Development of Kapok fibre reinforced composites

Kapok fibres have shown to be useful in domestic as well as industrial end - uses. A blend of kapok and cotton fibres at a ratio of 3:2 kapok/cotton has been successfully woven. The fabric has proven to be a good reinforcement to polyester and cashew nut shell liquid ( CNSL ) matrices. Physical and mechanical properties of the fibres and fabric have been determined to assess their suitability and for predicting mechanical properties of the composites materials. Kapoklcotton fibres have been incorporated in polyester and CNSL matrices and the mechanical properties of the composites determined. The composites have been found to possess tensile strengths similar to those obtained from other vegetable fibre reinforced matrices. Experiments carried out show that the tensile strength and specific tensile strength of kapok/cotton fibre - CNSL composite are 48.15 N/mm2 and 0.05 MNm/kg respectively. Kapok/cotton - polyester composite has a tensile strength of 47 N/mm2 and specific tensile strength of about 0.058 MNm/kg. The stiffness obtained in this work were, however, found to be very low. While kapoklcotton - polyester composites showed increases in flexural properties when subjected to accelerated weathering conditions, indicating that there was further crosslinking process of the resin during boiling, CNSL reinforced with kapok cotton fibres had decreasing flexural properties. This implies that molecular scissioq occurred due to water and thermal degradation. The specific flexural strength and modulus of mercerised kapok/cotton fibre - polyester composites have been found to be slightly higher than those of kapok cotton fibre - CNSL composites. Composites subjected to accelerated weathering conditions depicted reduced specific flexural strengths and moduli compared to composites not subjected to accelerated weathering conditions. Also experiments show a decrease in impact resistance with increase in the fibre volume fractions for all the composites and increase in the work done, for the kapok/cotton fibre-polyester composites, obtained in the three - point bend. It is generally felt, therefore, that kapok fibre in blends with cotton fibre can be used as reinforcements to thermosetting polymeric resins and produce fairly tough composites materials. And that, kapok/cotton - CNSL composites could suitably be processed as they are likely to make use of the locally available agricultural waste. Both, Kapok fibre and CNSL are abundantly available in Tanzania