Effects of Weathering on some Mechanical Properties of Blends of Recycled Polypropylene with Polystyrene, Polyvinyl Chloride and Virgin Polypropylene.
ABSTRACTS
Natural weathering of the blends of recycled polypropylene (PPr) with (PS), Polyvinyl chloride (PVC) and Virgin Polypropylene (PPv) was studied.
Film of 25 by 1.5 by 0.02Cm3.PS, PVC and PPv were blended with PPr for the of improving its mechanical properties, which was generally considered as inferior.
While no particular blends had over all good result of all the mechanical tested, however, PS/PPr produced the best result of tensile strength, followed by the blends of PPv/PPr and PVC/PPr.
The blend of PPv/PPr had the highest elongation followed by the blends of PVC and PS. The young modulus results show that at 20%, the PS blends has the highest young modulus.
Also PS blend resist embrittlement more than PPv and PVC blends. In summary the blends of PS and PPr at ratio 20:80 is considered good enough to improve the mechanical properties of recycled polypropylene better than the other blends.
TABLE OF CONTENTS
TITLE PAGE I
DECLARATION II
CERTIFICATION III
DEDICATION IV
ACKNOWLEDGEMENT V
ABSTRACT VI
TABLE OF CONTENTS VII
LIST OF TABLES X
LIST OF SCHEMES XI
LIST OF PLATES XII
LIST OF FIGURES XII
CHAPTER ONE
INTRODUCTION
1.1 Introduction 1
1.2 Aim of the research 3
CHAPTER TWO LITERATURE REVIEW
2.1 Polypropylene; a brief history 4
2.2 Polystyrene; a brief history 6
2.2.1 Structure of Polystyrene 6
2.2.2 Polymerisation of Polystyrene 7
2.3 polyvinyl chloride; a brief history 7
2.3.1 Polymerisation 9
2.4 Polymer weathering 9
2.41 Mechanical properties of polymer 10
2.4.2 Polymer blending 11
2.4.3 Process of u.v degradation in polymers 12
2.4.4 Chain Scission and Cross linking 13
2.4.5 Molecular Mass Reduction 13
2.4.6 Photo oxidation; a free radical chain mechanism 14
2.4.7 Photodegradation Chemical reaction process in polypropylene 15
CHAPTER THREE MATERIALS AND METHODS
3.1 Introduction 18
3.2 Material acquisition and preparation 18
3.2.1 Materials and Methods 18
3.2.2 Preparation 18
3.3 Formulations 19
3.4 Productions of films 21
3.4.1 Environmental Exposure 22
3.4.2 Method of Monitoring Degradation 23
3.4.3 Embrittlement Time 23
3.4.4 Tensile tests 24
CHAPTER FOUR RESULTS AND DISCUSSION
4.1 Tensile strength 25
4.2 Breaking elongation 33
4.3 Young modulus 40
4.4 Embrittlement 47
CHAPTER FIVE SUMMARY AND CONCLUSION
5.1 Summary and conclusion 50
REFERENCES 51
APPENDIX 53
INTRODUCTION
Plastics; materials made up of large organic (carbon – containing) molecules that can be formed into a variety of products.
The molecules that compose of plastics are long carbon chain that gives plastics many of their useful properties. In general, material that is made up of long chain like molecules are called polymer.
Plastics are indispensable to our modern way of life. Plastics are used in low performance products like toys, wrapping product, storage of beverages and also high performance products like automobile, aerospace, constructions, packaging and electrical industries.
Plastics are also used in specialized fluids, such as the health industries to make medical instruments, dental fillers, optical lenses and bio compatible joints.
Plastic materials have substituted ferrous, wood and ceramic materials in many applications, for this reason, plastic consumptions have increased exponentially in the past decade.
Infact, the demand for plastic products and goods is on the increase due to rapid population growth and changes in consumption pattern, particularly for packaging; shopping, carrier bags, containers, agricultural tools, water satchet and house hold items.
There are environmental problems and challenges associated with the management of plastic wastes in Nigeria as well as in many developing countries.
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Akay, G., Tincer T and Ergoz, H.E (1980). Polymer Photodegradation: Mechanism and Experimental Methods .European Polymer Journal, PP. 601- 605.
Ashby, M. (1996). Engineering Materials (2nd edition) Butterworth, Heinemann, PP191-195.