Preparation and Characterization of Reactive Blends of Poly(lactic acid), Poly(ethylene-co-vinyl alcohol), and Poly(ethylene-co-glycidyl methacrylate)
Phromma Warangkhana (1), Jana Sadhan C. (2), Magaraphan Rathanawan (1)*
(1) Chulalongkorn University, Petroleum and Petrochemical College - Bangkok - Thailand, (2) The University of Akron, Department of Polymer Engineering - Ohio - USA
The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (E-GMA) were prepared. The role of E-GMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and that of E-GMA was varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscope, and mechanical properties by dynamic mechanical analyzer, pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The mixtures PLA/E-GMA and EVOH/E-GMA showed dispersed droplets of E-GMA which led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of E-GMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.