Novel thermosensitive polymers obtained from N-vinylacetamide derivatives

首先，合成了一系列具有不同烷基的n -乙烯基烷基酰胺，并考察了它们在聚合物中的溶解行为。在自由基引发剂的作用下，对n -乙烯基异丁胺（NVIBA）进行了自由基聚合反应。结果表明，NVIBA的聚合性与n -乙烯乙酰胺（NVA）相似。所制备的聚NVIBA在39℃时具有较低的临界溶解温度（LCST）。所得到的具有不同烷基的聚（n -乙烯基烷基酰胺）的水溶性根据分子的形状以及烷基的侧链长度而变化。在10 ~ 90‰之间，共聚物在水中表现出明显的lcst，这取决于共聚单体种类和含量的变化。然后，采用自由基共聚法制备了由聚苯乙烯芯和表面聚（NVIBA）支组成的热敏单分散颗粒。并对VNIBA制备的水凝胶及其应用前景进行了研究。水分子与这些合成聚合物之间的相互作用受到了广泛的关注。通过差示扫描量热仪（DSC）的测量，将这些聚合物的水合条件与聚n -烷基丙烯酰胺衍生物的水合条件进行了比较。结果表明，聚（NVIBA）等聚（n -乙烯基烷基酰胺）的LCSTs高于聚（n -异丙基丙烯酰胺）等聚（n -烷基丙烯酰胺）的LCSTs。讨论了热敏性聚合物的水化作用。

First, a series of N-vinylalkylamide with different alkyl groups was synthesized and their solution behavior in a polymeric from was examined. The free radical polymerization of N-vinylisobutyramide (NVIBA) was carried out in various solvents in the presence of a radical intiator. It was found that the polymerizability of NVIBA is similar to that of N-vinylacetamide (NVA). The resulting poly (NVIBA) showed a lower critical solution temperature (LCST) sharply at 39ﾟC.The water solubility of the resulting poly (N-vinylalkylamide) with different alkyl groups was found to vary, depending on the molecular shapes as well as the side chain length of alkyl groups. The copolymer in water showed LCSTs sharply between 10 and 90ﾟC,depending on changes in their comonomer species and its content. Then, thermosensitive monodisperse particles which consisted of polystirene core and poly (NVIBA) branches on their surface were prepared by free radical copolymerization. And slso, hydrogels prepared from VNIBA and their possible applications were also studied. The interactions between water molecules and these sythetic polymers have attached much attention. Also, the hydrated condition of these polymers were compared with that of poly (N-alkylacrylamide) derivatives by measurement of differential scanning calorimeter (DSC). As a result, aqueous poly (N-vinylalkylamide)s such as poly (NVIBA) was found to show higher LCSTs than that of aqueous poly (N-alkylacrylamide)s such as poly (N-isopropylacrylamide). We discussed the hydration of thermoseitive polymers.