PROPERTIES OF RICE STRAW FIBREBOARD BOUND WITH RECYCLED LOW DENSITY POLYETHYLENE (LDPE)

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Department of Environmental Design

ABSTRACT
The environmental impact of deforestation and the non biodegradability of synthetic polymer as a major product of household waste, necessitate the need to look into agricultural residue and low density polyethylene (LDPE) as an alternative source of raw material for the production of fibreboard panels. This study investigated the properties of fibreboard made from Rice Straw (as main matrix) and LDPE (as filler material and binder), with a view to establishing their suitability for use as panels in the Construction Industry. The composite were produced using the dry blend/hot press method. Processed Rice Straw was mixed with shredded LDPE from sachet water at 20%, 30%, 40%, and 50% replacement levels, based on the dry weight of the straw. The mixed material was pressed at an optimum temperature and pressure of 170oC and 1.4N/mm2 respectively in Moore’s Hydraulic Press machine. Ten test samples of nominal size 200mm x 200mm x 6 mm were produced at each replacement levels. The test samples were evaluated for both physical and mechanical properties according to the relevant standards. The results showed that the density ranged from 800kg/m3 to 1000 kg/m3. The mean value for surface absorption was observed to increase from 149mm for samples with 20% replacement level to 200mm for samples with 50% polymer content. As the concentration level of LDPE increases, it was generally observed that both thickness swell and moisture absorption decreases in value from 31% to 4% and 57% to 24% respectively. The bending strength properties showed a non linear behavior with the lowest mean value of 20N/mm2 for samples with 20% replacement level and the highest mean value of 43N/mm2 for samples with 30% Polyethylene content. The Internal Bond property was observed to vary from 1.07N/mm2 to 3.07N/mm2 for samples with 20% and 50% replacement levels respectively. Similar trend was observed with regards to the screw holding properties. The screw holding properties vary from 720N to 1220N for samples with 20% and 50% polymer content respectively. However the result on bending stiffness was observed to be unsatisfactory. The maximum mean value recorded for the samples at 30% replacement level was 2279N/mm2, which was 16% lower than the 2700N/mm2 specified by BS 622-5: 2003. The study concluded that samples with 30%, 40% and 50% Polyethylene replacement levels met the requirements set out by BS 622-5: 2003. It was therefore recommended that fibreboards made with these materials can be used for interior furniture works, wall paneling and ceiling board.