ABSTRACT
In this study, Jute fibre/ Unsaturated Polyester Resin and Maize Cob / Unsaturated Polyester Resin Composites were prepared. Similarly, hybrid composites of Jute fibre (JF)/Maize Cob(MC) with Unsaturated Polyester Resin(UPR) were prepared using an open molding techniques at several percentage filler loadings, 10% Maize Cob and 10% Jute fibres were employed as the percentage for composites hybridization. The Physical and Mechanical properties of the composites were studied. The Scanning Electron Microscopy of the composites was also investigated. The study reveals that, as the percentage filler loading increases, the tensile strength, elongation, impact strength, hardness and flexural strength decreases due to clumping, voids and agglomerate formation which resulted in weak bonding or poor inter facial adhesion between the fillers and the matrix. However, the hybrid composite shows moderates improvement in the mechanical properties such as tensile strength of 32.86 Mpa and elongation of 19.60 % for 5%JF/5%MC which has the highest strength compared to its control samples which has tensile strength of 12.84Mpa and elongation at break of 12.80% for 10%JF/UPR and 21.55Mpa and 16.00% for 10% MC/UPR respectively. The hybrid composite also shows moderate value of impact strength, hardness and flexural strength with 0.48J/m, 37.65 shore A and 44.79Mpa respectively for filler loading of 5%JF/5%MC and 0.35 J/m,21.17 shore A and 41.47Mpa for varying fillers of 9%JF/1%MC hybrid composite sample. The improvements are likely attributed to the extent of good intermingling between the fillers and the matrix. The study also reveals that, density of the composites decreases with increase in filler loading the density drops from 1.66 to 0.80g/cm3 for 100%UPR and 15% JF/UPR composites respectively and from 1.66 to 0.70g/cm3 for 100% UPR and 20% MC/UPR composites respectively. The hybrid composite also shows decrease in density from 1.29 to 1.00g/cm3 with varying percentage of filler loadings of 9%JF/1%MC and 7%JF/3%MC respectively. The composites shows increase in water uptake with increasing filler loading and increasing number of days up to when the samples reaches their saturation when no water absorption was observed. The results shows that the highest water absorption rate was observed at 15% filler loading of JF having maximum water absorption of 6.4% and 3% for 20% MC and a maximum of 2.3% for hybrid composites. SEM analysis shows good interfacial interaction between the fillers and the matrix, random filler dispersion within the matrix and formation of few noticeable voids which could be due to air trapped during the composites fabrication and cracks along filler matrix interface which has effect in the mechanical properties of the composites samples. The mechanical and physical properties of the composites indicate that it can be useful in application which required moderate strength. These composites could be considered as a potential source of utilizing agricultural waste materials and as sustainable resources for manufacturing of structural materials such as particle board, fibre board, stores and library shelf‘s, partitioning panels, ceiling boards thereby reducing the amount of agricultural wastes and eliminating the pollution caused by burning of such residue (Maize Cob) and in turns adding value to Jute fibre.
TABLE OF CONTENTS
Cover page ……………………………………………………………………………………..i Title page……………………………………………………………………………………….ii Declaration page………………………………………………………………………………..iii Certification page………………………………………………………………………………….iv Acknowledgement………………………………………………………………………… ……v Abstract………………………………………………………………………………………….vi Table of Content……………………………………………………………………………….viii List of figures……………………………………………………………………………………xii List of tables…………………………………………………………………………………. …xiii List of plates……………………………………………………………………………………..xiv
