Effect of mercerization on the properties and biodegradation behavior of LDPE and LDPE/PHB hybrid composites filled with castor bean cake

Abstract

ABSTRACT The aim of this study is to evaluate the effect of mercerization of castor cake on the tensile and biodegradation behaviour of LDPE and LDPE/PHB composites. Polymer composites filled with raw castor cake (CC) and castor cake treated with 5% NaOH solution (MCC) were developed and the tensile and biodegradation behaviour of the materials obtained were evaluated. The incorporation of mercerized fibers to polymeric matrices generated materials with an elastic modulus superior to that of LDPE and tensile strength values close to that of LDPE. The biodegradation rates of the polymer composites increased the addition of fibers. However, alkali-treated fibres had a less pronounced effect biodegradation rates of the polimeric composites, due to the lower tendency of mercerized fibers to absorb water. The 85/10/5 LDPE/PHB/CC composite showed greater mass loss, 3.1%, than the 85/10/5 LDPE/PHB/ MCC composite, respectively, 0.9%, in 180 days.