ABSTRACT
Plastic waste remains an environmental menace around the world but more so in Sub-Saharan Africa. In Nigeria, recycling of plastics has been adopted notably for making fencing posts, and this has been an object for job creation. However, there is still a lot that needs to be done, bearing in mind that a lot of plastic waste still litters the environment. A table top Compression moulding machine was designed and modified to complement already existing efforts towards recycling. In addition to the sound environmental management option this provides, it is hoped that the machine could assist in job creation and more so at local individual levels where idle youths can find an economic activity to engage in. Tensile specimens made from Virgin High Density Polyethylene (HDPE) using the machine, were tested for Ultimate Tensile Strength (UTS) which was found to have a value of 13 MPa and Modulus of Elasticity (E) which was found to have a value of 0.9 GPa and the results are comparable to documented values which were 15 MPa and 0.8 GPa respectively. Recycled plastic was then added to the virgin plastic at various contents to obtain an optimum processing point for the machine. These samples at varying contents of recycled plastic were also subjected to tensile and three point bending test. The general observation was that addition of recycled plastic to the virgin plastic improved tensile and shear strength but declined the tensile modulus of elasticity. Addition of steel wires to the plastic at 60% recycled plastic content, improved tensile strength and modulus of elasticity. Compared to other studies, it was observed that the material obtained could be suited for low strength car bumpers. There is still room for further improvement work on this manually operated machine but results obtained so far are promising as the machine can be used to produce small plastic items such as pegs, complete toys or toy parts, beads and other small plastic items.
CHAPTER ONE
INTRODUCTION
• Background of study
The long-term strategic plan for Nigeria, Vision 2030 (G.O.K, 2007), and the Millennium Development Goals (MDG) all seek to eradicate poverty by ensuring that society is engaged in economic activities that are sustainable. Sustainability involves interconnection of ecology, economics, politics and culture. Therefore in order to attain the visions spelt out in the above development blue prints there is need to consider the effect of a potential economic activity on the environment and ensure that it is politically and culturally acceptable.
For example, the plastic manufacturing industry in Nigeria offers employment to many in the population. This is due to the high number of applications that plastics have in our everyday life. However, at the end of their usefulness most of this plastics are dumped haphazardly making this business ecologically unsuitable. This situation can however be changed since most of this waste plastics are High Density Polyethylene (HDPE), which is used for packaging in most supermarkets and shopping stores. HDPE is a thermoplastic and therefore recyclable. If Nigeria embraces recycling of plastics in her culture, this would mean creation of employment and in a way that is friendly to the environment. Recycling efforts have been seen where plastic wastes are turned into fencing posts. However the machines used here are bulky, consume large amounts of electricity, and will need high capital to venture into. There is therefore need to downscale recycling to complement the efforts already in place while also addressing the unemployment issue.
Dumping of waste tyres is another issue of concern in Nigeria. Tyres are made mostly from rubber, with steel wires, fibers and other miscellaneous constituents. Old tyres in Nigeria will be retreaded by local artisans (in Jua Kali cottage industries), a situation that could be responsible for some of the road accidents in Nigeria. Tyres that are can no longer be retreaded are dumped carelessly, or end up being burnt down, a situation that pollutes the environment. The steel wires so generated are left to rust away, resulting in more pollution, or they are sold to scrap metal dealers. This research explores use of this steel wires with recycled plastics as a potential material that could be useful and hence mitigate the waste dumping problem.
• Problem statement
Plastic waste remains a serious environmental menace in most parts of Sub Saharan Africa (Bashir, 2013), although in Nigeria there have been efforts geared towards recycling, where plastic wastes are recycled into fencing posts there is still a lot of plastics littering the environment. Engaging in plastics recycling remains the preserve of individuals who can afford the high initial capital required to buy the big recycling machines, which will also require large room and use of large quantities of electricity making the overall running cost too high for many. And keeping in mind that most of the unemployed people in Nigeria are the youth, there is a felt need to come up with innovations that provide an avenue for self-employment, that do not require a high initial capital investment and overall running cost. According to Nigerian government figures the youth account for over 61% of the unemployed (G. O. K, 2015). Most of this youth are wasting away in drug and alcohol abuse. There is therefore need to provide employment for the youth. The objective of this study is to design a moulding machine that can be used to produce useful products from plastic wastes.
The study goes further and investigates potential inclusion of steel wires from old tyres in recycled plastics, as a potential material for various applications. This is motivated by the fact that old tyres are also dumped in ways that lead to environmental pollution and destruction of aesthetics in the dump site. Some old tyres are also retreaded at the Jua kali sector posing a serious risk of accidents on the roads. Burning of old tyres is known to produce pollutants to air soil and water. Hence, the study explores an application of the steel wires from old tyres that is not detrimental to the environment.
• Significance of study
The advent of plastics for various packaging uses has only served to aggravate what was already a serious waste management crisis in Sub Saharan Africa. Plastic wastes are an environmental menace because they are not biodegradable and it takes many years for these wastes to wear out (Verma, 2009). This research sort to design a machine for plastic recycling made from locally available materials, one that would consume less room and power compared to already existing industrial machines. This would ensure that the machine is affordable to the average Nigerian, and this would create an avenue for employment creation and income generation.
• Scope of study
The work in this study involves design and modification of a thermoplastic compression moulding machine for plastic recycling. To test use of the machine, samples will be made from plastic and later the plastic will be reinforced with steel wires from old tyres. This samples will be subjected to mechanical testing to gauge the strength of the products.
• Objectives of study
Overall objective
The overall objective of this research was to develop a versatile compression moulding machine from locally available materials for plastic recycling.
Specific objectives
The specific objectives are;
• Design and modify a table top compression moulding machine.
• To compare tensile properties of samples made from virgin HDPE using the machine with other documented values.
• To assess the effect of addition of recycled plastic to the mechanical properties of the virgin plastic
• To develop a composite material from the highest recycled plastic content and steel wires from old tires.
• To characterize the mechanical properties of the composite, and asses possible applications for the composite.
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Item Type: Project Material | Size: 46 pages | Chapters: 1-5
Format: MS Word | Delivery: Within 30Mins.
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