负离子法合成POSS端基官能化聚丁二烯及其表征

Synthesis and Characterization of Polyhedral Oligomeric Silsesquioxane End Functionalized Polybutadiene by Anionic Polymerization

以丁二烯(Bd)为单体,一氯丙基七异丁基多面体低聚倍半硅氧烷(POSS-Cl)为封端剂,正丁基锂(n-BuLi)为引发剂,环己烷为溶剂,采用负离子聚合技术合成了POSS端基官能化聚丁二烯(PB-POSS)。采用核磁共振(~1H-NMR、^(13)C-NMR)和凝胶渗透色谱(GPC)对PB-POSS的结构和相对分子质量、相对分子质量分布进行了表征。NMR表明POSS与聚丁二烯锂(PBLi)发生封端反应生成了PB-POSS;GPC表明POSS封端PB过程中易发生副反应,生成二聚体副产物。为此,系统考察了结构调节剂种类和用量、添加剂LiCl、低温条件及在封端前加入1,1-二苯基乙烯(DPE)或苯乙烯(St)等方法对POSS封端PB反应的影响。结果表明,采用封端前加入DPE或St可以消除副反应,避免生成二聚体;此外还对封端反应机理进行了探讨。

Heptaisobutyl polyhedral oligomeric silsesquioxane functionalized polybutadiene（ PB-POSS） was synthesized using butadiene as monomer,chloropropylheptaisobutylpolyhedral oligomeric silsesquioxane（ Cl-POSS） as terminator,n-BuLi as initiator,cyclohexane as solvent via anionic living polymerization technique. The structure and molecular weight,molecular weight distribution of PB-POSS were characterized by 1 H-NMR and 13 C-NMR and gel permeation chromatography（ GPC）. The 1 H-NMR and 13 C-NMR results clearly prove that the reaction of polybutadienyllithium with Cl-POSS is carried out and PB-POSS is successful synthesized. The GPC curves show that POSS incorporation into the end of PB causes side effects and dimeric side-products are observed by GPC. Then the effects of the species and content of structure modifier,additive LiCl,low reactive temperature and end-capping of the chain end with 1,1-diphenylethylene（ DPE） and styrene（ St） on functionalization reaction were investigated to overcome side reaction. The results show that only by adding DPE or St before functionalization reaction could prevent the production of dimeric side-products.The functionalization reaction mechanism was also discussed.