紫外光固化超支化聚硅氧烷的合成及其光固化动力学研究

利用γ-甲基丙烯酰氧基丙基三甲基硅氧烷的受控水解反应即A2-B3单体对法来制备超支化聚硅氧烷,并对合成出的聚合物通过FT-IR、1H-NMR和多角度激光光散射技术(MALLS)进行了表征.结果表明,所得聚合物具有超支化结构且分子中含有大量活性官能团,从而可以实现紫外光引发固化.通过等温差示光量热实验(DPC)研究了聚合物结构、引发剂用量、光强度和聚合温度对聚合物光固化行为的影响规律,并得到了其中一种聚合物的光固化动力学参数,光固化反应总级数约为3,表观活化能为16.9kJ/mol.

SYNTHESES OF UV-CURABLE HYPERBRANCHED POLYSILOXANES AND STUDIES ON THEIR PHOTO-CURING BEHAVIOR

UV-curable hyperbranched polysiloxanes were synthesized via hydrolysis of γ-methacryloxyprop-yltrimethyloxysilane (A-174) by controlling the amount of water.Macromolecular structures of the polymers obtained were characterized and confirmed by FT-IR, ~1H-NMR spectra and multi-angle laser light scattering technology(MALLS).The results indicated that the hyperbranched polysiloxanes carrying a large amount of functional vinyl groups could be cured under UV-irradiation.Their photo-initiated curing kinetics were studied by isothermal differential photo calorimeter (DPC) test.It was found that both the polymerization rate and the ultimate conversion first increased and then decreased with the increase in the molecular weight of the polymer and the photoinitiator concentration.The increase in UV-light intensity can lead to increase of both the polymerization rate and the ultimate conversion,and particularly, the polymerization rate is proportional to the square root of light intensity.Although elevated temperature can indeed improve the polymerization rate and the ultimate conversion,the effect of temperature on polymerization rate is not prominent.The total exponent of the photo-polymerization of the polymer 3# is about 3,and the apparent activation energy is 16.9 kJ/mol,calculated from an autocatalytic model.