Study On Anionic Synthesis,hydrogenation And Application Of Myrcene Copolymers

Filler dispersion is extremely important for improving rubber performance.The use of block copolymerization of bio-based monomer myrcene(My)and random copolymerization of carbon-carbon weak bond-containing para-(1,1-diphenylethyl)styrene(DPES)can significantly improve the filler dispersion of solution polymerized styrene-butadiene rubber.In order to investigate the synergistic effect of unsaturated carbon-carbon double bond and non-polar saturated long chain on filler dispersion,as well as the synergistic effect of carbon-carbon weak bond and non-polar unsaturated long chain on filler dispersion,we applied anionic polymerization to design and synthesize(Styrene-ran-butadiene)-b-myrcene copolymer(PSB-b-PMy),styrene-ran-butadiene copolymer(PSB),(styrene-ran-DPES-ran-butadiene)-b-myrcene copolymer(PSDB-b-PMy),etc.,and hydrogenated the former two,then studied the filler dispersibility and performance of carbon black/silica reinforced rubber prepared from above polymers.The main research contents and conclusions are as follows:(1)Hydrogenated styrene-butadiene copolymers(HPSB)with different hydrogenation degrees were designed and synthesized,then were reinforced with carbon black/silica to explore the effect of hydrogenation degree on the performances of carbon black and silica reinforced hydrogenated styrene-butadiene rubber.The results show that HPSB with hydrogenation degree of 42.0 %～98.4 % can be synthesized by changing the hydrogenation conditions,and Tg is slightly reduced after hydrogenation(-49.16 ℃～-43.62 ℃).Research on carbon black reinforced system shows that as the hydrogenation degree increases,the vulcanization time increases,the Payne effect is weakened,and the dispersibility of carbon black is improved to a certain extent;the elongation at break increases to 2.6times;the rolling resistance is increased.Research on the silica reinforcement system shows that as the hydrogenation degree increases,the vulcanization time of HSBR increases;the silica dispersibility of the vulcanizates is improved to a certain extent;the maximum of elongation at break exceeds3000%.(2)PSB-b-PMys were designed and synthesized,then were hydrogenated into HPSB-b-PMy with different hydrogenation degrees,which were reinforced with carbon black/silica respectively to explore the effect of hydrogenation degree on the performances of carbon black and silisca reinforced rubber(b-HSBMR).The results show that HPSB-b-PMy with hydrogenation degree of 42.0 %-97.3 % can be synthesized by changing the hydrogenation condition.Tg of PMy segment is basically unchanged at low hydrogenation degrees(42.0 %-65.9 %),but increased by 8～13.2 ℃ at high hydrogenation degree.Research on carbon black reinforced system shows that with the increase of hydrogenation degree,the vulcanization time increases;Payne effect is aggravated;the tensile strength is basically unchanged,and the elongation at break increases;rolling resistance increases.Research on silica reinforced system shows that with the increase of hydrogenation degree,vulcanization time of b-HSBMR increases;Payne effect of the vulcanizates gets stronger,and the flocculation degree of silica is more severe,indicating worse silica dispersion;There is little change in tensile strength,and the elongation at break is increased;the rolling resistance is increased.Based on the results of HSBR,excluding the influence of main chain saturation,the analysis results of dispersibility of carbon black or silica reinforced b-HSBMR system before and after hydrogenation show that the carbon-carbon double bond on the side chain is beneficial to the dispersion of the filler.Compared with HSBR,filler dispersion of b-HSBMR has significantly improved,indicating that non-polar saturated long chain is also beneficial to filler dispersion.In summary,the unsaturated carbon-carbon double bond and non-polar saturated long chain have a synergistic effect on the filler dispersion.(3)A variety of styrene-butadiene polymers containing DPES units and/or myrcene blocks were designed and prepared,then were reinforced with carbon black and silica respectively to explore the effects of DPES units and myrcene blocks on the performances of carbon black and silica reinforced styrene-butadiene rubbers.First,the copolymerization behavior of DPES and myrcene was studied.The results show that DPES-myrcene copolymer is a gradient polymer,therefore we designed and synthesized PSDB-b-PMy.The research results show that in the carbon black reinforced system,the introduction of 5 % DPES into PSB-b-PMy can further improve the dispersion of carbon black,wet skid resistance is enhanced,and the rolling resistance is reduced,indicating that the carbon-carbon weak bond and non-polar unsaturated long chain have a synergistic effect on the dispersion of carbon black;in silica reinforced rubber system,DPES is not conducive to the dispersibility,but the tensile strength is improved.The improvement of the filler dispersion in this system is mainly due to the introduction of the unsaturated long chain provided by myrcene.