Studies on Mechanical, Barrier, Optical and Physical Properties of LDPE/PLA Blend for Packaging Films

By : K.P. Arul Kumar, S. Soundararajan

Page No: 491-502

Abstract
LDPE was melt blended with PLA (90:10, 80:20, 70:30, 60:40, 50:50% (wt%) ) using a twin screw extruder with LDPE-g-MAn compatibilizer (3%) and Benzophenone 3% (Photo degradable additive). Tubular blown films were made using a blown film extruder. The films obtained were subjected to various mechanical tests, Optical tests, Barrier properties (Oxygen gas permeability and WVTR). The tensile strength increased with the increase in percentage of PLA in the machine direction up to 40% of PLA and then decreased. In the transverse direction the strength was lowered with increase in percentage of PLA. Elongation at break was lower for certain formulations. Tear strength, Burst strength and the dart impact strength was lowered. The dynamic and static coefficient of friction values were increased with increase in percentage of PLA. WVTR was nearly similar as that of pure LDPE up to 80:20 % (LDPE: PLA) and then the values started decreasing. Oxygen gas permeability was also decreased with increase in percentage of PLA. Luminous transmittance was decreasing and the Haze was found to be increasing with increase in percentage of PLA. SEM of 60:40% & 50:50% LDPE-PLA images show the blends are compatible and dispersed well in presence of compatibilizer. The LDPE[1]PLA with benzophenone additive (3 wt%) will be highly Photo/Bio-degradable and hence will not contaminate/pollute in the environment.

Authors :
K.P. Arul Kumar and S. Soundararajan : Department of Plastics Technology Central Institute of Plastics Engineering and Technology, Guindy, Chennai -600032, India.