Recycling of Waste Plastic Materials for the Production of Ceiling Tiles Using Sawdust Reinforcement
Chapter One
Objectives of Study
The objectives of the study are:
- To suggest a method for recycling plastics mixed with sawdust reinforcement for the production of plastic ceiling tiles.
- To determine the effect of particle size of reinforcement on the strength properties of materials.
- To determine the variation of strength properties within each material.
- To compare the Engineering properties of the recycled product to that of the existing tiles.
CHAPTER TWO:
LITERATURE REVIEW
DEFINITION OF RECYCLING
Recycling is the process of separating, collecting and remanufacturing or converting used or waste products into new materials. It also involves a series of activities that include: the collection and sorting of waste materials, the processing of these materials to produce brand new products, and the purchase and use of these new products by consumers. Recycling helps extend the life and usefulness of products that has already served their initial purpose. It is more optimized and efficient if we practice the three R’s of waste management: reduce, reuse, and recycle (Arms, 2010).
Reducing waste that otherwise gets carted off to the recycling centers or landfills is achieved through an intentional decrease in our purchases and consumption, composting of organic waste, and flat refusal to use disposable items like polystyrene and plastic bags. Reusing materials serve to lengthen a particular item’s image. Example of this core: repurposing glass bottles into artistic lamp shades, giving your old cell phones to family or friends for reuse, and up cycling street trash bins into community swimming tubs. Recycling has a lot of benefits and importance not only to humans, but our community and environment but also to our planet.
HISTORY/ORIGIN OF RECYCLING
Recycling
Recycling has been a common practice for most of human history, with recorded advocates as far back as Plato in 400BC. During periods when resources were scarce, archaeological studies of ancient waste dumps show less household waste (such as ash, broken tools and pottery) implying more waste were recycled in the absence of new material (Black Dog publishing, 2006).9
In pre-industrial times, there was evidence of scrap bronze and other metals being collected in Europe and melted down for perpetual reuse (The Economist, 2007). In Britain, dust and ash from wood and coal fires were collected by ‘dustmen’ and downcycled as a base material usedn in brick making. The main drivers for these type of recycling was the economic advantage of obtaining recycled feedstock instead of acquiring virgin materials, as well as a lack of public waste removal in ever more densely populated areas. In 1813, Benjamin Law developed the process of turning rags into ‘shoddy’ and ‘mungo’ wool in Batley, Yorkshire. This material combine recycled fibres with virgin wool. The West Yorkshire shoddy industry in towns such as Batley and Dewsbury lasted from the early 19th century to at least 1914.
Industrialization spurred demand for affordable materials, aside from rage, ferrous scrap metals were coveted as they were cheaper to acquire than was virgin ore. Railroads both purchased and sold scrap metal in the 19th century, and the growing steel and automobile industries purchased scrap in the early 20th century. Many secondary goods were collected, processed, and sold by peddles who combed dumps, city street and went door to door working for discarded machine parts, pots, pans, and other sources of metal. By World War I, thousands of such peddlers\ roamed the streets of American cities, taking advantage of the market forces to recycle post consumer material back into industrial production (Zimiring, 2005).
Beverage bottles were recycled with a refundable deposit at some drink manufactures in Great Britain and Ireland around 1800, notably Schweppes (Shire, 2012). An official recycling system with refundable deposits was established in Sweden for bottles in 1884 and aluminum beverage cans in 1982. Laws leading to a recycling rate for beverage containers of 84-99 percent depending on type, and average use of a glass bottle are over 20 refills. Resource shortage caused by the world wars, and world-changing occurrences greatly encourages recycling. Massive government promotion campaigns were carried out during World War II in every country involved in the war, urging citizens to donate metals and conserve fibre, as a matter of significant patriotic importance. For example, in 1939, Britain launched the programme paper salvage to encourage the recycling of materials to aid the war effort. Resource conservation programs established during the war were continued in some countries without abundant natural resources, such as Japan, after the war ended.
The next big investment in recycling occurred in the 1970s, due to rising energy costs. Recycling of aluminum used only 5% of the energy required by virgin production, glass, paper and metals have less demand but very significant energy savings when recycled feedstock was used (The Economist, 2007).
Overview of Plastics
Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. Plastics are derived from petroleum or natural gas. Hydrocarbon molecules or monomers are chemically bonded into chains called polymers or plastic resins. A variety of manufacturing techniques and combinations of monomers result in plastic resins that have distinct characteristics which make various plastics suitable for different applications. There are thousands of plastics with various properties that lend specific resins to differing applications. Plastics are mouldable, stretchable and meltable. Some have memory, like bottles that pop back to their original shape. Others prevent gas exchange, keeping carbonation in soda. Some plastics have chemical resistance and safely contain household cleaners. Some, like tub lids, are flexible and can be handled repeatedly without breaking.
There are two categories of plastic resins:
- thermoplastic resins which can be repeatedly softened with heat and remoulded without a significant reduction in performance; and
- thermoset resins which when remelted undergo decomposition.
