ABSTRACT
Nanocrystalline cellulose (NCC) was extracted from corn cob using Acid hydrolysis. Pre-treatments applied to the corn cob before the acid hydrolysis include: grinding to provide more surface area for hydrolysis and subsequent processes, caustic soda treatment (scouring) to remove lignin and other unwanted materials and bleaching to remove the inherent natural yellowing in plant materials. The extracted NCC was characterized using SEM, PSA, FT-IR, XRD and TGA. Other properties investigated are density and swelling index. The extracted NCC was then dyed (alongside fabrics as control) with disperse, reactive, direct and acid dyes. The exhaustion of each of the dyes was investigatedand fixation of the reactive dye also studied. Colour fastness of the dyed NCC to washing, chlorinated water and light were then investigated. The FT-IR results showed that there is successful removal of lignin and hemielluloses. The X-ray diffraction analysis shows successful increase in crystallinity from corn cob (crystallinity index 67.65%) to NCC (crystallinity index 78.90%). The thermogravimetric analysis shows that thermal stability of polymers is directly related to number of units fused together. It also shows that the present of impurities increase thermal stabilities. Satisfactory exhaustions were obtained with both dyes. This shows that, NCC can be dyed with any of the three classes of dyes used. However, the colour fastness results show that the choice of dye depends on the end use of the NCC to be dyed.
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TABLE OF CONTENTS
Title page – – – – – – – – – – i
Declaration – – – – – – – – – – ii
Certification – – – – – – – – – – iii
Acknowledgment – – – – – – – – – iv
Dedication – – – – – – – – – – vi
Abstract – – – – – – – – – – vii
Table of contents – – – – – – – – – viii
List of Tables – – – – – – – – – xiii
List of Figures – – – – – – – – – xiv
List of Appendices – – – – – – – – – xv
CHAPTER ONE
1.0 Introduction – – – – – – – – – 1
1.1 Statement of research problem – – – – – – 3
1.2 Justification of the study – – – – – – – 4
1.3 Aims and objectives – – – – – – – – 4
CHAPTER TWO
2.0 Literature Review – – – – – – – – 5
2.1 Cellulose – – – – – – – – – 5
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2.1.1 Brief history of cellulose – – – – – – – 5
2.1.2 Occurrence of cellulose – – – – – – – 6
2.1.3 Sources of cellulose – – – – – – – – 6
2.1.4Crystallinity of cellulose – – – – – – – 8
2.1.5 Other components of the cell wall – – – – – – 11
2.2 Nanocrystalline cellulose – – – – – – – 13
2.2.1 Extraction of nanocrystalline cellulose – – – – – 14
2.2.2 Drying of nanocrystalline cellulose – – – – – – 14
2.2.3 Modification of nanocrystalline cellulose – – – – – 16
2.2.4 Applications of nanocrystalline cellulose – – – – – 19
2.3 Textile Dyes – – – – – – – – – 20
2.3.1 Direct dyes – – – – – – – – – 21
2.3.3 Reactive dyes- – – – – – – – – 22
2.3.3 Disperse dyes – – – – – – – – – 23
2.4 Textile Dyeing – – – – – – – – – 23
2.4.1 Forces responsible for dye-fibre attraction – – – – – 24
2.5 Review of Nanocrytalline Cellulose – – – – – – 25
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CHAPTER THREE
3.0 MATERIALS AND METHODS – – – – – – 28
3.1 Materials – – – – – – – – – 28
3.2 Equipment- – – – – – – – – 28
3.3 Methods – – – – – – – – – 29
3.3.1 Collection of raw material – – – – – – – 29
3.3.2 Purification and removal of lignocellulosic materials – – – 30
3.3.3 Extraction – – – – – – – – – 30
3.3.4 Characterization – – – – – – – – 31
3.3.4.1 Scanning Electron Microscopy (SEM) – – – – – 31
3.3.4.2 Fourier-transformed Infrared Spectroscopy (FT-IR) – – – 32
3.3.4.3 X-ray Difftaction Analysis (XRD) – – – – – – 32
3.3.4.4 Thermogravimetric Analysis (TGA) – – – – – 32
3.3.4.5 Swelling Test – – – – – – – – 33
3.3.4.6 Density Determination – – – – – – – 33
3.3.4.7 Particle Size Analysis – – – – – – – 34
3.3.5 Dyeing – – – – – – – – – – 34
3.3.5.1 Dyeing with Direct dye – – – – – – – 34
3.3.5.2 Dyeing with Reactive dye – – – – – – – 35
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3.3.5.3 Dyeing with Disperse dye – – – – – – – 36
3.3.6 Determination of percentage exhaustion – – – – – 36
3.3.7 Determination of percentage fixation – – – – – – 37
3.3.8 Colour fastness tests – – – – – – – – 37
3.3.8.1 Washing fastness – – – – – – – – 37
3.3.8.2 Light fastness – – – – – – – – 38
3.3.8.3 Fastness to chlorinated water – – – – – – 38
CHAPTER FOUR
4.0 Results – – – – – – – – – – 39
4.1 Yield analysis – – – – – – – – – 39
4.2 Scanning Electron Microscopy (SEM) – – – – – 40
4.3 Fourier-transformed Infrared Spectroscopy (FT-IR) – – – 41
4.4 X-ray Diffraction Analysis (XRD) – – – – – – 43
4.5 Thermogravimetric Analysis (TGA) – – – – – – 45
4.6 Swelling test – – – – – – – – – 47
4.7 Density test – – – – – – – – – 47
4.8 Particle Size Analysis – – – – – – – – 48
4.9 Percentage exhaustion and fixation – – – – – – 49
4.10 Colour fastness – – – – – – – – 50
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CHAPTER FIVE
5.0 Discussion – – – – – – – – – 51
5.1 Yield analysis – – – – – – – – – 51
5.2 Scanning Electron Microscopy (SEM) – – – – – 51
5.3 Fourier-transformed Infrared Spectroscopy (FT-IR) – – – 52
5.4 X-ray Diffraction Analysis (XRD) – – – – – – 53
5.5 Thermogravimetric Analysis (TGA) – – – – – – 53
5.6 Swelling test – – – – – – – – – 54
5.7 Density test – – – – – – – – – 55
5.8 Particle size analysis – – – – – – – – 55
5.9 Percentage exhaustion and fixation – – – – – – 55
5.10 Colour fastness – – – – – – – – 56
CHAPTER SIX
6.0 Summary, Conclusion and Recommendations – – – – 59
6.1 Summary – – – – – – – – – 59
6.2 Conclusion – – – – – – – – – 60
6.3 Recommendations – – – – – – – – 61
References – – – – – – – – – – 62
Appendices – – – – – – – – – – 67
CHAPTER ONE
1.0 INTRODUCTION
Cellulose is the most abundant natural biopolymer on earth, which is renewable, biodegradable, as well as non-toxic. It is a carbohydrate polymer made up of repeating β-D-glucose units. It consists of both amorphous and crystalline regions (Coffey et al., 1995; Lima and Borsali, 2004).
