Authors

Abstract

In this investigation, the development of composite materials was achieved
in two steps. The first, by the hybridization of the resin matrix with different
elastomers to prepare binary polymer blends, these blends have been synthesized
by mixing either of (Nitrile Rubber(NBR), Styrene Butadiene Rubber(SBR) and
Butadiene Rubber(BR)) with the Epoxy resin(EP) and Unsaturated polyester
resin(UP). The second step is reinforcement of the polymer blends with 30% of
two types of fibers. The first, is by using E-glass fibers alone while the second by
utilizing a hybrid of E-glass fibers with Kevlar fibers (type-49). Different weight
percentages (5, 10, 15,…., 50)% of those elastomers were mixed with each of EP
and UP. The optimum mixing ratios (OMR) of those blends have been selected
depending on achieving acceptable macro miscibility, best adhesion between two
phases and highest impact strength (I.S) of the resulting blends. The values of
(I.S) increased gradually with increasing of rubber content until its maximum
value (OMR), and then it goes down as the percentage of the elastomer
increases. Five blends with (OMR) were prepared : EP/NBR(80/20)% ,
EP/BR(70/30)% , UP/NBR (90/10)%, UP/SBR (90/10)% , UP/BR (90/10)%,
while a phase separation of SBR rubber from EP resin has taken place at all
ratios; then, these blends were reinforced with single and hybrid fibers. Impact
test was carried out at different environmental conditions to have full description
about the mechanical behavior of those blends and their composites under effect
of the impact stress.