碳—碳键偶联共轭二烯—苯乙烯共聚物的制备、结构与性能

【作者】 徐日炜；

【导师】 焦书科；

【作者基本信息】 北京化工大学 ， 材料学， 2001， 博士

【摘要】 采用四氯化锡为偶联剂制得的锡偶联溶聚丁苯聚合物中含有锡-碳弱键，其易受剪切和热的作用断裂，导致分子量下降，力学性能也下降。在分析多种偶联剂偶联机理的基础上，本文采用含可聚合基团的亲电试剂作偶联剂，合成碳-碳键偶联溶聚丁苯共聚物，以改善其综合性能。 首先以丙烯酰氯(AC)、甲基丙烯酰氯(MAc)、甲基丙烯酸缩水甘油酯(GMA)、烯丙基氯(ALC)作偶联剂，偶联活性丁苯共聚物，发现仅有丙烯酰氯可以制备碳-碳键偶联的星形溶聚丁苯； 研究了丙烯酰氯偶联低分子量活性聚苯乙烯的反应机理，考察了偶联剂用量、线型聚合物分子量、溶剂的极性、不同链末端等对偶联反应的影响，发现丙烯酰氯(AC)所含的三个活性点均可以参与偶联反应，而且丙烯酰氯偶联活性聚合物的偶联机理与其用量密切相关； 以环己烷或抽余油为溶剂，考察了丙烯酰氯用量、线型聚合物分子量、偶联反应温度和时间、THF用量、不同链末端、单体浓度等对偶联反应的影响，确定了最佳的偶联反应条件是AC／BuLi=0.7～10(摩尔比)，偶联反应温度在50～60℃，偶联反应时间60min，TH/Li≤50，[M]=12％(w)；放大实验(2升反应釜)确定的偶联反应条件与小试基本一致； 采用IR和~1H-NMR对所得碳—碳键偶联溶聚丁苯共聚物和无规SIBR进行结构分析，结果表明苯乙烯单元在分子链上呈无规分布，所得聚合物组成比与实验设计值基本一致； 研究了碳—碳键偶联溶聚丁苯共聚物的力化学特性，发现素炼使C-C键偶联SSBR的分子链发生断链，导致分子量下降，聚合物的GPC曲线发生变化，高分子量级分减少，但是保持原有的位置，与锡偶联SSBR和ESBR相比，其素炼的分子量分布曲线变化更接近ESBR； 研究了C-C键偶联SSBR和SIBR的力学和动态粘弹性能，结果表明两者均具有优异的抗湿滑性能和低的滚动阻力，而且力学性能也较好，是一种高性能胎面胶；其硫化胶性能指标分别如下：SSBR：300％定伸17.7 MPa，拉伸强北京化』二大学俘d匕学位论文度22.gMPa，撕裂强度39.SMPa，伸长率500%，tan6(ooC)0.4782，tan6(60。C)0.1049;SIBR:300%定伸15.4 MPa，拉伸强度24.3MPa，撕裂强度40.4MPa，伸长率480%，tan6(ooC)0.701，tan6(60oC)0.1 17; 对比研究了末端改性对溶聚橡胶动态粘弹性能的影响，发现在聚合物分子量较低时，链末端改性可以改善橡胶的高温动态粘弹性能，tan6(60℃)明显下降，有助于降低滚动阻力;但在聚合物分子量较高时，橡胶的高温动态粘弹性能略有改善，tan6(60℃)略有下降，降低滚动阻力效果不明显。关键词:溶聚丁苯橡胶丙烯酞氯偶联剂苯乙烯一异戊二烯一丁二烯无规共聚橡胶偶联反应 阴离子聚合胎面胶抗湿滑性滚动阻力II更多还原

【Abstract】 Bond of the Sn-C in SSBR coupled with tetrachloride tin, namely tin coupled-SSBR, is easy broken by heat or shearing force, as a result the molecular weight of the Sn-SSBR were decreased, the mechanical properties were declined. In this paper, new diene-styrene copolymers coupled through carbon-carbon bond with novel coupling agent -acryloyl chloride ,were synthesized, and the mechanical properties and dynamic viscoelastic properties of the polymers were improved to some extent.Acryloyl chloride(AC), methacryloyl chloride, glycidyl methacrylate and allyl chloride were used as coupling agents for SSBR, and the star-polymers were prepared when the coupling agent was acryloyl chloride, while the others as coupling agents the obtained polymers mainly composed of the coupling of two prepolymers and with few star-like polymers.Mechanism of the reaction of living polystyrene with acryloyl chloride were investigated. It was found that the double bond, carbonyl bond, acyl chloride bond in the acryloyl chloride were all involved in the coupling reaction, and mechanism of the coupling reaction were effected by the amount of the acryloyl chloride used in the reaction.The effect of the amount of the acryloyl chloride, the molecular weight of living prepolymers, the time and temperature of coupling raction, the amount of THF, the monomer concentration, and different chain end group on the coupling reaction were studied. Cyclohexane and extracted oil as solvent, the optimism conditions of the coupling reaction were AC/BuLi=0.7~10 (mole ratio), temperature 50~60癈,time 60min,THF/BuLi<50 (mole ratio), [M]=12%(wt);the optimism coupling reaction conditions using 2 liter reactor were comply with above-mentioned conditions.The obtained SSBR and random SIBR coupled with acryloyl chloride respectivly were characterized by IR and ’H-NMR. The random distribution of the styrene unit in polymers were proved and the composition obtained by NMR were nearly as same as that of input ratio of the polymers.The mechanochemistry of SSBR coupled with AC during mastication were studied and the molecular chain were broken during mastication, as a result that the molecular weight of the polymer were declined ,the GPC curve were changed. But thebehavior of the SSBR coupled with AC were like that of ESBR to some extent other than Sn-SSBR.Mechanical and dynamic viscoelasticity of SSBR and SIBR coupled with acryloyl chloride were studied respectively. Both rubbers with excellent wet traction and low rolling resistance and good mechanical properties were confirmed and both of them are excellent tread rubbers. The typical example of SSBR coupled with AC were with modulus at 300% 17.7 MPa, tensile strength 22.9MPa, tear strength 39.5MPa, elongation 500%, tan 5 (0 ) 0.4782, tan 5 (60 ) 0.1049; The typical example of SIBR coupled with AC were modulus at 300% 15.4 MPa, tensile strength 24.3MPa, tear strength 40.4MPa, elongation 480%, tan 6 (0 0.701, tan 6 (60) 0. 117.The effect of chain end modification of SSBR on viscoelasticity were also studied. It was found that viscoelasticity of SSBR at high temperature were improved by chain end modification when the molecular weight of SSBR were relatively low (nearly 105), and tan 5 (60 ) were went down. And when the the molecular weight of SSBR were relatively high (nearly 2xl05), the improvement were less effective.更多还原