Application of Antioxidant in BOPP book cover recycling

Abstract

BOPP (biaxial oriented polypropylene) thin films are commonly used as book covers at schools in Vietnam. At the end of every academic year, a large quantity of BOPP book covers become waste. Therefore, the selective collection and recycling of this material are necessary. The plastic material was separated from paper directly by students from the school, and then it was shredded into small pieces and extruded into pellets with and without antioxidants. The composition of the commercial antioxidant was confirmed by FTIR analysis as a blend of 1:2 by weight of Irganox1010/Irgafos 168. The melt index test showed that after thermal aging of recycled PP pellets at 200 ◦C, they were strongly degraded. However, the addition of antioxidants to the recycled PP samples effectively protected them from degradation. The melt viscosity of recycled PP followed by a mini twin screw extruder also confirmed the protective role of the antioxidant. The larger the quantity of antioxidant used, the more stable the torque or melt viscosity of PP became. The optimal usage of 1% Irganox B 215 can protect PP from further degradation.