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WOOD COMPOSITE POWDER PLASTIC RECYCLING TECHNOLOGY USE ALTERNATIVE WASTE WOOD AND PLASTIC
INTRODUCTION
Due to the unique nature and characteristics, wood is the material most widely used for construction purposes. The ever-increasing demand for wood and forest potential of dwindling demand the use of wood in an efficient and expedient, by utilizing such waste sawdust into useful products. On the other hand, along with the development of technology, the need for plastics continue to increase as a consequence, increased waste plastikpun inevitable. Waste plastic is a material that can not be decomposed by microorganisms decomposing (non-biodegradable), so penumpukkannya in nature feared to cause environmental problems.
INTRODUCTION
Due to the unique nature and characteristics, wood is the material most widely used for construction purposes. The ever-increasing demand for wood and forest potential of dwindling demand the use of wood in an efficient and expedient, by utilizing such waste sawdust into useful products. On the other hand, along with the development of technology, the need for plastics continue to increase as a consequence, increased waste plastikpun inevitable. Waste plastic is a material that can not be decomposed by microorganisms decomposing (non-biodegradable), so penumpukkannya in nature feared to cause environmental problems.
Technological developments, particularly in the field of composite
board, has produced a composite product which is a combination of
sawdust with recycled plastic. The technology was developed in the early
1990s in Japan and the United States. With this technology it is
possible utilization of sawdust and recycled plastic to the maximum,
thus will reduce the amount of waste generated. In Indonesia, research
on these products is limited, whereas raw material waste potential is
enormous.
This paper will present a brief overview of the potential and
utilization of wood waste, particularly sawdust, and plastic waste as a
product of wood-plastic composite powder recycling.
POTENTIAL AND UTILIZATION OF WASTE WOOD POWDER
Human need for wood as building material for the purposes of construction, decoration, and furniture continues to increase along with the increase in population. Timber demand for the timber industry in Indonesia is estimated at 70 million m3 per year with an average of 14.2% per year while roundwood production estimated at 25 million m3 per year, so there was a deficit of 45 million m3 (Priyono, 2001). This suggests that the actual carrying capacity of the forest has been unable to meet the demand for wood. This situation is exacerbated by the presence komversi natural forests into agricultural land, shifting cultivation, forest fires, harvesting practices are not efisen and infrastructure development, followed by forest encroachment. These conditions require the use of wood in an efficient and prudent, among others, through the concept of the whole tree utilization, while increasing the use of non-wood berlignoselulosa, and the development of innovative products as a substitute for wood building materials.
Human need for wood as building material for the purposes of construction, decoration, and furniture continues to increase along with the increase in population. Timber demand for the timber industry in Indonesia is estimated at 70 million m3 per year with an average of 14.2% per year while roundwood production estimated at 25 million m3 per year, so there was a deficit of 45 million m3 (Priyono, 2001). This suggests that the actual carrying capacity of the forest has been unable to meet the demand for wood. This situation is exacerbated by the presence komversi natural forests into agricultural land, shifting cultivation, forest fires, harvesting practices are not efisen and infrastructure development, followed by forest encroachment. These conditions require the use of wood in an efficient and prudent, among others, through the concept of the whole tree utilization, while increasing the use of non-wood berlignoselulosa, and the development of innovative products as a substitute for wood building materials.
Regrettably, to date harvesting and processing of timber in Indonesia
still produces large amounts of waste. Purwanto et al, (1994) stated
the composition of waste in harvesting and wood processing industry are
as follows:
1. On timber harvesting, waste generally shaped logs, reaching 66.16%
2. In industrial sawmill wood waste sawdust covering 10.6 &.
Sebetan 25.9% and 14.3% cuts, a total waste 50.8% of the total raw
material digubakan
3. Industrial waste at the waste pieces of plywood covering 5.6%,
0.7% sawdust, 24.8% wet veneer waste, dry waste veneer peeling the
remaining 12.6% 11.0% and a piece of plywood edges 6.3% . Total waste
plywood for 61.0% of total raw materials used.
Data from the Ministry of Forestry and Plantations in 1999/2000
showed that Indonesia’s plywood production reached 4.61 million m3 of
sawn timber while achieving 2.06 million m3. Assuming the waste
generated is estimated to reach 61% of the wood waste generated reached
more than 5 million m3 (CBS, 2000).
