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，并研究了它们在聚合物中的溶液行为。在自由基引发剂存在下，N-乙烯基异丁酰胺（NVIBA）在不同溶剂中进行自由基聚合。发现NVIBA的聚合性与N-乙烯基乙酰胺（NVA）相似。得到的聚（NVIBA）在39 ℃下显示出较低的临界溶解温度（LCST）。发现具有不同烷基的所得聚（N-乙烯基烷基酰胺）的水溶性不同，这取决于分子形状以及烷基的侧链长度。水中的共聚物在10和90 ℃之间急剧显示LCST，这取决于它们的共聚单体种类及其含量的变化。然后，通过自由基共聚法制备了以聚苯乙烯为核，表面为聚（NVIBA）支链的单分散温敏粒子。并对VNIBA水凝胶的制备及其应用进行了研究。水分子与这些合成高分子之间的相互作用一直受到人们的关注。同时，通过差示扫描量热仪（DSC）的测量，比较了这些聚合物与聚（N-烷基丙烯酰胺）衍生物的水合情况。结果，发现含水聚（N-乙烯基烷基酰胺）如聚（NVIBA）显示出比含水聚（N-烷基丙烯酰胺）如聚（N-异丙基丙烯酰胺）更高的LCST。讨论了热敏性高分子的水化反应。

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.