摘要
利用大分子单体技术通过自由基共聚法合成了由甲基丙烯酸(MAA)和N,N-二乙基丙烯酰胺(DEAM)组成的几种不同组成的P(MAA-g-DEAM)接枝共聚物.通过UV-Vis透光率的测定和荧光探针技术,对共聚物水溶液的相行为进行了研究.研究表明,此接枝共聚物具有相互独立的温度和pH敏感性;几种组成不同的P(MAA-g-DEAM)接枝共聚物具有基本相同的低临界溶解温度(LCST);它们的临界相变pH与接枝共聚物的组成有关,温敏性PDEAM枝链的接枝率越高,其临界相变pH越高.pH>5.5时,接枝共聚物的主链是一种较为松散的线团构象;pH<5.5时,接枝共聚物的主链是一种较为压缩的线团构象.这种接枝共聚物高分子聚集体在新的纳米复合材料的合成方面有可能获得应用.
Several temperature- and pH-sensitive poly（methacrylic acid-g-N, N-diethylacrylamide） （P（MAA-g-DEAM）） graft copolymers with different compositions were synthesized by free-radical copolymerization utilizing macromonomer technique. The phase behaviors of P（MAA-g-DEAM） in dilute aqueous solutions were investigated by UV-Vis transmittance measurements and fluorescence probe technique. Studies demonstrated that the P（MAA-g-DEAM） copolymers had temperature- and pH-sensitivities, the two sensitivities were independent each other. These graft copolymers with different compositions had the approximately identical lower critical solution temperature （LCST）, their critical phase transition pH values were dependent on the composition of graft copolymers and increased with increasing mass fraction of PDEAM. The PMAA main chain of P（MAA-g-DEAM） in dilute aqueous solution is an expanded coil conformation when the solution pH is higher than 5.5, and the PMAA main chain of P（MAA-g-DEAM） in dilute aqueous solution is a hyper-coiled conformation when the solution pH is less than 5.5. The unique properties of the graft copolymers may find some uses in the design and synthesis of novel nanocomposite materials.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2006年第5期579-583,共5页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20373039)资助项目
关键词
温度和pH敏感性
接枝共聚物
相行为
临界相变pH
低临界溶解温度
Temperature- and pH- sensitivity, Graft copolymer, Phase behavior, Critical phase-transition pH, Lower critical solution temperature