CHAPTER THREE
EXPERIMENTAL METHODS AND MATERIALS
EXPERIMENTAL APPARATUS
The experimental apparatus for the ceiling tile production consists of the following:69
(1) Box furnace
(2) Metal crucibles
(3) Metal moulds
(4) Sieve shaker
(5) Sieve
(6) Weighing balance
(7) Metal tongue
SOURCE OF SAMPLES
The “sachet water” polyethene plastic waste popularly known as “pure water sachet” were initially collected from different waste dumps in Nsukka town but due to the difficulty of sourcing for the waste from waste dump sites, it was discovered that large quantity can be obtained from Lion table water, University of Nigeria Nsukka and Assurance table water, Ogurugu road Nsukka respectively at their waste dump. The sawdust was gotten from the wood saw mill at Nsukka Timber Processing Company. The waste dumps of these table water companies were located within the company compounds which they usually evacuate each day to different landfills. The table water bottles were generated by the above table water companies during their production processes. Other plastic containers were sourced from different homes; waste dumps and greater percentage were bought from plastic dealers at Ogige market in Nsukka, and include some of the damaged product from their warehouse.
RATE OF GENERATION OF WASTE PLASTIC MATERIALS
The collection of the waste plastic materials used in this research work was done during the intense rainy season. During the collection process, I attempted to determine the rate at which Lion Table water, University of Nigeria, Nsukka generated sachet water waste on weekly basis.
These are wastes which were generated during sachet water production via machine rejection or 70 mistake encountered during production excluding the ones that would have been generated by the customers; I was surprised to discover that an average of four weeks was about 1.2kg of waste was generated. Considering this rate of generation, one would imagine how much this waste would amount as we know that dry season in Nigeria results to great demand for portablen water because of the high heat caused by constant sunshine and dryness of the weather.
MATERIAL PREPARATION
Sample Preparation for Plastic Materials
The polythene materials when collected from the waste dump are wet and dirty but it was washed, shredded and then spread under the sun to dry and make it ready for recycling process. The dried samples of the polyethene materials were then collected in a crucible which was placed in the hot heat of the box furnace for pre-melt. This process was repeated for the water bottles and other plastics respectively. During the pre-melting process, the plastic materials were pre-heated in the furnace and allowed to form together. It was then divided into smaller pieces while it was still hot and then allowed to cool and solidify. They were then weighed into samples of equal weight (i.e. 800g) in readiness for the main experiment. Twenty six samples were prepared for the experiment.
CHAPTER FOUR
RESULTS AND DISCUSSIONS
Two tests were conducted on the materials were the tensile strength and the hardness test. The test samples were 28 in numbers, 25 of them were reinforced, one was without reinforcement, and then the remaining two were existing tiles, local and foreign tiles respectively.
PRESENTATION OF RESULTS
The experimental results are presented graphically in Figures 4.1 – 4.16. Figures 4.1 – 4.5 depicted tensile strength results of materials prepared with different quantities of sawdust but the same particle sizes. Figure 4.6 shows the frequency of different proportions of sieve sizes that gave the maximum strength. Figures 4.70 – 4.11 showed the tensile strength results of the plastic tile material with the different particle sizes of sawdust but the same weights. Figure 4.12 gives the analysis of the sieve size that are the maximum stress, then Figure 4.13 shows the tensile strength results of sample prepared without any sawdust reinforcement, Figures 4.14 – 4.15 show the result of the hardness survey test carried out on all the materials including two existing tiles, foreign and local respectively, and finally Figure 4.16 shows the comparison between some selected materials and existing foreign and local tiles respectively.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
CONCLUSION
Experimental investigations were carried out on various recycled plastic waste materials such as sachet water polyethene, plastic table water bottles and other plastics. This ended up limiting the research to recycling of sachet water waste plastic; by experiment conducted using sawdust reinforcement for different particle sizes and weights. The following conclusions were drawn from the study as follows:
- Plastic wastes constitute environmental problems, but can be recycled to make different products one of which is Plastic ceiling tile which is a Civil Engineering material.
- Plastic waste materials when reinforced with sawdust during recycling produce hard and quality material.
- From the hardness test conducted it was concluded that the strengths were not uniformly distributed along the whole area of the board possibly because of poor laboratory process as a result of lack of proper recycling equipment.
- That through proper recycling process, the recycled products can match the qualities and properties of the some imported ones.
- When Plastics are recycled, raw materials for the production of virgin products like petroleum and other energy sources will be conserved.120
RECOMMENDATIONS
Based on the findings of this research work, it is recommended that:
- Further studies should be carried out on this subject using other reinforcements, quality recycling equipment and process to achieve the best result.
- There should be adequate machinery for testing the quality and Engineering properties of the materials produced so that any product send to the markets will encourage the consumers to buy recycled goods.
- Recycling should be well structured and funded to save our environment from the menace of solid waste especially plastic waste.
- For proper management and disposal of wastes, there should be encouraging government policy both on manufacturers and consumers and financial penalty for defaulters.
- A sound market should be developed for the marketing of proceeds from recycling and there should be incentives for recycling workers who has done well.121
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