J. Rout et al., The influence of fiber surface modification on the mechanical properties of coir-polyester composites, POLYM COMP, 22(4), 2001, pp. 468-476
Coir, an important lignocellulosic fiber, can be incorporated in polymers l
ike unsaturated polyester in different ways for achieving desired propertie
s and texture. But its high level of moisture absorption, poor wettability
and insufficient adhesion between untreated fiber and the polymer matrix le
ad to debonding with age. In order to improve the above qualities, adequate
surface modification is required. In our present work, fiber surface modif
ication was effected through dewaxing, alkali (5%) treatment, aqueous graft
copolymerization of methyl methacrylate (MMA) onto 5% alkali treated coir
for different extents using CuSO4 - NaIO4 combination as an initiator syste
m and cyanoethylation with a view to improve the mechanical performance of
coir-polyester composites. Mechanical properties like tensile strength (TS)
, flexural strength (FS) and impact strength US) of the composites as a fun
ction of fiber loading and fiber surface modification have been evaluated.
Composites containing 25 wt% of fiber (untreated) improved tensile and flex
ural strength by 30% and 27% respectively in comparison to neat polyester.
The work of fracture (impact strength) of the composite with 25 wt% fiber c
ontent was found to be 967 J/m. The elongation at break of the composites e
xhibits an increase with the introduction of fiber. All types of surface mo
dification result in improved mechanical properties of the composites. Sign
ificant improvement in mechanical strength was also observed for composites
prepared from 5% PMMA grafted fiber.