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CHAPTER 2
LITERATURE REVIEW
2.1 Oil Palm
The oil palm is a tropical palm tree that has two species. The African oil palm
(Elaeis oleifera) is native to West Africa, occurring between Angola and Gambia,
while the American Oil Palm (Elaeis oleifera) is a native to tropical Central
America and South America. (Unknown, March 2012).
The high productivity of the oil palm at producing oil (as high as 7,250 liters per
hectare per year) has made it the prime source of vegetable oil for many tropical
countries. It is also likely to be used for producing the necessary vegetable oil for
biodiesel, an example being a planned refinery Darwin, Australia which will
import the palm oil from Indonesia and Malaysia (Kamarul Azlan Abd. Hamid,
May 2008)
The oil palm originated in West Africa but has since been planted successfully in
the tropical regions within 20 degrees of the equator. There is evidence of palm
oil use in Ancient Egypt. In the Republic of Congo, or Congo Brazzaville,
precisely in the Northern part, not far from Ouesso, local people produce this oil
by hand. They harvest the fruit, boil it to let the water part evaporate, then
pressing what is left into collect the reddish, orange colored oil.(Unknown, March
2012)
The world's largest producer and exporter of the palm oil today is Malaysia,
producing about 47% of the world's supply of palm oil. Indonesia is the second
largest in the world producer of palm oil producing approximately 36% of world
palm oil volume. Both nations are expanding their palm oil production capacity
and the market continues to grow (Kamarul Azlan Abd. Hamid, 2008).
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Worldwide palm oil production during the 2005-2006 growing season was 39.8
million metric tons, of which 4.3 million tons was in the form of palm kernel oil.
It is thus by far the most widely-produced tropical oil, and constitutes thirty-four
percent of total edible oil production worldwide. Oil palm is one of the most
abundant, unutilized waste biomass from plantation in South-Asia. (Unknown,
March 2012)
2.1.1 Oil Palm Frond
Plate 2.1: Oil palm frond
A palm branch (or palm frond or palm stem), usually refers to the leaves of the
Arecaceae (sometimes known by the name Palmae). The oil palm frond (OPF) is
collected during pruning and replanting activities. The availability of fronds
during the pruning activity was calculated using an estimate of 10.4 tones ha-1
,
which currently gives an average of 6.97 million tons per year. Meanwhile, it was
estimated at an average of 54.43 million tons per year oil palm fronds will be
available during the replanting process in the year of 2007- 2020 (Rafidah J, et al,
2007).
The cell walls of OPF are composed mainly of cellulose, hemicelluloses and
lignin. In addition to those three main components, several percent of ash and
extractives are included. Among those components, cellulose and hemicelluloses
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are polysaccharides, which are easily decomposed and metabolized by wood-rot
fungi. In the constituent analysis of wood, when lignin is selectively removed, is
obtained holocellulose. Holocellulose can be thought of as the total of cellulose
and all hemicelluloses (Kamarul Azlan Abd. Hamid, 2008).
2.1.2 OPF As An Alternative Source of Particle Board
Plate 2.1.2: Plots of waste of oil palm frond
The rapid increase in the world’s population has caused a rise in demand for wood
and wood products (Uysal, 2005). The increasing prices of timber and its shortage
have affected the wood-based industries in the world. The ever-increasing
manufacturing costs and uncertainty in wood supply in some regions, due to
restrictions on logging and inadequate forest resources, has raised concerns over
future wood supplies. The forest may no longer be able to supply the wood in a
sustainable way anymore. Thus to overcome this research and development
activities in many countries around the world, including Malaysia, have focused
on composites, using non- wood resources from agricultural residues as the
alternative source of raw material. Non-wood lignocellulosic composites are
becoming attractive in commercial and non-commercial applications.(Rasat, et al,
2011)
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Organic natural fibers are increasingly being investigated for various usages in
many structural and non-structural applications. Malaysia produces a large
quantity of agricultural waste such as oil palm fiber Elaeis guineensis. It has
generated about 18 million tons (dry basis) a year (calculated based on 1992) of
world frond production (Office Agricultural Economics, 1994). Furthermore, the
advantages of these fibers that they are renewable, non- abrasive, cheaper, and
abundant.
