Effect of plasma treatment on the morphology, mechanical, and wetting properties of polyethylene/banana fiber composites

In this study, tests were conducted to examine the morphological, mechanical, and wetting properties of thermoplastic composites using banana fiber (BF) an agro-residue as a filler. Plasma-treated polyethylene (PPE) was used as the matrix, and compression molding technique was used for composite preparation. Treated and untreated polyethylene (UPE) banana fiber composites were compared in terms of the interfacial adhesion between the fiber and the matrix. Fibers were added in varying amount (10, 20, 30, and 40 by weight %) into the polymer to investigate the fiber-matrix interaction in each case and also to optimize the composition that would yield improved properties. Morphological properties were studied using scanning electron microscopic (SEM) studies, surface wettability was studied using the contact angle method and FTIR analysis was used to confirm the effectiveness of the functionalization. SEM analysis showed that PPE-BF composites have better interfacial adhesion between the polymer and fiber as compared to UPE-BF composites. Also, PPE-BF showed a maximum of 6% and 25% increment in tensile strength and Young’s modulus. Wettability studies showed that contact angle values got decreased from 93° (UPE-BF20) to 77° (PPE-BF20), which proves the effectiveness of plasma treatment through incorporation of new functionalization (polar groups) on the surface of the polymer in treated composites, and also which shows how the treatment enhanced the interfacial bonding between polymer and fiber.