Abbreviations………………………………………………………………………………. ……xv
CHAPTER ONE …………………………………………………………………………………………………………….. 1
1.1 Introduction…………………………………………………………………………………1
1.2 Statement Of The Research Problem. ………………………………………………………………………. 3
1.3 Aim And Objectives Of The Research …………………………………………………………………….. 3
1.3.1 Aim …………………………………………………………………………………………………………………….. 3
1.3.2 Objectives Of The Research ……………………………………………………………………………………. 4
1.4 Justification ………………………………………………………………………………………………………….. 4
1.5 Scope Of The Study ………………………………………………………………………………………………. 4
CHAPTER TWO ……………………………………………………………………………………………………………. 5
2.0 Literature Review……………………………………………………………………………………………………… 5
2.1 Fibre ………………………………………………………………………………………………………………….. 5
2.1.1 Natural Fibres ……………………………………………………………………………………………………. 5
2.1.2 Man-Made Fibres ………………………………………………………………………………………………. 6
2.1.3 Mineral Fibres. ………………………………………………………………………………………………….. 6
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2.2 Jute Fibre ……………………………………………………………………………………………………………… 6
2.2.1 Jute Cultivation ……………………………………………………………………………………………….. 7
2.2.2 Harvesting.. ………………………………………………………………………………………………………. 8
2.2.3 Retting ……………………………………………………………………………………………………………… 8
2.2.4 Water Retting ………………………………………………………………………………………………… 10
2.2.5 Natural Water Retting: ……………………………………………………………………………………… 10
2.2.6 Tank Water Retting ………………………………………………………………………………………….. 10
2.2.7 Mechanical Reting…………………………………………………………..………….11
2.2.8 Chemical Retting ……………………………………………………………………………………………… 11
2.2.9 Enzymatic Retting ……………………………………………………………………………………………. 11
2.2.10 Stripping (Fibre Extraction) ………………………………………………………………………………. 12
2.2.11Washing And Drying …………………………………………………………………………………………… 12
2.2.12 Chemical Compositions Of Jute…………………………………………………………………………..12
2.2.13 Uses Of Jute ……………………………………………………………………………………………………. 13
2.3 Maize…………………………………………………………………………………………………………………. 14
2.3.1 Cultivation ………………………………………………………………………………………………………. 14
2.3.2 Hervesting Of Maize ………………………………………………………………………………………… 16
2.3.3Storage Of Maize …………………………………………………………………………………………………… 16
2.3.4 Characteristics Of Maize …………………………………………………………………………………… 16
2.3.5 Maize Cob ………………………………………………………………………………………………………. 17
2.4 Unsaturated Polyester Resin …………………………………………………………………………….. 17
2.4.1 Gelation, Curing And Post-Curing ……………………………………………………………………. 22
2.5 Composite Material ………………………………………………………………………………………….. 23
2.5.1 Matrix ……………………………………………………………………………………………………………… 24
2.5.2 Reinforcement ………………………………………………………………………………………………….. 25
2.5.3 Characteristics Of Composites Materials ……………………………………………………………. 25
2.5.3 Classification Of Composites …………………………………………………………………………… 26
2.5.4.1 The Basis Of Matrix: …………………………………………………………………………………………. 26
2.5.4.1.1 Metal Matrix Composites (Mmc) …………………………………………………………………… 26
2.5.4.1.2 Ceramic Matrix Composites (Cmc) ………………………………………………………………… 26
2.5.4.1.3 Polymer Matrix Composites (Pmc) ………………………………………………………………… 26
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2.5.4.1.3.1 Thermosets …………………………………………………………………………………………………… 27
2.5.4.1.3.2 Thermoplastics ……………………………………………………………………………………………… 27
2.5.3.4 On The Basis Of Filler Material: ………………………………………………………………………….. 28
2.6 Natural Fibre Reinforced Composites ………………………………………………………………… 28
2.7 Hybrid Composites ………………………………………………………………………………………….. 28
2.7.1 Types Of Hybrid Composites …………………………………………………………………………… 30
2.9 Open Molding ………………………………………………………………………………………………….. 30
2.9.1 Hand Lay-Up Method ……………………………………………………………………………………….. 31
2.10 Testing Of Composites ……………………………………………………………………………………… 31
2.10.1 Mechanical Tests ……………………………………………………………………………………………… 31
