Abstract:
In the present work, different type~ of coir fiber reinforced polypropylene (PPj
composites were preparcd by injection moulding technique. To prepare improved coirpolypropylene
composiles, various typcs of chcmical trcatments were carried out.
Unbleached raw coir fiber was modificd by o-hydroxybenzene diazonium chloride and
sodium periodate oxidation. Rcaction parameter (pH) of o-hydroxybenzene diazonum
chloridc was varied al3, 7 and 10.5. Coupling reaction on oxidizcd coir was carried out
using 2,4-dinitrophenylhydrazinc and urca. FT-IR spcctroscopic analyses wcre donc for
all chcmical treatments and the result~ showed the evidence of positive reactions. The
effects of2,4-dinitrophcnylhydrazine, o-hydroxybenzene diawnum chlor,ide and urea on
the physico-mechanical properties of the composiles were studied. The effc<:tsof fiber
content on the physico-mechanical propertics of composites were also studied by
preparing composites with different fiber content (10,15,20 and 25 wt%) for each type
of composite. Mechanical properties (tensile strength, tensile modulu~,flexuml strength,
flexural modulus, charpy impact strength, hardness and water absorption) were
measured for all raw and treated eoir oompo~iles.Improved mechanical properties were
obtained for all treated composites over untreated raw coir reinforced polypropylene
composites. Scanning electron micrographs of the composites were taken to investigate
the inlerfacial adhesion and bonding between the fiber and polypropylene matrix
resulting from the various chemical treatments. Improved interfacial inlemclions were
found for treated composites than untreated composites. Water absorption te~ls were
carried out of all eompositcs to investigate thc effect of chemical treatment on the
moisture absorption characteristic of hydrophilic coir in the eoir-polypropylene
composites, which has direct effect on the dimensional stability of the composites.
Reduced water absorption was fonnd for oxidized ooir-polypropylene composites. 0-
hydroxybenzene dia;;onum chioridc trealcd cOlr composites und 2,4-
Dinitrophenyihydrazine treated oxidized and urea treated oxidized coir-polypropylene
I
composites. urea treated specimens yielded the bcst set of mechanical properties. B~ed
r
on fiber loading, 25% fibcr reinforced composites had the best sct of mechanical
properties among all composites manufactured.
