Tribo Performance of T-bfrp Composite Subjected to Dry/Wet Contact Conditions - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 300

Chapter 27
tribo Performance of t-BFrP Composite subjected
to dry/Wet Contact Conditions
Umar Nirmal, Jamil Hashim, Dirk Rilling, P.V. Brevern, and B. F. Yousif
iNtroduCtioN
Recently, new and more stringent environmental regulations coupled with the deple-
tion of oil resources have evoked a concern among researchers to find a substitute for
synthetic fibers in polymeric composites (Yousif and El-Tayeb, 2008a). As an alter-
native, natural fibers are becoming an attractive alternative due to their advantages
over the synthetics such as recyclability, biodegradability, renewability, low cost, light
weight, high specific mechanical properties, and low density (Corbiere et al., 2001;
Gowda et al., 1999; Joshi et al., 2004; Yousif and El-Tayeb, 2008a; Wambua et al.,
2003). Nowadays, applications of natural fiber reinforced polymeric composites can
be found in housing construction material, industrial and automotive parts (Baiardo et
al., 2004; Huda et al., 2008; Liu et al., 2004; Nishino et al., 2003).
It is known from the literature that, untreated oil palm (Yousif and El-Tayeb, 2007a,
2008a, 2010), sugarcane (El-Tayeb, 2008a, 2008b), banana (Pothan et al., 2003) and
coir (Yousif, 2008) fibers have very poor interfacial adhesion strength with the matrix
by nature. The poor interfacial adhesion is due to foreign impurities/substances which
prevent the matrix to bond firmly with the fibers. Interestingly, betelnut fibers have
many tiny hairy spots termed trichomes which protrude from the outer layer of the
fiber surface (Nirmal and Yousif, 2009). The presence of trichomes may results in high
interfacial adhesion with the polymer matrix and may prevents pulling out processes
during tribological and single fiber pullout tests (SFPT).
From the tribological point of view, few works have been pursued on jute (Thomas
et al., 2009), cotton (Hashmi et al., 2007), oil palm (El-Tayeb, 2008b; Yousif and El-
Tayeb, 2007a, 2008a), sugarcane (El-Tayeb, 2008a, 2008b), coir (Yousif, 2008) and
bamboo (Tong et al., 1998, 2005) fibers regarding their usage for tribo-polymeric com-
posites. For instance, wear and frictional characteristics of oil palm fiber reinforced
polyester composite (Yousif and El-Tayeb, 2007a, 2008a) revealed that oil palm fibers
enhanced the wear performance of polyester by three to 4-folds. This was due to the
presence of oil palm fibers at the surface of the composite forming a mixed layer of bro-
ken fiber and polyester debris which protected the polyester regions during the sliding.
Considering fiber orientation, the effect of sugarcane fiber has been studied on
tribo-characteristics of polyester composites (El-Tayeb, 2008a). It has been found that
fiber mats oriented parallel to the sliding direction showed lower wear performance
than fibers oriented anti-parallel under the same test conditions. This was because in
the parallel orientation, the path ahead of the wear debris is exposed, thus easing the