Wood waste in the form of pieces of logs and sebetan been used as the
core block board and particle board material. The waste floured kergaji
utilization is still not optimal. For large, integrated industrial,
waste sawdust sawn been utilized as a form of charcoal briquettes and
activated charcoal are sold commercially. But for the sawmilling
industry small-scale industries, which accounted for thousands of units
and the countryside, the waste has not been used optimally. An example
is the industrial mills in Jambi, amounting to 150 pieces of which are
located on the edge of the river Batang, sawn wood waste generated is
dumped into the river, causing siltation and reduction process stream
segment (Pari, 2002). In most of the wood processing industry waste
sawdust are commonly used as furnace fuel, or burned away without
meaningful use, which can cause environmental pollution (Febrianto,
1999). In order to efficient use of wood are needed to use sawdust into a
more useful product.
FROM PLASTIC TO PLASTIC WASTE RECYCLING
Plastic name representing thousands of different physical properties of materials, mechanical, and chemical. Broadly speaking, the plastic can be classified into two major categories, namely plastics are thermoplastic and thermoset that is. Thermoplastic can be reshaped easily and processed into other forms, whereas when it has hardened types of thermosets can not be softened again. The most common plastic used in everyday life in the form of thermoplastic.
Plastic name representing thousands of different physical properties of materials, mechanical, and chemical. Broadly speaking, the plastic can be classified into two major categories, namely plastics are thermoplastic and thermoset that is. Thermoplastic can be reshaped easily and processed into other forms, whereas when it has hardened types of thermosets can not be softened again. The most common plastic used in everyday life in the form of thermoplastic.
Along with the development of technology, the need for plastic
continues to increase. BPS data in 1999 showed that the volume of trade
of Indonesia’s imports of plastic, especially polypropylene (PP) in 1995
amounted to 136,122.7 tons, while in 1999 amounted to 182,523.6 tons,
so that in this period there was an increase of 34.15%. The number is
expected to continue to increase in subsequent years. As a consequence,
an increase in waste plastikpun inevitable. According to Hartono (1998)
the composition of the waste or plastic waste dumped by each household
was 9.3% of total household waste. In Jabotabek average each plant
produces one ton of plastic waste every week. That number will continue
to grow, due to the properties owned plastics, among others, can not
rot, do not decompose naturally, it can not absorb water, and can not
rust, and eventually ended up being a problem for the environment. (YBP,
1986).
Utilization of waste plastics is an effort to suppress plastic waste
to a minimum and within certain limits save resources and reduce
dependence on imported raw materials. Utilization of waste plastics can
be done with reuse (reuse) and recycling (recycle). In Indonesia, the
use of plastic waste in the scale of general household usage is back
with different purposes, for example, place a plastic paint used for pot
or bucket. Reuse ugly side, particularly in the form of packaging is
often used for product counterfeiting as it often happens in the big
cities (Syafitrie, 2001).
Utilization of waste plastics for recycling is generally done by the
industry. Generally, there are four requirements for a plastic waste can
be processed by an industry, among others, certain wastes must be in
the form as needed (seed, pellets, powder, pieces), the waste must be
homogeneous, uncontaminated, and sought not oxidized. To overcome these
problems, before use of plastic waste is processed through a simple
step, the separation, cutting, washing, and removal of substances such
as iron, and so on (Sasse et al., 1995).
There are things that benefit in the use of plastic waste in
Indonesia compared to developed countries. This is possible because
manual separation is considered not possible in developed countries, can
be done in Indonesia, which has abundant labor so that the separation
does not need to be done with advanced equipment that require high
costs. These conditions allow the development of plastics recycling
industry in Indonesia (Syafitrie, 2001).
Use of recycled plastic in the manufacture of plastic goods back has
been growing rapidly. Almost all types of plastic waste (80%) can be
processed back into the original item must be done despite mixing with
new raw materials and additives to improve the quality (Syafitrie,
2001). According to Hartono (1998) four types of plastic waste are
popular and sell well in the market, namely polyethylene (PE), High
Density Polyethylene (HDPE), polypropylene (PP), and asoi.
UTILIZATION OF WASTE WOOD AND POWDER WOOD PLASTIC COMPOSITES AS PLASTIC RECYCLING
Composite wood is a term used to describe any product that is made from sheets or small pieces of wood glued together (Maloney, 1996). Referring to the definition above, composite wood powder composite plastic is made of plastic as a matrix and wood powder as filler (filler), which has properties of both. The addition of filler into the matrix aims to reduce density, increase stiffness and reduce the cost per unit volume. In terms of wood, with the polymer matrix inside the strength and physical properties will also increase (Febrianto, 1999).
