GAMMA-RAY INDUCED GRAFT-COPOLYMERIZATION OF METHYL-METHACRYLATE ONTO POLY(BETA-HYDROXYNONANOATE)

Copolymers of poly(3-hydroxy-nonanoate), PHN, with methyl methacrylate , MMA, were prepared using Co-60-gamma irradiator. The bulk solutions of PHN in MMA were prepared at different PHN feed concentration and th ey were irradiated to 8.5 kGy at room temperature. Polymer fractions o btained by solvent-nonsolvent fractional precipitation were carefully characterized using gel permeation chromatography (GPC), nuclear magne tic resonance spectroscopy (NMR), and thermal gravimetric analysis (TG A) techniques. High copolymerization yield was observed and the copoly mer compositions obtained from the TGA measurements were consistent wi th the NMR results. PHN contents of the copolymer samples changed from 5 to 35 wt.-%. The strain at break and tensile strength values of cop olymers were between the values of their respective homopolymers. It w as observed that pure copolymer samples showed up to 13% strain at bre ak.