Environmentally degradable LLDPE/esterified styrene-maleic anhydride (ESMA) blends

LLDPE was blended with esterified styrene-maleic anhydride (ESMA) to improve the environmental degradation characteristics of LLDPE. ESMA was synthesized by esterifying styrene maleic anhydride (SMA) with n-decanol. LLDPE was blended with ESMA (EDP blends) and SMA separately in a single screw extruder by melt mixing. Composition of ESMA was varied from 20 to 40 wt% in the blends. LLDPE grafted with glycidyl methacrylate (LLDPE-g-GMA) was used as compatibilizer to improve the compatibility. Scanning electron photomicrograph (SEM) of cryofractured impact specimens showed significant reduction in domain size and uniform distribution of ESMA in LLDPE matrix in presence of compatibilizer in 70/30 blends. Environmental degradability was assessed by subjecting the films to soil burial test and exposure to buffer solution of different pH. Environmental degradation was followed by measuring the periodic change in weight of the blend samples. Films were exposed to accelerated and natural weathering and photodegradation was assessed by noting the embrittlement time of the film. Films of compatibilized blends fragmented at a faster rate than the films of uncompatibilized blend. Carbonyl index of films subjected to natural weathering was also found to be higher than that for the virgin LLDPE films.