用多官能链转移剂通过普通自由基聚合制备两亲性杂臂星形聚合物  

SYNTHESIS OF AMPHIPHILIC HETEROARM STAR-SHAPED POLYMER BY THE USE OF POLYFUNCTIONAL CHAIN-TRANSFER AGENT via CONVENTIONAL FREE RADICAL POLYMERIZATION

作　　者：孔壮志[1] 罗志华[2] 付志峰[1] 石艳[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029 [2]北京地质大学工程技术学院,北京100083

出　　处：《高分子学报》2008年第2期102-106,共5页Acta Polymerica Sinica

摘　　要：以偶氮二异丁腈为引发剂,四(3-巯基丙酸季戊四醇四酯)(PETMP)为链转移剂进行甲基丙烯酸甲酯(MMA)的自由基聚合,得到了含有残余巯基的聚甲基丙烯酸甲酯大分子链转移剂(HS-PMMA).然后,以HS-PMMA作为大分子链转移剂进行甲基丙烯酸叔丁酯(tBMA)的自由基聚合,合成了杂臂星形聚合物.最后,将所得杂臂星形聚合物的PtBMA链段水解得到了两亲性杂臂星形聚合物.Amphiphilic heteroarm star-shaped polymer was synthesized by the use of polyfunctional chain transferagent via sequential free radical polymerization in three steps. Firstly, conventional free radical polymerization of methyl methacrylate （MMA） initiated by 2,2′-azobis（isobutyronitrile） （AIBN） was carried out at 70℃ in toluene in the presence of polyfunctional chain transfer agent, pentaerythritol-tetrakis （3-mercaptopropinate） （ PETMP）, with [MMA]o ： [PETMP]o ：[ AIBN]o to be 262.5：4：1 and [MMA]o = 5 mol/L. After polymerized for 2 h, the monomerconversion reached 43.61% ,and HS-PMMA with number-average molecular weight to be 4000 determined by gel permeation chromatography （GPC） and polydispersity index 1.37 was obtained. The ^1H-NMR spectrum of HS- PMMA confirmed that there were two unreacted thiol groups still existed at the center of PMMA chain. Secondly, the HS-PMMA obtained above was used as macro-chain-transfer agent for free radical polymerization of tert-butylmethacrylate （tBMA）. The polymerization of tBMA was carried out at 72℃ in toluene with [ tBMA]o： [HS- PMMA]o：[AIBN]o to be 655：5：1 and [tBMA]o = 1.57 mol/L. With the increase of tBMA conversion, the number-average molecular weights of the crude products shifted to higher molecular weight direction. Furthermore, their molecular weight distribution curves were unimodal through out the polymerization process. When t BMAconversion reached 70.00%, its number-average molecular weight increased from 4000 of HS-PMMA to 10600. Its ^1H-NMR spectrum showed that the residual thiol groups of the obtained heteroarm polymer decreased from 2.0 of the HS-PMMA to 0.4. That is to say, on average, the heteroarm polymer had two PMMA arms and 1.6 P t BMA arms. Finally,cleavage of the tea-butyl ester groups was achieved by treating the heteroarm star-shaDed polvmers indichloromethane with trifluoroacetic acid at room temperature for 6 days. The ^1H-NMR spectrum of hydrolyzed product showed that the ten-butyl protons of the

关 键 词：两亲性杂臂星形聚合物 自由基聚合 多官能链转移剂 自组装 

分 类 号：TQ316.322[化学工程—高聚物工业]