ABSTRACT
The problems of low mechanical properties of composites reinforced with fibres of natural origin have been a source of concern for researchers. Also, the insufficient utilization of bagasse fibres due to its moderate strength has further reduced its potentialities in composite production hence the need to hybridize with other fibres. In this work, the effects of hybridization on the physical and mechanical properties of bagasse/sisal/coir fibre-reinforced epoxy composites have been studied. Test specimens were prepared with different weight fractions of bagasse/sisal/coir in Epoxy resin using hand lay-up method. The samples were characterized for mechanical properties such as tensile strength, flexural strength, hardness and impact strength using ASTM standards. Physical properties such as density and water absorption were also determined. SEM analysis was done to establish microstructure of the fractured samples after the tensile test. The highest tensile strength of 53.25 MPa was obtained for bagasse/sisal/coir at a hybrid ratio of 60/10/30 %, this was 70.1% higher than the monolithic bagasse/Epoxy composite. The composite having composition of 50 %Bagasse/50 % Coir showed aflexural modulus of 3.15 GPa while 60/30/10 % had 4.96 GPa with increase of 50 % over 20% bagasse/Epoxy composite. Hybridization did not improve the hardness of the composites as the highest value was 8.5 RHF at 5% fibre loading of only bagasse. The highest impact strength of 65 J/m2 was obtained for bagasse/sisal/coir at a hybrid ratio of 60/20/20 %. Therefore a crash helmet was fabricated at this composition of fibre blend. The water absorption increases as the fibre loading increases, with the hybrid 60/10/30 % having the highest percentage water absorption value of 10.8 %. This was higher than the bagasse/Epoxy composite with the value of 3.5 % at 20% fibre loading. The SEM analysis showed more fibre pull out for bagasse/coir at 60/40 % than for other hybrid ratios after tensile test. 60/20/20 % gave the best fibre-matrix interaction since there was no fibre fracture or the presence voids. Hence, it can be concluded that proper combination of bagasse/sisal/coir Epoxy reinforced hybrid composite material may have a variety of industrial applications especially where strength and water absorption would be the critical parameters in the design.