微波辐照下丙烯酰胺的原子转移自由基共聚合

Atom Transfer Radical Copolymerization of Acrylamide Under Microwave Irradiation

在微波辐射下,以水为反应介质,2-氯丙酰胺为引发剂,氯化亚铜/2,2'-联吡啶为催化体系,自制的磺基甜菜碱两性离子功能单体3-(2-甲基丙烯酰氧乙基二甲胺基)丙磺酸盐(DMAPS)与丙烯酰胺(AM)单体进行原子转移自由基共聚合反应,得到磺基甜菜碱型两性离子聚合物P(AM-DMAPS)。讨论了微波功率、反应时间、单体用量、引发剂用量、催化剂和配体用量等因素对聚合反应的影响,并与相应的热聚合法进行了对照。结果表明,微波辐射功率240 W,反应时间为1250 s时,微波辐射下共聚合的表观速率常数(Kappp)为热聚合法4.5倍,此时AM与DMAPS在水介质中的最佳合成条件为:单体总浓度4 mol/L(其中功能性单体DMAPS在混合单体中所占摩尔分数为1.0%),引发剂浓度0.015 mol/L,催化剂浓度0.01 mol/L。此时转化率为40.15%,Mn为46410。

Zwitterionic copolymers（P（AM DMAPS）） were successfully synthesized in aqueous solution via the atom-transfer radical polymerization（ATRP） between acrylamide（AM） and a homemade zwitterionic monomer of 3-dimethyl（methacryloyloxyethyl） ammonium propane sulfonate（DMAPS） under microwave irradiation（MI） using 2-chloropropionamide as initiator and CuCl/2,2′-bipyridine as catalyst.The effects of microwave power,reaction time and the amount of initiator,catalyst and ligand on the polymerization were studied and compared with those of conventional heating method.Our results showed that the apparent rate constant（Kappp） of copolymerization under microwave radiation with radiation power of 240 W for 1250 s was 4.5 times that of traditional thermal polymerization.The conversion was 40.15% and Mn was 46410.The optimized conditions for copolymerization are as follows：the total monomer concentration is 4.0 mol/L in which the molar fraction of functional monomer DMAPS is 1%,the initiator concentration is 0.015 mol/L,and the catalyst concentration is 0.01 mol/L.