The repeating unit of cellulose is cellobiose. Hydroxyl groups present in cellulose macromolecules are involved in a number of intra- and intermolecular hydrogen bonds, which result in various ordered crystalline arrangements. Four different crystalline allomorphs have been identified by their characteristic X-ray diffraction (XRD) patterns and solid-state 13C nuclear magnetic resonance (NMR) spectra: celluloses I, II, III and IV. Cellulose I is the most abundant form found in nature. Cellulose II can be prepared by two distinct routes: mercerization (alkali treatment) and regeneration (solubilisation and subsequent recrystallization). Celluloses IIII and IIIII can be formed from celluloses I and II, respectively, by treatment with liquid ammonia, and the reaction is reversible (Hayashi et al., 1975). Celluloses IVI and IVII can be obtained by heating celluloses IIII and IIIII, respectively (Gardinerand Sarko, 1985).
Cellulose, being the main building block of plant, is available in large quantities in the agricultural products and their wastes. These agricultural wastes are produced all over Nigeria and their disposal is a problem as every part of the country has its own dominant crops and therefore different agricultural wastes to deal with. An estimate of agricultural
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wastes produced in Nigeria in 2004 was made independently by two researchers(Osaghae, 2009 and Jekanyinfa and Scolz, 2007).
Table 1.1:Crop residue generation in Nigeria.
Crop residue
Total amount (Metric tonnes)
Cassava
29,000,000
Yam
22,000,000
Millet
11,000,000
Maize
3,500,000
Rice
1,800,000
Potato
600,000
Cowpea
4,050,000
Groundnut
6,000,000
Oil palm
400,000
Sugar cane
300,000
Sweet potato
1,000,000
Cocoyam
1,500,000
Coffee
400,000
Cashew
300,000
Plantain
9,450,000
Sorghum
1,500,000
Although other methods of controlling these crop residues are being employed in the various locations where they are produced, the conversion of these materials into useful
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productsis a recent development. These include the conversion of biomass into biofuel (mainly bioethanol) and extraction of cellulose (refined cellulose, microcrystalline cellulose and nanocrystalline cellulose).
Nanocrystalline cellulose (NCC) is a kind of renewablenatural resource. It is typically rod-shaped monocrystalline cellulose with tens to hundreds of nanometers in length and 1 – 100 nm in diameter (Ruiz et al., 2000).
Nanocrystalline cellulose (NCC) is an emerging renewable nano material that holds promise in many different applications, such as foods, pharmaceuticals, personal care, etc. Its properties and many potential forms allow many uses which, in addition to the afore mentioned, are iridescent magnetic films, improved construction products, biocomposite for bone replacement, paint additives, reinforced composites, recyclable interior and structural components for the transportation industry (Coffey et al., 1995; Lima and Borsali, 2004).
In this work, NCC will be produced using acid hydrolysis of corn cob powder. Other processes that can be applied to manufacture NCC are enzymolysis and chlorine oxidation degradation. Although these other processes have been attempted and each has its own peculiar effects on the resulting NCC, theacid hydrolysisis a well-known process used to dissolve the amorphous regions of cellulose effectively (Baiet al., 2009).
1.1 STATEMENT OF RESEARCH PROBLEM
Although research works have been reported on various aspects of NCC and its modification, there is still scanty literature on its colouration. Also, there is need to identify which class of dye will best suit its colouration process.
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1.2 JUSTIFICATION OF STUDY
Corn cob represents a large portion of our agricultural wastes, especially in northern region of the country where maize is one of the largely produced grains from subsistence farming. As a result, various research outlets have tried devising means of reducing this waste into useful products. This research has its significance reflected both in economic and environmental management of these wastes.
1.3 AIM AND OBJECTIVES
AIM
To extract, characterize and colour NCC from corn cob (waste to wealth).
OBJECTIVES
To characterize the extracted NCC using FTIR, SEM, PSA, TGA and XRD analysis.
To colour the produced NCC using reactive, disperse and direct dyes.
To identify the most suitable dye class for the extracted NCC.
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