Evaluation of the antimicrobial effect and strength properties of polyester, polyester/cotton and

201 Pages·2012·1.27 MB·English

Evaluation of the antimicrobial effect and strength
properties of polyester, polyester/cotton and cotton treated
with Anolyte.

Jana F. Vermaas

Thesis submitted in accordance with the requirements for the degree

Philosophiae Doctor

in the
Faculty of Natural and Agricultural Sciences
Department of Consumer Science
at the
University of the Free State, Bloemfontein, South Africa

Promoter: Professor H.J.H. Steyn
Co-promoter: Professor C. Hugo
ACKNOWLEDGEMENTS

A major research project like this is never the work of anyone alone. The contributions of
many different people, in their different ways, have made this possible. I would like to extend
my appreciation especially to the following.
Foremost, I would like to express my sincere gratitude to my promoter Professor Hester
Steyn. It is difficult to state my gratitude. Thank you for the continuous support of my Ph.D
study and research, for her patience, motivation, enthusiasm, and immense knowledge. To my
co-promoter Professor Celia Hugo, thank you for your enthusiasm, inspiration, and great
efforts to explain things clearly and simply. Their guidance helped me immensely with the
completion of the research and writing of this thesis.

I would also like to thank Mrs. Rosalie Hunt for her kind assistance and patience in the
laboratory; it would never have been possible without her.

I wish to acknowledge Professor Schall for the statistical analysis and interpretation of the
results obtained in this study.

Thanks are due to Mrs. Adine Gericke and the assistants from the University of Stellenbosch,
Textile Science for their assistance and the use of their laboratory.

Thank you to my colleagues at the Department of Consumer Science for your support and
encouragement. Especially to Natasha van Heerden for her continued support through the
good and the bad, in the office and the lab.

To my friends and family: Thank you for all your support, encouragement and prayers.
Especially to my parents, thank you for the unconditional support and love throughout the
years.

Last but not least, to my Husband, Ruan. I do not have the words to express my gratitude,
thank you for everything!
i
TABLE OF CONTENTS
Chapter 1 PAGE
1.1 Introduction 1
1.2 Problem statement 3
1.3 Aims 4
1.4 Hypotheses 5
1.5 Terminology 6
Chapter 2: Literature Review
2.1 Introduction 8
2.2 Anolyte 9
2.2.1 Development of electrochemically activated water 9
2.2.2 Production of electrochemically activated water 10
2.2.3 The antimicrobial mechanisms of Anolyte 13
2.2.4 Successful use of Anolyte 15
2.3 Disinfectants 19
2.3.1 Sodium hypochlorite 19
2.3.2 Antimicrobial mechanisms of disinfectants 22
2.4 Laundering and temperature 23
2.5 Laundry detergents 25
2.5.1 Composition of Detergents 26
2.5.2 Antimicrobial efficacy of detergents 29
2.6 Environmental impacts of disinfectants and detergents 30
2.7 Microorganisms 31
2.7.1 Escherichia coli 33
2.7.1.1 Characteristics 33
2.7.1.2 Biochemical and culture characteristics 34
2.7.1.3 Distribution 34
2.7.1.4 Virulence Characteristics 35
2.7.1.5 Capsules of E. coli 35
2.7.1.6 Escherichia coli in food chains 36
2.7.2 Staphylococcus aureus 37
ii
2.7.2.1 Characteristics 37
2.7.2.2 Biochemical and culture characteristics 37
2.7.2.3 Distribution 37
2.8 Textile materials as a disease vector 38
2.9 Textile fibres 40
2.9.1 Cotton 41
2.9.1.1 Production 41
2.9.1.2 Structure 41
2.9.1.3 Chemical composition and Molecular arrangement 43
2.9.1.4 Physical properties 44
2.9.1.5 Mechanical properties 45
2.9.1.6 Chemical properties 46
2.9.1.7 Chemical reactivity 47
2.9.1.8 Sustainability and environmental concerns 48
2.9.2 Polyester 51
2.9.2.1 Production 51
2.9.2.2 Generic groups 53
2.9.2.3 Structure 54
2.9.2.4 Physical properties 55
2.9.2.5 Mechanical properties 55
2.9.2.6 Chemical properties 56
2.9.2.7 Chemical reactivity 58
2.9.2.8 Biological properties 59
2.9.2.9 Sustainability and environmental concerns 59
2.9.3 Polyester/Cotton 60
2.10 Antimicrobial finishes as an alternative to fabric disinfection 61
2.11 Conclusion 63

Chapter 3: Materials and Methods
3.1 Materials 64
3.1.1 Preparation of wash liquors 64
3.1.1.1 Anolyte 64
3.1.1.2 Detergent solution 65
iii
3.1.1.3 Sodium hypochlorite bleach solution 66
3.1.1.4 Filtered water 66
3.2 Textile fabrics 67
3.3 Methods 67
3.3.1 Antimicrobial effect 67
3.3.1.1 Bacterial strains and culture media 67
3.3.1.2 Preparation of inocula 68
3.3.1.3 Inoculation of textiles 68
3.3.1.4 Treatment of fabrics 68
3.3.1.5 Determination of effectiveness of wash liquors 68
3.4.1 Fabric properties 69
3.4.1.1 Laundering 69
3.4.1.2 Dimensional stability 69
3.4.1.3 Tearing Strength 69
3.4.1.4 Tensile Strength 70
3.4.1.5 Statistical Analysis 70

Chapter 4: Determination of antimicrobial efficacy
4.1 Escherichia coli survival 72
4.2 Staphylococcus aureus survival 78

