A Study on Mechanical and Thermal Properties of PLA/PEO Blends

Poly(lactic) acid (PLA) is recognized as one of the polymers with most potential in biodegradable packaging industries. However, PLA is too brittle to be used as thin films. To increase the flexibility of PLA, 1, 3, and 5wt% of polyethylene oxide (PEO) having 100,000 M-w were added into PLA respectively. The blends were compounded and were extruded using a kneader and a twin-screw extruder. The mechanical and thermal properties of PLA blends were analyzed to prove the increase of ductility. In addition, hydrophilic properties, morphologies, and crystallization behaviors of PLA based films were investigated. The addition of PEO into PLA increased the elongation at break, Izod impact strength, hydrophilicity, and the degree of crystallinity, as well as decreased the glass transition temperature (T-g), melting temperature (T-m), cold crystallization temperature (T-cc), and tensile strength of PLA. Significantly, the elongation at break was increased by 4 times at 5wt% PEO loading, while the tensile strength was decreased by 17% only. PLA based films were greatly increased in ductility by blending with PEO.