Composite wood is a term used to describe any product that is made from sheets or small pieces of wood glued together (Maloney, 1996). Referring to the definition above, composite wood powder composite plastic is made of plastic as a matrix and wood powder as filler (filler), which has properties of both. The addition of filler into the matrix aims to reduce density, increase stiffness and reduce the cost per unit volume. In terms of wood, with the polymer matrix inside the strength and physical properties will also increase (Febrianto, 1999).
Composite manufacturing using a matrix of plastic that has been
recycled, in addition to improving the efficiency of wood utilization,
can also reduce the load on plastic waste in addition to producing
innovative products as a substitute for wood building materials. The
advantages of this product include: cheaper production costs, abundant
raw materials, flexible in the manufacturing process, low density, it is
biodegradable (rather than plastic), possesses properties better than
the original raw material, can be applied for various purposes, as well
as can be recycled (recycleable). Some examples of the use of this
product are as interior parts of vehicles (cars, trains, airplanes),
furniture, or building components (windows, doors, walls, floors and
bridges) (Febrianto, 1999: Youngquist, 1995).
Wood powder as Filler
Wood powder as Filler
Filler is added to the matrix in order to improve the mechanical
properties of plastics through the deployment of effective stress
between the fiber and the matrix (Han, 1990). Besides the addition of
filler to reduce costs as well as improve some properties of its
products.
Inorganic materials such as calcium carbonate, talc, mica, and
fiberglass is the material most commonly used as a filler in the
plastics industry. The addition of calcium carbonate, mica and talc may
increase the strength of the plastic, but the weight of the product is
also increased so that the transportation costs would be higher. In
addition, calcium carbonate and talc are abrasive to equipment used,
thereby shortening the service life. The addition of fiberglass to
increase the strength of the product but the price is very expensive.
Therefore the use of organic materials, such as wood filler in the
plastics industry began to receive attention. In Indonesia, the
potential for very large timber as a filler, especially the utilization
of waste sawdust is still not optimal.
According Strak and Berger (1997), sawdust has advantages as a filler
when compared to filler minerals such as mica, calcium carbonate, and
talc are: process temperature is lower (less than 400 º F) thereby
reducing energy costs, can be degraded naturally, weight species are
much lower, so the cheaper the cost per volume, low geseknya style so
not to damage equipment on the manufacturing process, and comes from
renewable sources
Some factors to consider in the use of sawdust as a filler in the
manufacture of wood plastic composite is a type of wood, the size ratio
between powder and sawdust and plastic. Another thing to consider is the
nature of wood dust itself. Wood is a material composed mostly of
cellulose (40-50%), hemicellulose (20-30%), lignin (20-30%), and small
amounts of inorganic materials and extractive. Therefore hydrophilic
wood, rigid, and can be biologically degraded. The properties of the
wood causes less suitable when combined with plastic, because it is in
the manufacture of wood-plastic composites required assistance coupling
agent (Febrianto, 1999).
Plastic Recycling In The Matrix
Plastic Recycling In The Matrix
In Indonesia, most of the recycled plastic used again as the original
product with lower quality. Use of recycled plastic as a construction
material is still very rare. In the 1980s, the UK and Italy have been
recycled plastic used to make telephone poles instead of wooden poles or
iron. In Sweden recycled plastic used to manufacture the plastic brick
multistory buildings, because lighter and more powerful than common
brick (YBP, 1986).
Use of recycled plastic in the field of composite wood in Indonesia
is still limited at the research stage. There are two strategies in the
manufacture of wood composites by using plastic, plastic first used as a
binder, while the wood as the main component, the second used wood
filler / filler and a plastic matrix. Research on the use of recycled
polypropylene plastic as a substitute for thermoset adhesives in the
manufacture of particle board made by Febrianto et al (2001). Particle
board product produced has dimensional stability and high mechanical
strength compared to conventional particle boards. Research recycled
plastic as wood plastic composite matrix made Setyawati (2003) and
Sulaeman (2003) by using recycled polypropylene plastic. In the
manufacture of wood plastic composite recycling, some thermoplastic
polymers can be used as a matrix, but is limited by low temperature
decomposition beginning and heating wood (approximately 200 ° C).
Making Process
Basically composite manufacturing recycled plastic wood powder not
unlike the plastic matrix composites with pure. These composites can be
made through the process one stage, two-stage process, and the
continuous process. At one stage of the process, all the raw materials
mixed first manually and then entered into the tool pengadon (kneader)
and processed to produce a composite product. In the two-stage process
of modified plastic raw materials first, then filler mixed together in
the kneader and formed into a composite. The combination of these stages
is known as a continuous process. In this process the raw materials
incorporated gradually and sequentially in a kneader and then processed
through a composite product (Han and Shiraishi, 1990). Generally a
two-stage process produces a better product than the one stage, but the
process takes one step shorter.
