Novel Eco-Friendly Biocomposites: Biofiber Reinforced Biodegradable Polyester Amide Composites—Fabrication and Properties Evaluation

Lignocellulosic natural fibers like sisal and pineapple leaf fiber (PALF) can be incorporated in polymers based on biodegradable polyester amide matrix, BAK 1095 for achieving desired properties and texture in the resulting biocomposites. But high level of moisture absorption, poor wettability and insufficient adhesion between untreated fiber and the polymer matrix led to debonding with age. In order to improve the above qualities, various surface treatments of sisal fiber like mercerization, cyanoethylation, acetylation, bleaching and vinyl monomer (acrylonitrile) grafting are carried out which results in improved mechanical performance of sisal-BAK composites. Mechanical properties like tensile and flexural strength are optimum at a fiber loading of 50 wt%. Among all modifications, alkali treatment and acetylation result in improved properties of the composites. Alkali treated sisal composite shows about 20% increase in tensile strength and acetylated sisal composite shows about 14% increase in flexural strength compared to the control, i.e., untreated sisal based biocomposites. From the biodegradation study, we find that after 60 days of soil burial about 1% weight loss is observed for BAK whereas acetylated sisal-BAK composite shows maximum weight loss (22%). It also shows maximum decrease in flexural strength (47%) after 15 days of sisal burial. A comparative account of properties of PALF-BAK and sisal-BAK biocomposites is also given. Scanning electron microscopic studies were carried out for better understanding of fiber-matrix adhesion in biocomposites.