Mechanical and Thermal Properties of Silane Treated Pineapple Leaf Fiber Reinforced Polylactic Acid Composites

Abstract

In this work, the mechanical and thermal properties of pineapple leaf fiber (PALF)/poly (lactic acid) (PLA) composites were studied. Pineapple leaf fibers were pretreated with 4 %wt sodium hydroxide solution followed by various silane solutions i.e. γ-(aminopropyl) trimethoxy silane (APS), γ-methacrylate propyl trimethoxy (A174) and bis [3-(triethoxysilyl) propyl] tetrasulfide (Si69). FTIR results show a significant functional groups of C=O and C=C of methacrylic group, NH2group and Si-O which are the characteristic of these silane coupling agents. SEM micrographs of pretreated PALF showed a rough surface while untreated and silane treated PALF revealed less roughness. It was found that the tensile strength at break of PLA is 56 MPa and tensile strength of composites decreased when fiber content increased. The tensile modulus of silane treated PALF composites were higher than PLA, whereas their impact strength were similar to PLA. Si69 treated PALF showed lower impact strength compared to the others silanes treated fiber which indicates more phase separation between fiber and matrix. This is related to high percentage of crystallinity of composite from Si69 treated fiber. It was also found that the addition of PALF did not change the glass transition temperature and melting temperature of PLA while the percentage of crystallinity increases as the fiber content increased. In addition WAXS study of composite from Si69 treated fiber reveals sharp crystalline peaks of PLA while the others silane treatments show amorphous characteristic of PLA.