侧链为聚乙二醇单甲醚的高接枝率水溶性梳状接枝共聚物的合成与表征

Synthesis and Characterization of Water-Soluble Comb-Shaped Graft Copolymer with Side Branch Poly(Ethylene Glycol) Methyl Ether

通过自由基引发溶液聚合,将聚乙二醇单甲醚(mPEG)丙烯酸单酯大单体与丙烯酸(AA)小单体共聚,合成一系列侧链为mPEG、不同侧链长度且具有较高接枝率的水溶性梳状接枝共聚物聚丙烯酸接枝聚乙二醇单甲醚(PAA-g-mPEG),并对共聚物进行表征。实验结果表明,mPEG丙烯酸单酯大单体和AA小单体的共聚活性较高;梳状接枝共聚物PAA-g-mPEG的接枝率较高,即使侧链为链段较长的重均相对分子质量为5 000的mPEG(mPEG5 000),共聚物中mPEG5 000的质量分数仍可高达55.7%。热重分析结果表明,梳状接枝共聚物在100℃下具有较好的热稳定性。

A series of water- soluble comb- shaped graft copolymers ,poly （acrylic acid） -g- poly （ethylene glycol） methyl ether （ PAA - g - mPEG ）, with side chain poly （ ethylene glycol ） methyl ether （ mPEG ） were synthesized by free -radical copolymerization of acrylic acid（AA） and mPEG acrylic monoester macromonomers in iso - propanol solution. The copolymer had high graft ratio and side chain length was different, mPEG acrylic monoester macromonomer was synthesized by acrylation of monomethoxy poly （ ethylene glycol） with acryloyl chloride, mPEG acrylic monoester macromonomer and AA successfully copolymerized actively. Graft ratio of comb- shaped graft copolymer PAA - g - mPEG was high. Even if mPEG with weight average relative molecular mass 5 000 （mPEG5 000 ） was used as side chain, mass fraction of mPEG5000 in copolymer could reach 55.7%. The comb - shaped graft copolymer was stable at 100 ℃.