窄分子量分布的聚[甲基(3,3,3-三氟丙基)硅氧烷]的合成与表征

Synthesis and Characterization of Poly[methyl(3,3,3-trifluoropropyl)siloxane] with Narrow Molecular Weight Distribution

聚[甲基(3,3,3-三氟丙基)硅氧烷](PMTFPS)具有非常优越的物理化学性能,是一种有着重要应用价值的有机硅材料。研究以正丁基锂与1,3,5-三甲基-1,3,5-三(3’,3’,3’-三氟丙基)环三硅氧烷(简称F3)反应所得硅醇锂为引发剂,在正己烷与THF的混合溶剂中,在较高的单体浓度下实现了F3的可控阴离子开环聚合,得到了窄分子量分布(1.03～1.08)的含氯苄端基的聚[甲基(3,3,3-三氟丙基)硅氧烷](PMTFPS-BzCl),聚合物得率在93%以上。结果显示,在F3的开环聚合过程中聚硅氧烷活性链的"反咬"与再分布副反应得到有效的抑制。

Poly methyl（3,3,3-trifluoropropyl）siloxane（PMTFPS） is an important silicone material with great value due to its superior physical and chemical properties.In this study,using the high-vacuum polymerization technique and the co-solvent of hexane and THF at 0℃,the controlled anionic ring-opening polymerization（ROP） of 1,3,5-trimethyl-1,3,5-tris（3’,3’3’-trifluoropropyl）cyclotrisiloxane（F3） was carried out,and then the benzyl chloride-terminal poly methyl（3,3,3-trifluoropropyl）siloxane（PMTFPS-BzCl） was synthesized.The initiator used for the ROP is the lithium silanolate which was made directly by the reaction of n-butyllithium and F3 in the reactor at room temperature before polymerization.The obtained polymers,PMTFPS-BzCl,has narrow molecular weight distribution with distribution rang of 1.03 to 1.08,and its yield is more than 93%.It indicates that,using the proposed synthesis process,the ＂back-biting＂ by the chain ends as well as the redistribution reactions between the siloxane chains were efficiently suppressed during the anionic ROP of F3.