本研究可分為兩個部分,第一部分是以利用自由基聚合法聚合出兩種不同分子量的線性聚異丙基丙烯醯胺高分子(簡稱PNIPA)並與Aldrich(Mw 4.6×105)做比較。分子量測量使用膠體滲透層析法,分別得到分子量為3.6×105、3×105。並藉由熱示差掃描熱分析儀量測不同重量百分比濃度水溶液的相變化溫度。結果證實,分子量的大小與相變化溫度有關。於同一個濃度下,高分子量有較高的相變化溫度。這是因為較高的分子量,分子鏈間容易產生糾纏,而提高相變化溫度。 第二部分是加入具有陰離子單體的苯乙烯磺酸鈉(簡稱SSAS),並以自由基聚合法聚合得到poly(NIPA-SSAS)共聚高分子(簡稱PNS)。同樣配置不同濃度的水溶液,再利用透光度儀來得知相變化溫度。由於離子性單體的引進,減少了NIPA與水分子間的氫鍵鍵結,使得相變化溫度降低。此外,再引進疏水性的苯乙烯(styrene)單體,並進行三單體的共聚合反應,形成poly(NIPA-SSAS-Styrene)共聚高分子(簡稱PNST)。並與PNS的相變化溫度做比較。
This study consists of two different topics. First, in order to compare with Aldrich’s standard poly(N-isopropylacrylamide) (Mw4.6×105), we obtained two linear poly(N-isopropylacrylamide) (PNIPA) with different molecular weights by free radical polymerization, 3×105、3.6×105 respectively. Compounds’ molecular weights (Mw) are determined by gel permeation chromatograph, we also used differential scanning calorimetry to determine the phase transition temperature of different concentration in aqueous solution. This result reveal that the phase transition temperature for PNIPA solution depends on polymers’ molecular weight. For certain concentration, high molecular weight polymer has the highest phase transition temperature and prone to entangle between chains. Second, introducing 4-styrene sulfonate acid sodium as an anion monomer (SSAS) to synthesize poly(NIPA-SSAS) copolymer (PNS) by free radical polymerization. We used light transmittance instrument to determine the phase transition temperature. We also observed that the phase transition temperature can be decreased by adding anion monomers to reduce the interaction between NIPA and water molecules. Moreover, we also introduced styrene monomers to precede tri-monomer copolymerization reaction to obtain poly(NIPS-SSAS-Styrene) (PNST) and compare with the phase transition temperature between PNST and PNS.