Chapter 5: The effect of Anolyte, detergent, sodium hypochlorite solution
and water on the strength and dimensional properties of cotton, polyester
and polyester/cotton
5.1 Dimensional stability 84
5.2 Tensile strength 85

5.2.1 Maximum load required to break the fabrics after laundering with the water,
detergent, Anolyte and sodium hypochlorite
5.2.1.1 Cotton 86
5.2.1.2 Polyester 95
5.2.1.3 Polyester/Cotton 104

iv
5.2.2 Displacement at maximum load
5.2.2.1 Cotton 112
5.2.2.2 Polyester 118
5.2.2.3 Polyester/Cotton 125

5.3 Tearing strength
5.3.1 Cotton 131
5.3.2 Polyester 138
5.3.3 Polyester/Cotton 144

Chapter 6: Conclusion & Recommendation
6.1 Conclusion 152
6.2 Recommendation 158

References 159
Abstract 184
Opsomming 186

v
LIST OF FIGURES

PAGE
Figure 2.1: Production of electrolyzed water. 10

Figure 2.2: The submicroscopic structure of cotton fibre. 42

Figure 2.3: Repeating unit of cellulose 43

Figure 2.4: The melt spinning processes for filament and staple fibres. 52

Figure 3.1: An illustration of the water electrolyzer unit. 64

Figure 4.1: The effects of the laundering treatments on the survival of E. coli on polyester,
polyester/cotton and cotton at 24°C. 74

Figure 4.2: The effects of the laundering treatments on the survival of E. coli on polyester,
polyester/cotton and cotton at 30°C. 76

Figure 4.3: The effects of laundering treatments on the survival of Staph. aureus on
polyester, polyester/cotton and cotton fabrics at 24°C. 80

Figure 4.4: The effects of laundering treatments on the survival of Staph. aureus on
polyester, polyester/cotton and cotton fabrics at 30°C. 82

Figure 5.1: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the maximum load of the cotton fabric. 86

Figure 5.2: Maximum load of the cotton fabric after laundering for five, ten and twenty
cycles at 24°C. 90

Figure 5.3: Maximum load of the cotton fabric after laundering for five, ten and twenty
cycles at 30°C. 92

vi
Figure 5.4: Maximum load of the cotton fabric after laundering for five, ten and twenty
cycles at 60°C. 93

Figure 5.5: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the maximum load of the polyester fabric. 96

Figure 5.6: Maximum load of the polyester fabric after laundering for five, ten and twenty
cycles at 24°C. 99

Figure 5.7: Maximum load of the polyester fabric after laundering for five, ten and twenty
cycles at 30°C. 100

Figure 5.8: Maximum load of the polyester fabric after laundering for five, ten and twenty
cycles at 60°C. 102

Figure 5.9: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the maximum load of the polyester/cotton fabric. 104

Figure 5.10: Maximum load of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 24°C. 107

Figure 5.11: Maximum load of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 30°C. 108

Figure 5.12: Maximum load of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 60°C. 110

Figure 5.13: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the displacement at maximum load of the cotton fabric. 112

Figure 5.14: Displacement of the cotton fabric at maximum load after laundering for five, ten
and twenty cycles at 24°C. 115

vii
Figure 5.15: Displacement of the cotton fabric at maximum load after laundering for five, ten
and twenty cycles at 30°C. 116

Figure 5.16: Displacement of the cotton fabric at maximum load after laundering for five, ten
and twenty cycles at 60°C. 117

Figure 5.17: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the displacement at maximum load of the polyester fabric. 120

Figure 5.18: Displacement of the polyester fabric at maximum load after laundering for five,
ten and twenty cycles at 24°C. 122

Figure 5.19: Displacement of the polyester fabric at maximum load after laundering for five,
ten and twenty cycles at 30°C. 123

Figure 5.20: Displacement of the polyester fabric at maximum load after laundering for five,
ten and twenty cycles at 60°C. 124

Figure 5.21: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the displacement at maximum load of the polyester/cotton fabric. 127

Figure 5.22: Displacement of the polyester/cotton fabric at maximum load after laundering
for five, ten and twenty cycles at 24°C. 128

Figure 5.23: Displacement of the polyester/cotton fabric at maximum load after laundering
for five, ten and twenty cycles at 30°C. 129

Figure 5.24: Displacement of the polyester/cotton fabric at maximum load after laundering
for five, ten and twenty cycles at 60°C. 130

Figure 5.25: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the tearing strength of the cotton fabric. 131

viii
Figure 5.26: Tearing strength of the cotton fabric after laundering for five, ten and twenty
cycles at 24°C. 134

Figure 5.27: Tearing strength of the cotton fabric after laundering for five, ten and twenty
cycles at 30°C. 135

Figure 5.28: Tearing strength of the cotton fabric after laundering for five, ten and twenty
cycles at 60°C. 136

Figure 5.29: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the tearing strength of the polyester fabric. 138

Figure 5.30: Tearing strength of the polyester fabric after laundering for five, ten and twenty
cycles at 24°C. 141

Figure 5.31: Tearing strength of the polyester fabric after laundering for five, ten and twenty
cycles at 30°C. 142

Figure 5.32: Tearing strength of the polyester fabric after laundering for five, ten and twenty
cycles at 60°C. 143

Figure 5.33: The influence of laundering with water, detergent, Anolyte and sodium
hypochlorite on the tearing strength of the polyester/cotton fabric. 146

Figure 5.34: Tearing strength of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 24°C. 148

Figure 5.35: Tearing strength of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 30°C. 149

Figure 5.36: Tearing strength of the polyester/cotton fabric after laundering for five, ten and
twenty cycles at 60°C. 150

ix