Study On Hydrosilylation Of Acrylate Modified By Silicone

Acrylate modified by silicone is a kind of organofunctional silicone, which has broad prospects in polymer modification, UV-curable coatings, anti-fouling paint and contact lenses. Hydrosilylation appears widely in synthesizing organofunctionally terminated telechelic silicone under mild condition. So it is a effective method to prepare acrylate modified by silicone using hydridosilyl group terminated silicone with vinyl or allyl terminated acrylate. In this paper, hydrosilylation of acrylate modified by silicone was discussed, the main research work and conclusions were summarized as the following:(1) Phenyl siloxane-containing acrylate monomer was prepared through hydrosilylation of allyl methacrylate with 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane. The characterization were performed by the preliminary analysis of monomer’s structure, end-groups and included the determination of molecular weight, molecular weight distribution using fourier transform infrared spectrometry, nuclear magnetic resonance, and gel permeation chromatography. According to the characterization results of gel permeation chromatography, the structures of high, middle and low molecular weight were characterized by triple electrospray ionization time of flight mass spectrometry, triple ultra performance liquid chromatography-time of flight mass spectrometry, gas chromatography-mass spectrometry separately. And the results showed that the silicone was terminated by methacryloxypropyl group, methacryloyloxy and propyl groups, including seperately dimer, addition product and disproportionate component. Among the monomer, the molecular weight of dimer, addition product and disproportionate component was 998,577 and 329 respectively.During the process of synthesis, the optimum feeding way, reaction temperature, addition ratio were selected by experiment. In conclusion, The optimum condition of feeding way was summarized as the following:mixing up allyl methacrylate, inhibitor, catalyst with heating and stirring for some time, and then slowly adding 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane to react. The optimum reaction temperature was 50～70℃. The optimum addition ratio was 1:2 for Si-H group and CH2=CHCH2-group. According to the optimal synthetic method, with chloroplatinic acid/tetrahydrofuran solution as the catalyst,2,6-di-tert-butyl-4-methylphenol as inhibitor and 3 h reacting time, the hydridosilyl group of silicone was reacted fully, besides, the product was colourless transparent liquid. According to the characterization results of 1H-NMR, the ratio of end-groups that include methacryloxypropyl group, methacryloyloxy group, propyl group was 100:12:5. Furthermore, the content of dimer, addition product, disproportionate component was 12.6%,84.3%,3.1% separately, which was determined by GPC.(2) Based on the direction of phenyl siloxane-containing acrylate monomer’s conclusion, polydimethylsiloxane terminated by methacryloxypropyl group was prepared through hydrosilylation of allyl methacrylate with polydimethylsiloxane terminated by hydridosilyl group. The characterization was performed by structure analysis using fourier transform infrared spectrometry, nuclear magnetic resonance, and triple electrospray ionization time of flight mass spectrometry. The hydridosilyl group of polydimethylsiloxane was reacted fully. And the results showed that the product contained not only polydimethylsiloxane terminated by methacryloxypropyl group, but also a small amount of polydimethylsiloxane terminated by methacryloyloxy and propyl groups. From the preliminary study, it was found that the conclusion of phenyl siloxane-containing acrylate monomer was also generally applicable to polydimethylsiloxane terminated by methacryloxypropyl group.The originality in this thesis:(1) Taking phenyl siloxane-containing acrylate monomer as a subject, a variety of characterization methods were used to analyze the components, determining the type of principal component and by-product. It has solved the problem of difficult analysis of acrylate modified by silicone and established the analysis method.(2) During the optimizing experimental study on phenyl siloxane-containing acrylate monomer and polydimethylsiloxane terminated by methacryloxypropyl group, the optimum reaction conditions were concluded, which has established foundation for industrialization.