P26 超音波を用いたポリ(N-イソプロピルアクリルアミド-co-メタクリル酸2-ヒドロキシエチル)の合成(ポスターセッション)

概要

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Poly (N-Isopropylacrylamide-co-2-hydroxyethyl methacrylate) (P(NIPAAm-co-HEMA)) was synthesized using ultrasonic irradiation without chemical initiator in the mixed solvent of water and ethanol. Effects of solvent composition, monomer molar ratio, and reaction temperature on time course of conversion to polymer, number average molecular weight, and polydispersity were investigated in order to synthesize the polymer with low molecular weight distribution (i.e., low polydispersity). Lower ethanol composition of solvent resulted in higher conversion to polymer, faster decrease of molecular weight, and lower polydispersity. Ethanol acts as a scavenger for radical polymerization, so that higher ethanol composition decreases the polymerization rate. Faster polymerization rate gives faster generation of polymer, and faster degradation of generated polymer, which resulted in faster decrease of molecular weight and lower polydispersity. Higher NIPAAm ratio resulted in higher polymerization rate, faster polymer degradation rate, and lower polydispersity. In the case of the homopolymer of PNIPAAm and PHEMA, PNIPAAm radical has lower reaction activity with ethanol than PHEMA radical, so that PNIPAAm polymerizes faster than PHEMA. Reaction temperature slightly affected the reaction rate. Temperature dependence of polymerization is positive but that of radical formation is negative, and the effect of those two factors might be almost same.
2013-10-25