Preparation Of Hyperbranched Poly(Siloxy)Silanes And Study On Their UV Curing Kinetics

For their unique molecular structure and performance, hyperbranched polymers and dendrimers were regarded as having low viscosity, better rheology and dissolvability. Compared with dendrimers, hyperbranched polymers were superior in synthesis strategy, which can be obtained in one-pot polymerization process, and the properties of products were basically similar to that of dendrimers. Organic siloxane consists of repeating flexible Si-0 bond, which results in both heating and cryogenic resistance in company with excellent thermal and chemical stability. The peripheral reactive groups in outside of polymers made it easy to construct highly branched polymers, and act as a "matrix" if further functionalization was needed on polymers. This thesis was mainly involved in research of synthetic strategy of hyperbranched polysiloxysilanes, where both hydrolytic way and anhydrous methods were employed to prepare hyperbranched polysiloxysilanes, and a comparison study was aoso carried out between them. The prepared hyperbranched polysiloxysilane was further functionalized, and its UV-curing behavior was studied. The following three parts were mainly involved.(1) Two functional chlorosilanes, chloromethylethylvinylhydrosilane and chlorodimethylallylsilane were prepared via Grignardreagents. AB₂-type monomers, methylbis(methylethylvinylsiloxy)silane(SiMV), and methylbis(dimethylallylsiloxy)-silane(SiMB) were synthesized via the hydrolyzation of chlorosilane and dichlorosilane catalyzed by (dimethylamino)pyridine (4,4'-DMAP) and triethylamine. Free radical initiated UV-curable hyperbranched poly(siloxysilane)s HPSiMV and HPSiMB carrying double bond (-CH=CH₂) and allyl group were obtained by polyhydrosilation reaction of SiMV and SiMB. The structure of AB2-type monomers and hyperbranched poly(siloxysilane)s were characterized by FTIR, ¹H-NMR, ²⁹Si-NMR,SEC-MALLS and elemental analysis. The result indicated that cycloaddition reaction existed in the one-step polymerization. The purification of hyperbranched can be fulfilled by extraction. The conversion of double bond, which was affected by different atmospheres and accelerants, was studied via FTIR. The results indicated that different atmospheres can cause little change to the conversion of HPSiMV, in contrast, marked acceleration in HPSiMB with allyl terminal groups was observed when it was catalyzed by...