抄録
Copolymerization of N-isopropylacrylamide (NIPAM) with styrene (2 mol% in feed) was performed using AIBN as an initiator to give a linear copolymer (la) of low-molecular-weight (Mn = 9.0 x 103, Mw/Mn = 1.49). The content of styrene in la was estimated as 1.8 mol% from 1H NMR spectra. Cross-linked poly(N-isopropylacrylamide) (2) was prepared using divinylbenzene (DVB, 2 mol% in feed) as a cross-linker (Mn = 8.6 x 103, Mw/Mn = 1.74). Lower critical solution temperature (LCST) of la and 2 determined from the transmittance of their 0.35% aqueous solution were 28.9 and 27.0 °C, respectively. When 1.0% aqueous solution of la was heated over LCST, the solution turned cloudy without agglomeration. In contrast, 2 gave agglomerates with heating over LCST. The effect of hydrophobic interaction, cross-linking agent, and cross-linking degree on the agglomeration tendency of 2 was discussed.
