摘要
采用紫外光引发光聚合得到了聚甲基丙烯酸N ,N 二甲氨基乙酯〔P(DMAEMA)〕均聚物和不同组成的聚甲基丙烯酸N ,N 二甲氨基乙酯 /丙烯酸 2 乙基己酯〔P(DMAEMA/EHA)〕共聚物。傅立叶红外光谱和核磁共振氢谱测定了P(DMAEMA/EHA)共聚物的链结构 ,结果表明 :聚合的投料比与所得产物的实际组成比一致。在 pH >8,P(DMAEMA/EHA)共聚物溶液的低临界溶液温度 (LCST)随聚合物中EHA组分的增加逐渐下降 ;在pH≤ 8时 ,则观测不到体系的LCST。 37℃下均聚物及共聚物试样 (D、D/E1、D/E2、D/E3)的pH敏感点分别为8 80 ,8 72 ,8 37,8 2 9。共聚物结构中EHA组分越多 ,则 pH敏感点越低。P(DMAEMA)均聚和共聚物的LCST随着NaCl浓度的升高而线性下降 ,且下降的速率相等。
Poly(N,N-dimethylaminoethyl methacrylate) 〔P(DMAEMA)〕 and poly(N,N-dimethylaminoethyl methacrylate/2-ethylhexyl acrylate)〔 P(DMAEMA/EHA)〕 copolymers were synthesized by photopolymerization using benzoin ethylether as initiator.The chain structures were obtained,and their compositions in copolymers were characterized by using infrared spectroscopy and 1H-NMR.The study focused on thermal and pH sensitive behaviors of chain structure under different external conditions.At pH>8,the lower critical solution temperatures(LCST) of P(DMAEMA) and P(DMAEMA/EHA) in aqueous solution decreased with increasing EHA contents,but at pH≤8,LCST could not be observed.At 37 ℃,the sensitive pH values of P(DMAEMA) and P(DMAEMA/EHA) (D?D/E1?D/E2?D/E3) were 8.80,8.72,8.37,8.29 respectively.Sensitive pH values of the copolymers decreased with increasing EHA contents.The results also showed that LCST of P(DMAEMA) and P(DMAEMA/EHA) in aqueous NaCl solution decreased linearly at the same ratio when NaCl concentration was increased.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2003年第2期65-68,共4页
Fine Chemicals