Diagram of basic manufacturing process is presented in Figure 1.
Diagram of basic manufacturing process is presented in Figure 1.
Preparation of filler
In principle the preparation of filler intended to get sawdust or wood flour size and uniform moisture content. The more fine powders greater the contact surface between the matriknya filler, so the products become more homogeneous. However, if the terms of decorative composite powder size larger will produce a better appearance because the distribution of the powder timber provides its own value.
In principle the preparation of filler intended to get sawdust or wood flour size and uniform moisture content. The more fine powders greater the contact surface between the matriknya filler, so the products become more homogeneous. However, if the terms of decorative composite powder size larger will produce a better appearance because the distribution of the powder timber provides its own value.
Preparation of Recycled Plastic
Waste plastics are grouped according to the
type of plastic (polypropylene (PP), polyethylene (PE), and so on).
Once cleaned, the waste is chopped to reduce the size, then heated to
its melting point, then processed to form a pellet. Before being used as
a composite matrix made analysts differential thermal (DTA). In the
two-stage process, the pellets diblending first by serving as a coupling
agent in the manufacture of composite compatibilizer.
Blending (Pengadonan)
Blending (Pengadonan)
The stages in this pengadonan adapted to the process used, one stage,
two-stage, or continuous. According to Han (1990) pengadonan conditions
are most influential in the manufacture of composites is the
temperature, rotation rate, and time pengadonan.
The formation of composite
The formation of composite
After the mixing is complete, the sample is directly incurred to
molded into sheets with heat presses. Compression performed for 2.5 – 3
minutes with a pressure of 100 kgf/cm2 for 30 seconds at a temperature
of 170 º C – 190 º C. After cold compression at the same pressure for 30
seconds, the sheet is then cooled at room temperature.
Testing of Composites
Testing of Composites
Composite testing conducted to determine whether the product meets
the requirements specified for a particular use. Type adapted to the
needs of testing, testing fterhadap generally includes physical
properties, mechanical, and thermal composites.
Composite of high quality can only be achieved if the sawdust is well
distributed in the matrix. In fact, the affinity of wood with a plastic
powder is very low because the wood is hydrophilic, while the plastic
is hydrophobic. As a result, the composite is formed has a drainage
properties and low moldability and in turn can reduce the strength of
materials (Han, 1990).
The results of research
The results of research
Studies that have been and are being conducted aiming to produce wood
plastic composite with the best properties. Han (1990), Stark and
Berger (1997), and Oksman and Clemons (1997), examines the factors that
play an important role in the manufacture of wood plastic composite
powder, the type and form of raw material, wood species, the ratio of
filler to the matrix, type and compatibilizer levels, as well as the
conditions at the time of pengadonan. The results show that to some
extent an increase in strength of the composite with the smaller size of
the powder used, as well as the type, ratio of sawdust and plastic, as
well as the type of wood moisture content significantly affect the
properties of the resulting composites. The addition of compatibilizer
to a certain extent affect both the strength of the composite.
Research on wood plastic composite mostly still use plastic purely as
a matrix. Research using recycled matrix, performed by Setyawati
(2003), Sulaeman (2003) by using recycled polypropylene. The results of
the study are summarized as follows:
Setyawati (2003) examined the effect of the size ratio of sawdust to
the matrix and compatibilizer content on physical and mechanical
properties of polypropylene wood composite recycling. The results showed
a similar pattern with a composite that uses pure polypropylene, the
properties of the composites increased with increasing particle size and
smoothness. Sawdust ratio of 50:50 with a matrix with the addition of
2.5% MAH as compatibilizer is accompanied by the addition of initiator
produces optimal composite force, as well as physical properties
sufficient.
Sulaeman (2003), examined the deterioration of wood plastic composite
recycled polypropylene by weather and termites. The results showed a
composite of recycled plastic lumber can be degraded by weather, but
resistant to termite attack.
Research The Moderate / Will Do
Research and testing of wood plastic composite so far has been in the
form of thin sheets, so the test is still based on testing plastics.
Currently Sutrisno (personal communication) is conducting research on
the properties of recycled wood plastic composite in the form of small
clear specimen so testing is directed to the possible use of composites
instead of wood.
Future studies will lead to the determination of the wood plastic
composite board manufacturing the best and the quality of composite
board with pre-treatment on the filler, the selection of modifier /
compatibilizer, the initiator, the determination of process variables,
and the use of materials other than wood berlignoselulosa (research
plan)
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