Fundamental properties of Afro-American hair as related to their straightening/relaxing behaviour

174 Pages·2004·5.66 MB·German

Fundamental properties
of Afro-American hair
as related to their
straightening/relaxing behaviour
Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der
Rheinisch-Westfälischen Technischen Hochschule Aachen
zur Erlangung des akademischen Grades eines Doktors
der Naturwissenschaften genehmigte Dissertation
vorgelegt von
Diplom-Chemikerin
Jutta Maria Quadflieg
geb. Bußmann
aus Dortmund
Berichter: Prof. Dr. Hartwig Höcker
Prof. Dr. Franz-Josef Wortmann
Tag der mündlichen Prüfung: 05. September 2003
Diese Dissertation ist auf den Internetseiten der Hochschule online verfügbar.

Für Joachim Für Joachim

"The secret of patience: Do something else in the meantime." "The secret of patience: Do something else in the meantime."

Detlev Rossilyo [American philosopher, born 1942] Detlev Rossilyo [American philosopher, born 1942]

Acknowledgements Acknowledgements

I would like to thank Prof. Dr. Dr. h.c. Hartwig Höcker for making this thesis I would like to thank Prof. Dr. Dr. h.c. Hartwig Höcker for making this thesis
possible and for his friendly support. possible and for his friendly support.

I am indebted to my outstanding supervisor Prof. Dr. Franz-Josef Wortmann for I am indebted to my outstanding supervisor Prof. Dr. Franz-Josef Wortmann for
critically reading the manuscript and letting me do exercises in patience. critically reading the manuscript and letting me do exercises in patience.

Special thanks go to Prof. Dr. Dr. h.c. mult. Helmut Zahn for intensive Special thanks go to Prof. Dr. Dr. h.c. mult. Helmut Zahn for intensive
discussions about hair. discussions about hair.

I would also like to gratefully acknowledge Namasté Laboratories L.L.C. for the I would also like to gratefully acknowledge Namasté Laboratories L.L.C. for the
financial support of the project and especially Mr. Gary Gardner for being financial support of the project and especially Mr. Gary Gardner for being
always very interested and supportive for my work. This thesis would hardly always very interested and supportive for my work. This thesis would hardly
have become possible without the critical and creative discussions with Dr. have become possible without the critical and creative discussions with Dr.
Leszek Wolfram. Leszek Wolfram.

I thank Dr. Hô Phan and Franz Steffens for preparing the electron microscopic I thank Dr. Hô Phan and Franz Steffens for preparing the electron microscopic
pictures. Moreover, I would like to give thanks to Dr. Carla Sanchez Scanavez pictures. Moreover, I would like to give thanks to Dr. Carla Sanchez Scanavez
de Paula for letting me use her SEM pictures. de Paula for letting me use her SEM pictures.

In great recognition of his service in performing amino acid analyses I would In great recognition of his service in performing amino acid analyses I would
like to mention Dr. Josef Föhles. like to mention Dr. Josef Föhles.

I would like to thank Dr. Rebecca Elliott for reducing my worst offences against I would like to thank Dr. Rebecca Elliott for reducing my worst offences against
the English language. the English language.

I am very grateful to all members of “Alte Bibliothek”. They made a big I am very grateful to all members of “Alte Bibliothek”. They made a big
contribution for me enjoying the time at DWI. contribution for me enjoying the time at DWI.

A very special thank goes to my beloved parents Franz-Josef and Barbara A very special thank goes to my beloved parents Franz-Josef and Barbara
Bußmann for their support in any situation. Bußmann for their support in any situation.

Finally, I am filled with a deep sense of gratitude to my beloved husband Finally, I am filled with a deep sense of gratitude to my beloved husband
Joachim Quadflieg. Without him I would not have come as far as I am now. Joachim Quadflieg. Without him I would not have come as far as I am now.

