Development and Testing of High Performance Nylon12 (PA12) Based Natural Fiber Composites

Kenaf based nylon 12 (PA12) composites were successfully made using hydroentanglement and film stack compression molding. The combination of natural fibers with an engineering polymer with a relatively low melting temperature can potentially have high strength and modulus composites. The chopped kenaf fibers were treated in a NaOH solution. The NaOH treatment is used to improve the roughness of the surface and also expose cellulose fibers within the fibers to help improve bonding with the resin. Tensile tests of samples with treated and untreated fibers with a fiber weight fraction of 40% show that the treated fiber composite has an improvement of 13% and 18% in its strength and modulus respectively. The resulting fibers were used to make preforms using hydroentanglement process. The process of hydroentanglement is typically used in making paper products. The use of this process to make composite materials using chopped fibers is a very unique approach adopted for this research. Three different fiber weight fractions were looked at namely 40%, 50% and 60%. Tensile and flexure testing of the samples showed a consistent increase with an increase in the fiber weight fraction. Morphological characterization of the fibers showed that treatment removed excess fluff and dirt and also had striations on the fiber which would lead to better fiber wet-out. SEM images of the fractured surface of the sample with 50% by weight of kenaf fibers showed that there was some fiber bundling as expected leading to dry zones within the composite which could potentially lead to crack initiation. The novelty of the research is developing preforms using chopped natural fibers using hydroentanglement process and the ability to combine these natural fibers with low melting point PA 12 leading to obtaining high strength composite without compromising the structural integrity of the kenaf fibers.