Characterization and water vapor sorption property of ABA-type triblock copolymers derived from polyimide and poly(methyl methacrylate)

The characterization of ABA-type triblock copolymer films derived from polyimide (PI) macroinitiator and poly(methyl methacrylate) (PMMA) synthesized by atom transfer radical polymerization was investigated by focusing on different block lengths of PMMA. The hydrophobic property tends to increase with increasing PMMA content in the triblock copolymers, while the PMMA blocks enhance the charge transfer interaction between the PI segments. The water vapor sorption measurement of triblock copolymers was determined at 35 degrees C. The water vapor solubility of triblock copolymers tends to decrease with increasing PMMA content. In addition, linear correlations were observed between the solubility and polymer-free volume and polymer molecular polarity in triblock copolymers as well as in other conventional polymer families. According to Zimm-Lundberg analysis, the PMMA block segments in the triblock copolymers accelerate water vapor clustering due to the high mobility of PMMA. The mobility of PMMA block segments strongly affected not only physical properties but also the water vapor solubility of the triblock copolymers. The ABA triblock copolymerization composed of PI and PMMA is one of the effective ways to improve the hydrophobic property. (c) 2013 Society of Chemical Industry