Table of contents Table of contents

Table of contents I Table of contents I

Summary V Summary V

List of abbreviations X List of abbreviations X

1. Objectives of the investigation 1 1. Objectives of the investigation 1

2. Introduction 4 2. Introduction 4

2.1. Human hair 4 2.1. Human hair 4
2.1.1. Structure of hair 4 2.1.1. Structure of hair 4
2.1.1.1. The cuticle 5 2.1.1.1. The cuticle 5
2.1.1.2. The cell membrane complex 6 2.1.1.2. The cell membrane complex 6
2.1.1.3. The cortex 7 2.1.1.3. The cortex 7
2.1.1.4. Cross-links in the proteins of hair 9 2.1.1.4. Cross-links in the proteins of hair 9
2.1.2. Origin of curls in Afro hair 10 2.1.2. Origin of curls in Afro hair 10

2.2. Hair straightening/relaxing 13 2.2. Hair straightening/relaxing 13
2.2.1. Thermal straightening – hair pressing 13 2.2.1. Thermal straightening – hair pressing 13
2.2.2. Chemical hair straightening 14 2.2.2. Chemical hair straightening 14
2.2.2.1. Differences between hair straightening and relaxing 14 2.2.2.1. Differences between hair straightening and relaxing 14
2.2.2.2. The chemistry of hair straightening 15 2.2.2.2. The chemistry of hair straightening 15
2.2.2.3. The history of hair relaxing 17 2.2.2.3. The history of hair relaxing 17
2.2.2.4. The chemistry of hair relaxing 18 2.2.2.4. The chemistry of hair relaxing 18
I I
Table of contents Table of contents

3. Results and discussion 19 3. Results and discussion 19

3.1. Investigations of hair cross-sections 19 3.1. Investigations of hair cross-sections 19
3.1.1. Introduction 19 3.1.1. Introduction 19
3.1.2. Influences of age and gender 21 3.1.2. Influences of age and gender 21
3.1.3. Comparison of pigmented and non-pigmented Afro hair 24 3.1.3. Comparison of pigmented and non-pigmented Afro hair 24

3.2. Comparison of Afro, Asian and Caucasian hair 26 3.2. Comparison of Afro, Asian and Caucasian hair 26
3.2.1. Characterization of hair samples 27 3.2.1. Characterization of hair samples 27
3.2.2. Hair treatments 29 3.2.2. Hair treatments 29
3.2.3. Quality of the hair samples after treatment 30 3.2.3. Quality of the hair samples after treatment 30
3.2.3.1. Surface quality of the hair 30 3.2.3.1. Surface quality of the hair 30
3.2.3.1.1. Scanning electron microscopy 30 3.2.3.1.1. Scanning electron microscopy 30
3.2.3.1.2. Gloss measurements 33 3.2.3.1.2. Gloss measurements 33
3.2.3.2. Amino acid composition 36 3.2.3.2. Amino acid composition 36
3.2.3.3. Thermal properties 51 3.2.3.3. Thermal properties 51

3.3. Evaluation of hair straightening efficacy 60 3.3. Evaluation of hair straightening efficacy 60
3.3.1. Relaxer creams 60 3.3.1. Relaxer creams 60
3.3.2. Treatments 60 3.3.2. Treatments 60
3.3.3. Procedure for single hair relaxing 61 3.3.3. Procedure for single hair relaxing 61
3.3.4. Results of single hair relaxing 63 3.3.4. Results of single hair relaxing 63
3.3.4.1. Comparison of simulated and natural Afro hair 63 3.3.4.1. Comparison of simulated and natural Afro hair 63
3.3.4.2. Comparison of different treatments of natural Afro hair 67 3.3.4.2. Comparison of different treatments of natural Afro hair 67

3.4. Study of hair relaxing 71 3.4. Study of hair relaxing 71
3.4.1. Kinetics of cystine degradation 71 3.4.1. Kinetics of cystine degradation 71
3.4.2. Quality of the hair after modified relaxer treatments 74 3.4.2. Quality of the hair after modified relaxer treatments 74
3.4.2.1. Amino acid composition 74 3.4.2.1. Amino acid composition 74
3.4.2.2. Thermal properties 87 3.4.2.2. Thermal properties 87
II II