两端疏水聚丙烯酰胺的合成及疏水缔合性能

Synthesis of Hydrophobically Both End-capped Polyacrylamide and Associative Property

刘朋飞 范雅珺 梁兵

LIU Pengfei，FAN Yajun，LIANG Bing

为获得疏水缔合作用较好的两端疏水聚合物及其性能特征，以丙烯酰胺（AM）为单体，2，2'-偶氮二异丁基十二脒盐酸盐（AIBL）为引发剂，双（硫代苯甲酰基）二硫化物（BTBDS）为链转移试剂，在二甲基亚砜（DMSO）中进行可逆加成-断裂链转移自由基聚合（RAFT），制得端基疏水聚丙烯酰胺；再进行过氧化双月桂酰（LPO）和AIBL的联合自由基诱导处理，获得两端疏水聚丙烯酰胺。采用核磁、凝胶渗透色谱、紫外、荧光芘探针和表面张力测试对AM的转化率、聚合物的分子量及其分布，以及疏水缔合作用进行了研究。结果表明，通过调整引发剂AIBL的加量和反应时间可以控制单体AM的转化率和聚合速率。当采用体积分数35%的乙腈与水共混溶剂作淋洗液时，可以较为准确地测定聚合物的分子量及其分布。一定转化率下，用RAFT法合成聚丙烯酰胺时，单体转化率和聚合反应速率均随反应时间的增加而线性增加，聚合物的分子质量分布系数约为2.0，表明该制备方法具有一定程度的可控性；与端基疏水聚丙烯酰胺相比，两端疏水聚丙烯酰胺的分子质量略有增加，分子量分布变化较小，分子内缔合强，临界缔合浓度（cCAC=2 g/L）有所增加，聚合物浓度大于cCAC后的疏水缔合作用强。图11参28

In order to obtain hydrophobically both end-capped polyacrylamide with good hydrophobic association，the precursor of hydrophobically end-capped polyacrylamide was obtained through reversible addition-fragmentation chain transfer （RAFT）polymerization of acrylamide （AM） in dimethyl sulfoxide （DMSO） by 2,2'-azobis （2-methylpropiondodecylamidine）dihydrochloride（AIBL）as initiator agent，the dithioester as chain transfer agent by bis（thiobenzoyl）disulfide（BTBDS）reacting with AIBL in situ . Then the precursor reacted with a combination of lauroyl peroxide（LPO）and AIBL to prepare hydrophobically both end-capped polyacrylamide by radical-addition-fragmentation-coupling process. The structure of hydrophobically both end-capped polyacrylamide was confirmed by 1H-NMR spectra and UV spectra. The conversion rate of acrylamide was calculated from 1H-NMR spectra. The molecular weight and molecular weight distribution were determined by gel permeation chromatography （GPC）. The properties of hydrophobically modified polyacrylamide were studied with fluorescence probe and surface tension meter. The results showed that the conversion rate and polymerization rate of AM could be controlled by adjusting AIBL content and polymerization time. Telechelic hydrophobically modified polyacrylamide could be analyzed more accurately by GPC with mixtures containing 35% of acetonitrile as eluent. When polyacrylamide was polymerized by RAFT under a certain conversion，the conversion rate and polymerization rate of AM increased linearly along with polymerization time and the polydispersity index （PDI） of polyacrylamide was about 2.0，showing a certain degree of controllability of the preparation method. Compared with hydrophobically end-capped polyacrylamide，the molecular weight of hydrophobically both end-capped polyacrylamide increased slightly， molecular weight distribution had little change， intramolecular association strengthened， the critical aggregation concentration（cCAC=2 g/L）increased，and hydrophobic association improved when the concentration of polymer was bigger than cCAC.

10.19346./j.cnki.1000-4092.2017.04.020