【作者】 贾忠明；

【导师】 李杨； 张学全；

【作者基本信息】 大连理工大学 ， 高分子材料， 2009， 硕士

【摘要】 聚苯乙烯（PSt）因其具有优良的加工性能和力学性能而得到了广泛应用和迅速发展。通用PSt冲击强度较低,引入橡胶组分可改善其冲击性能制得苯乙烯增韧树脂（高抗冲聚苯乙烯HIPS和ABS）。苯乙烯增韧树脂传统的制备工艺需要耗费相当大的人力物力将溶液聚合得到的橡胶从惰性溶剂中析出、粉碎并且通过搅拌重新溶解在苯乙烯（St）中;为了简化工艺流程,节约成本,出现了本体原位制备法,即在苯乙烯中选择性的聚合丁二烯（Bd）直接制备苯乙烯的橡胶溶液,然后在自由基引发剂和单体（苯乙烯、丙烯腈）存在下进行自由基共聚合制备增韧树脂。本论文采用酸性膦酸酯钕盐(Nd(P₅₀₇)₃)、氢化二异丁基铝（Al（i-Bu）₂H）和倍半乙基铝（Et₃Al₂Cl₃）组成的催化剂体系,研究了Bd在St溶剂中的选择性聚合。并考察了溶剂种类,催化剂组成和聚合温度对Bd聚合规律及产物结构的影响。同时考察了催化剂的陈化方法、助催化剂的种类对聚合物分子量以及分子量分布的影响。结果表明:该催化剂可在苯乙烯中实现丁二烯的选择性聚合,在Al/Nd（摩尔比）为10,Cl/Nd（摩尔比）为2.0,聚合温度为50℃时,Bd的转化率可达90%以上,St转化率在1%以下。聚合物中苯乙烯含量在3%以下,丁二烯链节的顺-1,4-结构摩尔含量在90%左右,1,2-结构摩尔含量为2%左右。而且采用单体存在下陈化的方式,可获得分子量分布较窄的聚合物（M_w/M_n在3左右）。另外,采用该催化体系,通过调节Al/Nd（摩尔比）和陈化方式制备了具有不同分子量和分子量分布的橡胶胶液,并直接进行自由基接枝共聚合,制备了苯乙烯增韧树脂（HIPS和ABS）。并探讨了胶液性质（分子量及分子量分布）、胶含量、以及引发剂用量和种类对树脂的微观结构,聚合动力学,以及力学性能的影响。结果表明,随着胶含量的增加,HIPS和ABS的冲击强度都逐渐增大,而拉伸强度逐渐降低,同时断裂伸长率增大;与窄分子量分布的橡胶相比,宽分子量分布的橡胶增韧所得苯乙烯树脂冲击强度较高;随着引发剂用量的增加,接枝率略有上升;3,6,9-三甲基-3,6,9-三乙基-1,4,7-三过氧烷（TETMTPA）引发聚合所得HIPS的冲击强度较高,为147.7 J/m。1,1-二（叔丁基过氧基）环己烷（DP275B）引发聚合所得ABS形成了由内部具有规整网状结构的椭圆形的大粒径（＞2μm）颗粒组成的海岛结构,其冲击强度高达335.9 J/m。更多还原

【Abstract】 Polystyrene（PSt） is widely used in many engineering fields due to its excellent mechanical property and good processability.PSt is often modified with rubber particles, leading to high-impact polystyrene（HIPS）,acrylonitrile-butadiene-styrene（ABS）.However, in the traditional process of high impact materials,the rubber materials need to be isolated from the polymer solution and renewedly dissolved in St.Thus,much labor and expensive apparatus are required for evenly dissolving the rubber material in the monomer.A considerable reduction of variable costs can be achieved by adopting the so-called in-situ bulk polymerization process in which a solution of butadiene preplolymer is produced through selective polymerization of butadiene（Bd） in styrene（St） and then the resultant prepolymer solution was further subjected to a copolymerization of St and acrylonitrile（AN） initiated by radical initiator to produce high impact materials directly.In this study,the solution polymerization of 1,3-butadiene（Bd） was investigated in styrene（St） with the catalyst system comprised of Nd(P₅₀₇)₃（Nd）,Al（i-Bu）₂H（Al） and Et₃Al₂Cl₃（C1）.The effects of solvent,catalyst components and polymerization temperature on polymerization of Bd were examined.Meanwhile,the effects of aging methods and the kinds of cocatalyst on the molecular weight（M_W） and molecular weight distribution（M_W/M_n） of prepolymer were investigated.The results indicated that the selective polymerization of Bd was achieved in St by the above catalyst.The polymer yield was up to 90%at 50℃,Al/Nd molar ratio of 10 and CI/Nd molar ratio of 2.The produced polymer had extremely low content of St content（＜3%）,high cis-1,4 content of 90%and 1,2 content of 2%.Relative narrow M_W/M_n of polymer can be obtained when the catalyst was aged in the presence of Bd. Butadiene prepolymers with different M_w and M_w/M_n were synthesized using different Al/Nd molar ratios and aging methods.And then produced high impact materials directly （HIPS and ABS）.Furthermore,the effects of rubber content,molecular weight（M_W） and molecular weight distribution（M_W/M_n） of prepolymer,the amounts and kinds of initiators on the microstructure,kinetics of polymerization and the proprieties of final products were investigated.It is shown that as the rubber content increase,both impact strength of HIPS and ABS increased,the tensile strength decreased gradually and the elongation at break increased. The impact strength of resin toughed by prepolymer with broad M_W/M_n was higher than that of roughed by prepolymer with narrow M_W/M_n.As the amounts of initiator increased,both GD and RPVF slightly increased.The impact strength of HIPS obtained with TETMTPA as initiator was 147.7 J/m.Due to a more effective craze formation induced by fine particles with regular stereo network,the ABS obtained with DP275B displayed high impact strength, whose value reached 333.5 J·m^-1.更多还原