Poly (methacrylic acid) (PMAA) copolymers with uniform polystyrene (PS) side-chains were synthesized through the macromer technique. The graft copolymers (PMAA-g-PS) were purified by extraction with water and hot cyclohexane, and were then characterized by gel permeation chromatography, infra-red spectrophotometry and 1H nuclear magnetic resonance spectroscopy. The average grafting number was determined to be 3-7, and decreases with increasing conversion. The graft copolymers showed good emulsifying properties and high water absorbency, and can be used as a good compatibilizer for blending polystyrene with epichlorohydrin rubber (CHR). Only 2-3 wt% of the graft copolymer based on the blend was needed to enhance the mechanical properties of the blends, and the blends with weight ratio of PS/CHR = 3/7 to 5/5 behave as good thermoplastic elastomers. When PMAA-g-PS was mixed with polyoxyethylene (PEO) grafted with PS in molar ratio of PEO/PMAA = 1, a thermoplastic intermolecular complex membrane was formed. This behaved as a chemical valve, as its permeability can be controlled reversibly by changing the pH value.
Посилання на статтю:
Synthesis and properties of amphiphilic poly (methacrylic acid ) copolymers possessing uniform polystyrene side-chains / Hong-Quan Xie* and Yong Liu // Polymer. – 1993. – Vol 34. – P. 182-186.