| dc.description.abstract | Sisal and Loofah are two amongst a number of
natural fibres that are found in Kenya. While Sisal is
cultivated commercially in large scale plantations,
Loofah grows in the wild. The traditional uses for Sisal
fibre include the making of rope, sacks, carpets, bags
and cushioning upholstery. Loofah fibre is normally used
as washing sponges, pillowing material, filter material
for oil presses and for scouring and cleaning machinery.
Extensive research has been carried out on the
effects of Longitudinally Aligned continuous and Randomly
Aligned Discontinuous Sisal fibres on base materials such
as Mortar, Cement and Epoxy resin. This research has been
conducted within the Departments of technical
Engineering and Civil Engineering of the University of
Nairobi. Mutuli (1979) carried out research on the
mechanical properties of sisal fibre reinforced
composites. While his results on the tensile properties
conformed with the general theory on fibre reinforced
composites, they lacked certain features that would
normally arise at low and high fibre volume fractions.
otieno and Ogango (1991) carrred out some work on the
effects of Loofah fibre on the tensile stress and the
tensile strain of Epoxy reSln. Their results however were
not conclusive.
One of the aims of this research is to determine
the effect of fibre volume fraction on the tensile
strength, tensile strain, and Elastic Modulus of Sisal
reinforced and Loofah reinforced Epoxy resin composites.
Comparison of the results from both the existing theory
and the present work will be done. The volume fraction at
which the composite properties are a minimum or are
critical will be identified. The relationship between the
Multiple Matrix Fracture (M.M.F.) phenomena and the fibre
volume fraction will be determined. The interfacial bond
strength and the fibre critical length will also be
evaluated. In addition the effects of the varying cross -
sectional area of sisal fibre and the differing Poissons
ratios of sisal fibre and Epoxy resin matrix will be
examined.
The present results show that sisal fibre when
used to reinforce Epoxy resin does lead to definate
improvements in the tensile properties of the matrix. The
results also show that designs must be based on specific
fibre volume fractions. Within the M.M.F. range,
containers for liquids will be regarded as having failed
whereas pure structural components may still find use.
In contrast, Loofah fibre reinforcement of Epoxy
resin results into a reduction of the tensile properties
of the matrix. | en |
