Investigation on the thermal stability of technical and cosmetic emulsions [Elektronische Ressource] / vorgelegt von Cristina-Alina Iliescu

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2005
• Nombre de lectures: 8
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Investigation on the thermal stability of
technical and cosmetic emulsions


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-Physikerin
Cristina-Alina Iliescu
aus
Bukarest, Rumänien




Berichter: Prof.Dr.Dr.h.c. Hartwig Höcker
Prof.Dr. Franz-Josef Wortmann
Tag der mündlichen Prüfung: 1. März 2005
Diese Dissertation ist auf den Internetseiten der Hochschule online verfügbar




















































To my parents












































Motto:
„Wir sehen jetzt durch einen Spiegel
in einem dunkeln Wort;
dann aber von Angesicht zu Angesicht.
Jetzt erkenne ich es stückweise;
Dann aber werde ich es erkennen,
gleichwie ich erkannt bin.“
(I Korinther 13,12)













ACKNOWLEDGEMENTS


First of all I would like to thank Prof.Dr.Dr.h.c. Hartwig Höcker who honoured me by
accepting my PhD study under his coordination. I am greatly indebted to him for giving me
the opportunity to do the PhD thesis on a topic of such a great actual interest and also for
his generous and friendly support.
I would like to express my deep gratitude to Prof. Dr. Franz-Josef Wortmann for the
enlightening and stimulating discussions throughout the all three years of PhD study, for
the permanent encouragement and warm support. I deeply appreciate his careful and
exigent reading of the thesis, the critical comments, suggestions and corrections, which
allowed the initial version to improve significantly. Particularly, I wish to thank Prof. Dr.
Franz-Josef Wortmann for the pleasant and personal atmosphere in his working group.
My thanks go also to Prof. Dr. Crisan Popescu for the scientific discussions and help, for
sharing his knowledge with me the PhD time period. I would also like to thank him for
firstly correcting my PhD thesis and for eliminating the most unsatisfying English
formulations.
I would also like to greatly thank Univ.Lect.Dr. Marlies Fabry for the friendly acceptance of
the co-report.
I am thankful to all former and present collegues from DWI and especially from the joint
groups of Prof. Dr. Franz-Josef Wortmann and Dr. Gabriele Wortmann for the nice
atmosphere and for the time we spent together. In this context I would like to mention
Alina and Udo, Cristi, Stefan, Carla and Ricardo, Alexandra, Edith, Candy, Jo, Nadine,
Petra, Christiane, Jan, Georg, Carla, Elvira and last but not least the nice ladies Regina,
Brigitte, Marion and Birgit. A very special thank goes to Dr. Kim-Hô Phan. In good memory
I will keep also the great personality and nice man Prof.Dr.Dr.h.c. Helmut Zahn.
Many thanks go to IFF Hilversum B.V. (Hilversum, Nederland) for providing the fabric
softeners samples analysed in this work as well as financial support during part of the
project. This thesis was also possible due to the cosmetic creams and lotions received
from Beiersdorf AG (Hamburg, Germany). I would like to thank therefore this company for
making avaible these samples.


I am deeply grateful to my unforgetabble teachers from the high-school: Mrs. Marilena
Panaitopol, Mrs. Hortensia Bala şescu, Mr. Marcel Petri şor, Mr. Mircea Gheordunescu, Mr.
Petre Constantinescu and Mr. Ştefan Pascu for opening my eyes to the mysteries of the
world.
To come so far was also the merit of the wonderful professors I had the chance to have
during my study at the Faculty of Physics, University of Bucharest, Romania. Very grateful
I am to Prof.Dr. R ăzvan Bobulescu. I owe also enormously to all members of the
Department of Biophysics. My greatest appreciation and thanks go to Prof.Dr. Aurel
Popescu. In great recognition I would also like to mention Univ.Lect. Doina Gazdaru and
Dr. Puiu B ălan.
Many, many thanks I would like to express to my good friends Magda and Adriana in
Romania, Martin in Germany and to my cousin and friend Liviu. For the nice atmosphere
at home I also like to thank my family friends and relatives, especially to my aunts and
uncles Gabi and Bebe, Elena and Dan. I will also never forget the special moments spent
together with the nice family friend Dorin.
I am very grateful to my dear boy-friend Michael for his outstanding support, valuable
advices and for the critical and creative correction of the PhD thesis. I would like to thank
him for his tremendous confidence and for his special way of making come to light the
best of myself.
Very special thanks go to my sister Karina for our mutual and unconditional support and
friendship.
Last but not least, I am filled with a deep sense of gratitude to my beloved parents, Natalia
and Sergiu-Stelian Iliescu, for beleaving in me, for always understanding me and for
supporting me in every way. I know, however, that I will never be able to thank them
enough for what I am, for everything.

Contents

CONTENTS

Zusammenfassung III
Abstract VI
List of symbols VIII
1. Objectives of the investigation in the actual scientific perspective 1
2. Theoretical background 4
2.1. Emulsions 4
2.1.1. General considerations 4
2.1.2. Stability of emulsions 7
2.1.2.1. Thermodynamical aspects of emulsion stability 7
2.1.2.1.1. Charge stabilisation 7
2.1.2.1.2. Steric stabilisation 9
2.1.2.2. Main breakdown processes and methods of enhancing stability 12
2.1.3. Fabric softeners: a special kind of emulsion 15
2.2. Principles of thermal analysis 17
2.3. Kinetics of chemical reactions 20
2.3.1. Background of chemical reaction kinetics for thermal analysis 20
2.3.2. Non-isothermal reaction kinetics. Deconvolution procedure 23
3. Experimental part 31
3.1. Materials 31
3.2. Methods and instruments 32
4. Results and discussion 34
4.1. DSC investigations of fabric softeners 34
4.1.1. Investigations of three base formulations 34
4.1.1.1. Qualitative observations 34
4.1.1.1.1. Unperfumed samples. The concept of “rejuvenation” 34
4.1.1.1.2. Influence of fragrance addition 36
4.1.1.1.3. Infl storage time on unperfumed base 1 (B1_u) 43
4.1.1.1.4. Influence of low temperature storage on unperfumed base 1 (B1_u) 50
4.1.1.2. Kinetic analysis of DSC-curves 52
4.1.1.2.1. General kinetic description 53
4.1.1.2.1.1. Model-free approach 53
4.1.1.2.1.2. Model-based approach 58
4.1.1.2.2. Detailed kinetic description 63
4.1.1.2.2.1. Deconvolution with best fit conditions 63
4.1.1.2.2.2.olution with best fit and restrictions 66
I Contents

4.1.1.2.3. Kinetic analysis of unperfumed base 1 (B1_u) stored at low temperatures 74
4.1.1.3. Influence of the de-ageing 75
4.1.1.3.1. Unperfumed samples 75
4.1.1.3.2. Cooling curves 83
4.1.1.3.3. Perfumed samples 86
4.1.1.4. Influence of storage at high temperature on unperfumed bases 1 (B1_u)
and 2 (B2_u) 91
4.1.1.6. Conclusions 95
4.2. DSC investigation of commercial cosmetic creams and lotions 97
4.2.1. Qualitative observations 97
4.2.2. A commercial cosmetic o/w emulsion 100
4.2.3. A commercetic w/o emulsion 105
4.2.4. A commercial cosmetic w/o/w emulsion 108
5. Appendix 112
5.1. Statistics 112
5.2. Composition of commercial cosmetic emulsions 113
6. Conclusions 114
7. References 117








II