tensile strength of b-SBMR(34)/SiO2 increased by 77.8%,the tear strength increased by 20.8%,and elongation at break remained basically unchanged.3.Synthesis and property analysis of CB reinforced SSBR composites was studied.Based on the above research,a variety of hybrid arm integrated rubbers with myrcene bottlebrush structures and high styrene content in styrene butadiene chain segments were designed and synthesized.The results showed that different myrcene integration methods had different degrees of improvement on CB dispersion,meanwhile,the rolling resistance and wet slip resistance were both greatly improved,which could be ranked as b-SBMR>r-SBMR?s-b-SBMR>SBR,SBR>SBR+MR>r-SBMR>b-SBMR>s-b-SBMR,respectively.In the premise of the physical and mechanical properties were basically not affected,block integrated rubber has excellent comprehensive properties such as excellent processing performance,vulcanization behavior,low rolling resistance and high wet-resistance,which proves the advantages of short bottle brush structure in the design and application of rubber structure.