Oil palm fronds, which can be obtained all year round, can answer to overcome
the problem of raw material because they appear to be the most viable alternative
to be utilized as value-added products for the wood based industry. Considering
the above mentioned facts, manufacture and fundamental properties of palm frond
particle board were investigated and the suitability of oil palm frond as a raw
material for manufacturing particle board is discussed.
2.2 Particleboard
Plate 2.2: Sample of particleboard
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The particle board can be differed based on the size of particle. There are several
types of particle such as: fiberboard, oriented strand board (OSB), medium
density board (MDF) and others. Particle board is a panel product made by
compressing the small portion of wood while simultaneously bonding them with
adhesive (Youngquist, 1987)
The wood particle board industry grew out of the need to dispose the large
quantities of sawdust, planner shaving and to a lesser extend the use of residual
and other relatively homogenous waste material produced by other wood
industries. Particleboard is produced by mechanically reducing the material into
small particles, applying the adhesive to the particle and consolidating to a loose
mat of the particle with a head and pressure into a panel product.
2.2.1 History of Particleboard
In 1941, a commercial plant in Germany first manufactured particle board.
Particle board was sought as a replacement for expensive and scarce plywood
materials. Originally, manufacturers used wood waste material for particle board.
Today, manufacturers are considering the use of landfill products, such as
agriculture waste for particleboard.
It was found that better strength; appearance and resin economy could be
achieved using more uniform, manufactured chips. Manufacturers began
processing solid birch, beech, alder, pine and spruce into consistent chips and
flakes. These finer layers were then placed on the outside of the board, with the
central section composed of coarser, cheaper chips. This type of board is known
as three-layer particleboard. More recently, graded-density particleboard has also
evolved. It contains particles that gradually become smaller as they get closer to
the surface (Unknown, November 2007)
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2.2.2 Properties of Particleboard
There are various characteristic of particleboard such as cheaper, denser and more
uniform that conventional wood and plywood is substituted for them when
appearance and strength are less important than cost. However, the particleboard
can be more attractive by painting or using of wood veneer that are glued onto the
surface that is visible. The strength of the board depends on its density, thickness
with layer and graded structure and adhesive. The stability of board is quite good
with working properties generally good where it is easy to saw, drill and edge. A
major disadvantage of particleboard is that it is very prone to expansion and
discoloration due to moisture, particularly when it is not covered with paint or
another sealer. Therefore, it is rarely used outdoors or places that have high level
of moisture. Particleboard is commonly use in all types of building construction,
wall, floor panel, door and furniture. (Unknown, November 2007)
2.3 Phenol Formaldehyde
Plate 2.3: Phenol formaldehyde
Phenol Formaldehyde is two component synthetic glue. Phenol (with the chemical
formula C6H5OH) is reacted with formaldehyde (CH2O) under control
temperature conditions to produce a thermosetting (heat hardening) resin. This
resin is a new chemical entity which possesses properties that are completely
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distinct from those of either phenol or formaldehyde, with the formaldehyde
converted to stable methylene linkages which do not break down under exterior
end use conditions (CertiWood Technical Centre, 2011).
Phenol formaldehyde resins as a group are formed by a step growth
polymerization reaction that can be either acid or base catalyzed. Since
formaldehyde exists predominantly in solution as a dynamic equilibrium of
methylene glycol oligomers, the concentration of the reactive form of
formaldehyde depends on temperature and pH (Anonymous, April 2012). Phenol
is reactive towards formaldehyde at the ortho and para sites (sites 2, 4 and 6)
allowing up to 3 units of formaldehyde to attach to the ring. The initial reaction in
all cases involves the formation of a hydroxymethyl phenol.
HOC6H5 + CH2O → HOC6H4CH2OH
The hydroxymethyl group is capable of reacting with either another free ortho or
para site, or with another hydroxymethyl group. The first reaction gives
a methylene bridge, and the second forms an ether bridge:
HOC6H4CH2OH + HOC6H5 → (HOC6H4)2CH2 + H2O
The diphenol (HOC6H4)2CH2 (sometimes called a "dimer") is called bisphenol F,
which is itself an important monomer in the production of epoxy resins.
Bisphenol-F can further link generating tri- and tetra-and higher phenol
oligomers.
2 HOC6H4CH2OH → (HOC6H4CH2)2O + H2O