Graft copolymerisation of methyl methacrylate onto a bacterial polyester containing unsaturated side chains

Poly(3-hydroxy alkanoate) containing unsaturated side chains was produced b y feeding Pseudomonas oleovorans with soybean-oil acid (PHA-soybean). The c omposition of PHA-soybean were found to be 10 mol-% of unsaturated side cha ins with the saturated hexanoate, octanoate and decanoate units. Methyl met hacrylate (MMA) was thermally grafted on PHA-soybean in the presence of ben zoyl peroxide, Fractional precipitation was used to isolate the graft copol ymer from related homopolymers. PHA content in copolymer samples was betwee n 15 to 30 mol-%. Graft copolymer samples were kept in hydroquinone to prev ent post polymerization leading to crosslinking in a day under laboratory a tmospheric conditions. Copolymer characterization was performed using GPC a nd NMR techniques. Thermal analysis of the graft copolymer indicated the de composition and glass transition temperatures of the PHA and PMMA segments of the graft copolymers. They also showed elongation at break in the range 10 to 21 related to the plasticizer effect of the biopolyester segments.