聚硅氧烷-(甲基)丙烯酸酯共聚乳液的制备与性能

Synthesis and Properties of Copolymer Emulsion of Polysiloxane and Polyacrylate

八甲基环四硅氧烷(D4)在复合乳化剂的作用下开环形成端羟基线型聚硅氧烷乳液,然后加入γ-甲基丙烯酰氧丙基三甲氧基硅(KH570),pH=4的条件下KH570水解,再与端羟基线型聚硅氧烷脱水形成含反应双键的长侧链聚硅氧烷,再加入(甲基)丙烯酸酯单体,自由基聚合得到聚硅氧烷-(甲基)丙烯酸酯乳液。通过这种方法,有机硅单体可占到整个单体质量的80%。然后,通过29SiNMR、FTIR对含反应双键的聚硅氧烷及聚硅氧烷-(甲基)丙烯酸酯聚合物进行结构表征,并对乳液及其聚合物膜的性能进行了表征,结果表明,KH570完全水解后与端羟基聚硅氧烷形成含反应双键的长侧链聚硅氧烷,同时也表明当有机硅质量占整个单体质量的80%时乳液涂膜吸水率最终为5.3%,表面自由能为6.56 mN/m,聚硅氧烷-(甲基)丙烯酸酯共聚物最大热失重速率温度为577℃。聚合物的耐水性和热稳定性能有很大提高。

The polysiloxane containing unsaturated double bond has been synthesized by using silane coupling agent （ KH570 ） which was hydrolyzed under pH = 4 and terminal-hydroxyl polydimethylsiloxane which was prepared from octamethylcyclotetrasiloxane. And then, polyacrylate emulsion modified by long chain branched polysiloxane containing unsaturated double bond was obtained from （meth） acrylate and unsaturated long chain branched polysiloxane by free radical polymerization reaction. In this way, the amount of silicone in the copolymer can reach 80%. The obtained polysiloxane containing unsaturated double bond and modified copolymer were characterized by means of FTIR,29SiNMR. And also the properties of the emulsion and emulsion film were tested. The results show that KH570 was fully hydrolyzed and then dehydrated with terminal-hydroxyl polydimethylsiloxane, which eventually made unsaturated long chain branched polysiloxane. It also shows that, when the mass fraction of silicone was 80% , the water absorption was eventually 5.3%, the surface free energy was 6. 56 raN/m, and the temperature of maximum thermal weight loss rate was 577 %. The hydrophobic property and thermal stability was significantly improved. This unsaturated long chain branched polysiloxane modified copolymer emulsion could be used as high hydrophobic and high heat-resistant functional polymeric material.