JST Vol. 21 (1) Jan. 2013 - Pertanika Journal - Universiti Putra ...

Aji, I. S., Zinudin, E. S., Khairul, M. Z., Abdan, K. and S. M. Sapuan
use of these natural fibres, including low cost, light weight, environmental friendliness, ease
of formulation, availability in most countries, specific strength, relative non-abrasiveness to
processing equipments (George et al., 2001; Lee et al., 2005; Li et al., 2008; Aji et al., 2009),
just to mention a few. Meanwhile, some marketable reasons in replacing synthetic fibres with
natural ones include low cost (~1/3 of glass fibres), lower density (~1/2 of glass), as well as
acceptable specific strength properties and enhance energy recovery, CO 2 sequesterization and
its natural tendency to degrade (Kim et al., 2007).
Electron beam irradiation (EBI) technique is gaining increased attention as a surface
modifier and properties enhancer of various polymers, natural and synthetic fibre composites.
This is because the process is devoid of wet conditions, while its clean and cold process gives
rise to energy saving and high-speed enhancement of properties.
It has been reported by Han et al. (2006) that the presence of inner pore structure of natural
fibril can be maintained by the use of EBI treatment unlike its destruction when fibres undergo
alkali treatment. These pore structures can serve as insulators and collision absorbers when
such composites are used in automobile and structural part. Similarly, to achieve superior
strength in natural fibre composite, there is a basic need to improve fibre/matrix adhesion,
and the use of adequate coupling agents and EB-Irradiation is one of the ways to achieve this
(Czvikovszky, 1996). However, hybridization has been shown to be one of the ways to achieve
this objective (Aji et al., 2011).
This work presents the response of Hybridized Kenaf/PALF reinforced HDPE Composite’s
tensile properties to EB-Irradiation without the addition of cross linking agents to develop an
environmentally friendly bio-composite.
MATERIALS AND METHOD
Materials
Pineapple leaf (Ananas comosus) was bought from Perniagaan Benang Serat Nanas M&Z,
with the source from Johor pineapple plantation, Malaysia. It was manually decorticated from
the PALF variety of “Josephine”. Kenaf (Hibiscus cannabinus) of variety V36, which was
purchased from KEFI Malaysia Sdn. Bhd., was utilized in this research. These fibres were
reinforced with high density polyethylene, which was also purchased from KEFI Malaysia.
The tensile strength and modulus of HDPE used as tested by us using ASTM D-638 was 29.44
MPa and 287.70 MPa, with a melting point of 180 – 240 o C, in addition to a melt mass flow
rate of 0.10/10min (190 o C/2.16 kg) and a density of 0.95 g/cm 3 .
Preparation of the Composite
The fibres of Kenaf and PALF (at a ratio of 1:1) and the fibre length of 0.25 mm were utilized
for this particular experiment. The fibres were carefully and thoroughly mixed together in
a Brabender Plasticod at a fibre loading of 50%, in 190 o C, at 40 rpm processing speed and
for 25 minutes operating (Aji et al., 2011). The mixed composite obtained from the internal
mixer was cut into pellets and compressed in a compression-moulding machine set at 170 o C,
with 7 min preheat, 5 min full press, 10 seconds of venting process, and 5 min cooling of the
136 Pertanika J. Sci. & Technol. 21 (1): 283 - 298 (2013)