2.10.1.1 Tensile Properties…………………………………………………………………………………………… 32
2.10.1.2 Impact Strength …………………………………………………………………………………………….. 34
2.10.1.3 Hardness ………………………………………………………………………………………………………. 34
2.10.1.4 Flexural Strength …………………………………………………………………………………………… 34
2.10.2 PHYSICAL TESTS: ………………………………………………………………………………………… 35
2.10.2.1 Density ……………………………………………………………………………………………………………. 35
2.10.2.2. Water Absorption …………………………………………………………………………………………….. 35
2.11 Scanning Electron Microscopy (SEM) ………………………………………………………………….. 35
CHAPTER THREE ………………………………………………………………………………………………………. 37
3.0 MATERIALS AND METHODS. ……………………………………………………………………….. 37
3.1 Materials……………………………………………………………………………….37
3.2 Equipment: ……………………………………………………………………………………………………….. 37
3.3 Preparation of Maize cob powder ………………………………………………………………………… 38
3.4 Extraction of Jute Fibres …………………………………………………………………………………….. 38
3.5 Unsaturated Polyester Resin ……………………………………………………………………………….. 38
3.6 Composites preparation ……………………………………………………………………………………… 39
3.6.1. Jute Fibre/ Unsaturated Polyester Resin composites ………………………………………………. 39
3.6.2. Maize cob/ Unsaturated Polyester Resin composites ……………………………………………… 39
3.6.3. Preparation of Hybrid Composites (Jute fibres/Maize cob/Unsaturated polyester) …….. 40
3.7 CHARACTERIZATION OF THE COMPOSITES ………………………………………………… 41
3.7.1 MECHANICAL TESTS: …………………………………………………………………………………….. 41
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3.7.1.1 Tensile Strength Test ………………………………………………………………………………………….. 41
3.7.1.2 Impact Strength ………………………………………………………………………………………………….. 42
3.7.1.3 Hardness Test …………………………………………………………………………………………………….. 42
3.7.1.4 Flexural Strength ……………………………………………………………………………………………….. 42
3.7.2 PHYSICAL TESTS: ………………………………………………………………………………………….. 43
3.7.2.1 Water Absorption ……………………………………………………………………………………………… 43
3.7.2.2 Density: …………………………………………………………………………………………………………… 44
3.7.3 Scanning Electron Micrsocopy …………………………………………………………………………… 44
CHAPTER FOUR …………………………………………………………………………………………………………. 46
4.0: RESULTS AND DISCUSSION …………………………………………………………………………… 46
4.1 Mechanical Tests: ………………………………………………………………………………………………. 46
4.1.1 Tensile Strength …………………………………………………………………………………………………. 46
4.1.2 Elongation at Break……………………………………………………………………………………………. 50
4.1.3 Impact Strength Test: …………………………………………………………………………………………. 53
4.1.4 Hardness Test: …………………………………………………………………………………………………… 56
4.1.5 Flexural Test: ……………………………………………………………………………………………………. 59
4.2 PHYSICAL TESTS: ………………………………………………………………………………………….. 62
4.2.1 Density …………………………………………………………………………………………………………….. 62
4.2.2 Water Absorption ………………………………………………………………………………………………. 65
4.3. Scanning Electron Microscopy ……………………………………………………………………………. 69
CHAPTER FIVE ………………………………………………………………………………………………………….. 73
5.0 CONCLUSION AND RECOMMENDATION ………………………………………………………. 73
5.1 Conclusion ………………………………………………………………………………………………………… 73
5.2 RECOMMENDATIONS ……………………………………………………………………………………. 74
REFENCES…………………………………………………………………………………….. 76
CHAPTER ONE
1.0 INTRODUCTION
Interest in the utilization of bio-fillers in thermosetting and thermoplastics has received increasing attention both by the academic sector and the industry. Natural fillers have many significantadvantages over synthetic fillers and fibres, such as their light-weight, low cost, ability to reduce abrasion of machinery and also non-toxicity(Nabi-saheband Jog,1999).In addition,use ofmaize cob and jutefibres as fillers have advantages over mineral fillers, as they are non-abrasive, require less energy for processing and ability to reduce the density of finished products. Hence, natural fibre composites have attracted much attention, and are becoming increasingly important for the production of a wide variety of cheap light-weight environment friendly composites(Bharath,etal.,2014).
