'GREEN' COMPOSITES USING MODIFIED SOY PROTEIN CONCENTRATE AND WOVEN FLAX FABRIC

摘要

"Green" composites made from environment-friendly, fully biodegradable resins and fibers offer an attractive alternative to the conventional composites made using petroleum-based or synthetic resins and fibers that do not degrade over many years. Woven fabric reinforced composite offer several advantages over unidirectional composites such as good stability in mutually orthogonal warp and weft direction, more balance properties in the fabric plane and better impact resistance. This paper discusses two-dimensional 'green' composites prepared using glutaraldehyde modified soy protein concentrate (MSPC) and flax fabric. Soy protein concentrate (SPC) polymer has low tensile properties, poor moisture resistance and is brittle. SPC polymer with 15% glycerin, as an external plasticizer, exhibited fracture stress and Young's modulus of 17 MPa and 368 MPa, respectively. In the present study, SPC was cross-linked with glutaraldehyde (GA) to increase its tensile properties and improve its processability as a resin to manufacture flax fabric reinforced composites. SPC forms a miscible blend with GA and reacts with free amine groups in the protein. MSPC showed 35% increase in fracture stress and 55% increase in Young's modulus as well as improved moisture resistance compared to SPC. Besides mechanical properties, MSPC was also characterized for its thermo-gravimetric and dynamic mechanical properties. Composite laminates, approximately 1 mm thick, were made using flax fabric and MSPC polymer. Composite specimens were prepared with two different orientations, namely, 0° and 90°. Composite specimens exhibited a fracture stress of 56 MPa and 42 MPa in the longitudinal and transverse directions, respectively. The laminates exhibited a Young's modulus of 1.3 GPa and 1.09 GPa in the longitudinal and transverse directions, respectively.