阴离子聚合法合成PMMA-b-PMTFPS嵌段共聚物

以含缩醛官能团的有机锂为引发剂, 将甲基丙烯酸甲酯(MMA)与含氟硅氧烷单体1,3,5-三甲基-1,3,5-三(3',3',3'-三氟丙基)环三硅氧烷(F3)阴离子嵌段共聚, 获得了窄分子量分布的聚甲基丙烯酸甲酯-b-聚甲基(3,3,3-三氟丙基)硅氧烷](PMMA-b-PMTFPS)嵌段共聚物, 并用GPC, 1H NMR, FTIR和DSC对嵌段共聚物进行了表征. 研究结果表明, 在THF中利用PMMA-OLi对F3进行阴离子开环聚合时, 单体F3浓度的选择对提高嵌段共聚物产率至关重要.

Synthesis of Poly ( methyl methacrylate ) -block-Poly [ methyl ( 3,3,3-trifluoropropyl) siloxane ] Diblock Copolymers via Anionic Polymerization Method

The anionic block copolymerization of methyl methacrylate(MMA) and 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)cyclotrisiloxane (F3) was carried out with an acetal-functionalized alkyllithium as the initiator, and poly(methyl methacrylate)-b-polymethyl(3,3,3-trifluoropropyl)siloxane](PMMA-b-PMTFPS) diblock copolymers with a narrow molecular weight distribution were synthesized. The block copolymers were characterized by gel permeation chromatography(GPC), proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy(FTIR) and differential scanning calorimetry(DSC). The results show that the selection of the concentration of F3 was very important for obtaining PMMA-b-PMTFPS diblock copolymers with high yield when the terminal lithium alkoxide functional poly(methyl methacrylate)(PMMA-OLi) was served as the macroinitiator of anionic ring-opening polymerization(ROP) of F3. Additionally, DSC results show that the glass transition behaviors of PMMA-b-PMTFPS diblock copolymers were dependent on the content of PMTFPS blocks. The glass transition temperature of PMTFPS blocks is about -69—-70 ℃, and the glass transition temperature of PMMA blocks is about 128—130 ℃.