Civil Engineering Reference
In-Depth Information
surface area and transfers it to the reinforcement material. Three main types of
vegetable fibrous composites can be categorized: (1) composites in which the fibre
serves as a filler in commodity thermoplastics. (2) composites in which longer
fibres enhanced with compatibilizers and other additives to obtain additional
strength and toughness in thermoplastics. (3) composites in which fibres are used
with thermosetting resins as designed elements within engineered components
(Suddell
2008
). Composites using natural fibres and bio-based resins will see
explosive development within the next ten years (Suddell
2008
). As extensive
reviews are available in the literature which covers in great detail of the raw
materials, manufacturing methods, properties of composites reinforced by vege-
table fibre, this subsection, therefore, provides a brief summary of the outcome
research in vegetable fibrous composites.
Tradition reinforcement by fibres is often for structural strength purposes for
providing load carrying capacity, toughness, flexural strength and resistance to
cracking and defections. Some vegetable fibres present good tensile strength which
can be integrated in the materials to carry the load and to produce high stiff, high
strength and good thermal fibre-reinforced composites suitable for different
building purposes. The greatest advantage of using vegetable fibres as reinforce-
ment in polymer matrix is that they can promote new classes of biodegradable
composites with improved mechanical properties.
Moreover, modern technologies for vegetable-fibre-reinforced composites
modify the properties of the material in more predictable, measurable and eco-
nomical ways for specific applications in technological and environmental
advantages and challenges (Vassilev et al.
2013
). For example, oil palm fibre has
been used to improve thermal, hygroscopic and insulation property of laminate
composite (Hariharan and Khalil
2005
). Abdul Khalil et al. (
2012
) provided a
critical review of the most recent developments of bamboo-fibre-based reinforced
composites with low cost.
Despite various purposes and modern technologies, the major contribution of
the vegetable fibres has always been towards increasing the mechanical strength of
the materials. The mechanical behaviour of the composite is greatly depending on
the fibre properties and the percentage of fibre added as well as the manufacturing
process. The main goal of fibre processing is to remove pectin and lignin and
separate fibre bundles. This will increase the contact surface area of the fibre for
chemical and/or mechanical bonding with matrix phase. The degree of chemical
and/or mechanical bonding between fibre and matrix determines the strength of the
overall composite (Agopyan et al.
2005
; Khalil et al.
2012
; Li et al.
2000b
; Jawaid
and Khalil
2011
; Graupner et al.
2009
; Merta and Tschegg
2013
; Pacheco Torgal
and Labrincha
2013a
,
b
; Pacheco Torgal et al.
2013
). The final manufactured
products largely depend on process parameters used to process the fibres and
manufacture the composites. The composites can be produced in various ways
using hot pressing, extrusion, injection moulding, compression moulding, etc.
Broadly speaking, there are two approaches and the products fall into two groups:
The first one is based on the production of thin sheets or mats. The second is based
on the production of composites for different types of building components, such
