Preparation Of Several Functionnaized Ssbr Using End-Capped Reactions Of Living Polymers

In recent years, the development of environmentally friendly high performance tires with low rolling resistance and wet skid resistance draws people’s attention. Polar modifier of styrene-butadiene rubber can enhances interaction between the rubber and filler and effectively reduces the content of free polymer chain ends, which contribute to the comprehensive properties of vulcanized rubber. Anionic polymerization is an efficient method for preparation of end-functionalized polymers. Reactive polymer can be obtained with n-butyl lithium as an initiator in cyclohexane, at presence of a polar modifier. By the reaction of reactive polymer with electrophile reagents, such as ethylene oxide, maleic anhydride, ethylene sulfide and3-chloropropyl trimethoxysilane, we can obtain corresponding functional ized polymers which were characterized by NMR、IR、GPC、MALDI-TOF MS and other means.Carboxyl terminated PS、PB and SSBR can be obtained by terminated reaction of ethylene oxide first and then maleic anhydride. This method is effective for avoiding the byproducts (alcohol structure and ketone structure). The yield of second-step capping reaction is over90%at20～60℃,with [MA]/[Li]=1.5;the extent of second-step capping reaction increases from82%up to95%with the ratio of [MA] and [Li] from1.0to3.0; the yield of second-step capping reaction decreases slightly with weight molecular increases. The yields of carboxyl terminated PB and SSBR are also above90%.Thiol-functionalized polymers can be obtained using the reaction of ethylene sulfide (ES) with poly sty rl lithium and poly(butadiene)lithium. Oxide sulfide oligomerization (about25.5%) was detected by MALDI-TOF MS, with a high yield about99%. Studies have shown that oligomer content increases with increase of temperature and [ES]/[Li]; a higher molecular weight has an adverse influence to oligomerization.Siloxane-capped SSBR can be obtained by reaction of reactive polymer with (3-Chloropropyl)trimethoxysilane. R values (R=[(3-Chloropropyl)trimethoxysilane]/[Li]) has a greater impact on the coupling reaction, and the increasing R will give a low content coupled polymer; Meanwhile coupling will increased at presence of H2O and higher temperature. Both direct drying at100℃in open mill and boiling before drying in the open mill, contribute to silicone hydrolysis and deacidification reaction, with increasing of the coupling ratio from10to15%.