Increasing concern about global warming and depleting petroleum reserves have made scientists to focus more on the use of natural fibres such as Jute, bagasse, coir, sisal, etc. Many research articles have been published to justify the utility and to establish advantageous features of such natural fibres.This has resulted in creation of more awareness about the use of natural fibres based materials mainly composites(Madhusudhanaet al.,2014). In past decades there have been many efforts to develop composites to replace the petroleum and other non-decaying materials based products. The abundant availability of natural fibres gives attention on the development of natural fibre composites primarily to explore value-added application avenues. Reinforcement with natural fibre in composites has recently gained attention due to low cost, easy availability, low density, acceptable specific properties, ease of preparation, enhanced energy recovery, Co2 neutrality, biodegradability and recyclable in nature (Vermalet al.,2013). The present research work is more interested in preparing a hybrid composites made of natural
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fibres as they are abundantly available and cheaper compared to synthetic fibres which need to be processed and made-up of chemicals to gain the required property of composites. These natural fibres yield better mechanical strength when added to thermosets or thermoplastics. The mechanical properties of particulate filled polymer composites depend strongly on the particle size, particle-matrix interface adhesion and particle loading (Ishiaku et al.,2007). In the recent years, Polymer matrix composites are gaining more importance compared to monolithical materials as being more reliable and cheaply available. With the advancement of polymer matrix composites (PMC) their properties have been increased by one. The addition of one more fibre as hybrid composites boost the property of PMC. The single fibre composite lags polymeric composite materials in variety of uses such as automotive, sporting goods, marine, electrical, industrial, construction, household applications etc. Polymeric composites have high strength and stiffness, light weight and high corrosion resistance. (Madhusudhana et al.,2014)
Most of the composites available in the market today are produced with a high durability to ensure product longevity. Unfortunately, in order to make these products, companies have traditionally used non-biodegradable fibres, made from non-renewable resources. The most important disadvantage of such composite materials is the problem of disposal after end use. This draw the attention of researchers‘to the use of natural,sustainable,biodegradable and renewable resources. In modern production environment, there is a great demand for every material to be recyclable or degradable. Natural fibres composites, are composite materials i.e., formed by a matrix (resin) and a reinforcement (fibre), in which the fibres are natural i.e., mainly formed by cellulose and therefore originating from plants. Some of these fibres can be hemp, Jute, flax, sisal, banana, kapok etc. Natural fibre composites(NFC) markets are significantly on the rise, mainly because of the environmental necessitiesand recyclability, unsaturated polyester
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is an outstanding commercially important thermosetting material with wide range of applications in various fields because of its balanced chemical and mechanical properties(Navdeep et al,2012) .In this study, maize cob and Jute fibre/unsaturated polyester composites were prepared with Maize cob and Jute fibre as filler and Unsaturated Polyester Resin(UPR) as the matrix.
1.2 STATEMENT OF THE RESEARCH PROBLEM.
Composites of synthetic fillers and matrices are non-biodegradable and help in constituting environmental hazards.On the other hand natural fillers in synthetic matrices produce composites that are biodegradable. In the quest to develop biodegradable composites which are environmental friendly, this research prepared and characterized composites of jute fibre and maize cob as well as hybrid composites of the two fillers with unsaturated polyester resin. It is intended to in addition to development of biodegradable composites, value will beadded to jute fibres and maize cob, especially the maize cob which hitherto has very little popularity in the composites world despites its large abundance that mostly end up as waste.Jute fibres on the other hand are equally grown abundantly and have been used in clothing and composites. Both short fibres and particulates composites have their unique characteristics. It is hoped that by combing jute fibres and maize cob to produce hybrid composites, materials that have the advantages of short fibres as well as particulate properties will be produced in addition to being biodegrable and having low cost.
1.3 AIM AND OBJECTIVES OF THE RESEARCH
1.3.1 AIM To prepare hybrid composites of Jute fibre/ Maize cob particles / Unsaturated Polyester Resin, and evaluate their physical and mechanical properties.
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1.3.2 OBJECTIVES OF THE RESEARCH i. To extract Jute fibre by water retting method. ii. To use Maize cob and Jute fibre as bio fillers at different filler loadings in unsaturated polyester resin to obtain bio composites. iii. To study the physical and mechanical properties,(such as density, tensile strength, impact strength, hardness, flexural strength, and water absorption). iv. To study the effect of different filler loadings on the properties of hybrid composites of Maize cob in particulate form and Jute fibre in short length reinforced in unsaturated polyester resin.
1.4 JUSTIFICATION
Due to the drawbacks associated with using synthetic fibres in composites, this study intends to explore the use of hybrid reinforcement of Jute fibre/Maize cob as a way of improving their properties to make them amenable for use in hybrid composites. The success of this hybrid will reduce the cost of composites as Jute fibre and Maize cob are readily and abundantly available at little or no cost in the country and also reduce environmental waste problem.
1.5 SCOPE OF THE STUDY The scope are as stated below: 1. Only short lengths of Jute fibres (0.5-1cm), is used. 2. Particulates sizeof Maize cob (300μ) employed. 3.Unsaturated Polyester Resinhas been used as a matrix
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