Chemical and Physical Behavior of Human Hair Fourth Edition Springer New York Berlin Heidelberg Barcelona Hong Kong London Milan Paris Singapore Tokyo Clarence R. Robbins Chemical and Physical Behavior of Human Hair Fourth Edition With 111 Figures 13 Clarence R.Robbins 12425 Lake Ridge Circle Clermont,FL 34711 USA Library of Congress Cataloging-in-Publication Data Robbins,Clarence R. Chemical and physical behavior of human hair / Clarence R.Robbins.– 4th ed. p.cm. Includes bibliographical references and index. ISBN 0-387-95094-X (alk.paper) 1. Hair. I. Title. QP88.3 .R62 2000 612.7¢99 – dc21 00-059475 Printed on acid-free paper. The first edition was published by Van Nostrand Reinhold Company in 1979 under the same title. © 2002,1994,1988 Springer-Verlag New York,Inc. All rights reserved.This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag New York,Inc.,175 Fifth Avenue,New York,NY 10010,USA),except for brief excerpts in connection with reviews or scholarly analy- sis.Use in connection with any form of information storage and retrieval,electronic adapta- tion,computer software,or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names,trade names,trademarks,etc.,in this publication,even if the former are not especially identified,is not to be taken as a sign that such names,as under- stood by the Trade Marks and Merchandise Marks Act,may accordingly be used freely by anyone. Production coordinated by Chernow Editorial Services, Inc., and managed by Mary Ann Brickner;manufacturing supervised by Joe Quatela. Typeset by Best-set Typesetter Ltd.,Hong Kong. Printed and bound by Maple-Vail Book Manufacturing Group,York,PA Printed in the United States of America. 9 8 7 6 5 4 3 2 1 ISBN 0-387-95094-X SPIN 10768684 Springer-Verlag New York Berlin Heidelberg A member of BertelsmannSpringer Science+Business Media GmbH To my wife,Gene,for 41 years of hope,making every day a day of joy.To my father,an example for me and an inspiration to many.To my mother,who struggles with her aches and pains and tries to be cheerful in her nineties. To my daughter, Laurie, and her husband,T.J.;to my son,Mark,and his wife,Kim;to my brother, John, and his family; to my mother-in- law,Daun,whom we all miss so much and my father- in-law,Gordon;to Becky;to Ken and his family;and to my many other relatives and friends who help to make life meaningful for me.I would also like to ded- icate this fourth edition to four colleagues who had a very positive influence on my career in science. To John Wright, who initiated my interest in chemistry; to Bill Truce,who taught me to work as an indepen- dent scientist;to George Scott,my mentor in keratin fiber science;and to Charles Reich,who calls me his mentor but added so much to my life and career in hair science. Preface to the Fourth Edition Nearly seven years have elapsed since the writing of the third edition of this book, and many advances in hair science have been made in that interval. In addition, several new/unpublished electron micrographs have been made available from three different sources. Dr. Sigrid Ruetsch has kindly provided me with several micrographs from her hair fracturing studies. I have selected several others from new literature, and from my own files I have selected relevant micrographs that were never published before. Many of these micrographs reveal details of hair damage from grooming-type actions and from permanent waves,bleaches,and oxidative treatments of hair,which are among the most important areas of current hair research. New studies on hair growth and structure have provided a better under- standing of the epicuticle and hair protein structures,and the relationship between hair proteins and genes is beginning to fit together in a more mean- ingful manner.Growth factors are better understood,a second legitimate hair growth product has been marketed,and a new active ingredient that shortens the anagen growth period is being pursued in a product to help control facial hair in women.New evidence exists today to view dandruff as an inflammatory disease rather than as a disease simply of fungal origin, and a new section on toxicity has been added with special focus on skin irri- tation leading to a model that predicts relative skin irritation by shampoos and other surfactant formulations. Also, evidence has been provided to show how hair fiber shape can influence physicochemical actions in hair fibers,and,thanks to the advice of a reviewer,new sections on hair straight- ening and depilation have been added to this edition.I have also attempted to summarize the status of the effects of the 55% VOC-CARB regulatory action on hair sprays and the other CARB actions on other hair fixative products. This new edition is not only updated, but it also fills the gaps of prior editions.Thus,it remains my hope that this book will continue to provide a convenient starting point for hair research, to serve as a stimulus to vii viii Preface to the Fourth Edition academia by offering examples of classical applied science in an area of interest to lay persons and, as indicated in the first edition, not to be the final word. CLARENCE R.ROBBINS Preface to the Third Edition More than five years have elapsed since I completed the second English edition of this book and fifteen years since the first edition. During that interim,this book has been translated into Japanese and a Russian trans- lation is well on its way.In addition,many advances have been made in both our understanding of the structure of human hair,of the chemical and phys- ical mechanisms of how cosmetics work,and in improved hair products in the marketplace. For example,the cuticle of human hair is largely a protective barrier that does not participate directly in the tensile strength of human hair.The struc- ture of the cortex is now known to consist of intermediate filamentous type proteins that are surrounded by highly cross-linked sulfur rich proteins.The intercellular regions are largely non-keratinous and have been demon- strated to be highly important to the penetration and to the swelling behav- ior of the fiber.The mechanism of chemisorption onto keratin fibers has been further elucidated leading to better conditioning shampoos than ever before, and although there are still many mysteries surrounding the bio- chemical mechanism of hair growth,we are at least beginning to understand some of the fundamental perplexities in this vast area of research. Thus,this new edition portrays human hair from these new perspectives and hopefully fulfills the original purpose: to provide a reasonably up to date and complete account of the chemical and physical properties and behavior of human hair.It is also my hope that this edition will provide a convenient starting point for hair research and serve as a stimulus to acad- emia by offering examples of classical applied science in an area of inter- est to most lay persons—and as indicated in the first edition,not to be the final word. CLARENCE R.ROBBINS ix Preface to the Second Edition Ten years have elapsed since I wrote the first English edition of this book, and progress in hair science has made a second edition necessary. Since 1978,at least two new major scientific cosmetic journals have appeared and four International Hair Science Symposia and one International Sympo- sium on Forensic Hair Comparisons have been held. Thus,continuing studies in hair science have been numerous in the past ten years, so much so that a large proportion of the text had to be com- pletely rewritten. In addition, a number of omissions that were kindly pointed out by reviewers have been included in this edition,as well as cor- rections sent to me by readers. I sincerely hope that this new edition fulfills the original purposes: to provide a reasonably up to date and complete account of the chemical and physical properties and behavior of human hair,to serve as a convenient starting point for hair research—and,as indicated in the first edition,not to be the final word. CLARENCE R.ROBBINS xi Preface to the First Edition In this book,I have tried to provide a reasonably up to date and complete account of the chemical and physical properties and behavior of human hair.Chapter 1 describes the structure of human hair,from the microscopic level down to the molecular level, Chapter 2 discusses its chemical com- position, and Chapters 3 through 7 emphasize the organic and physical chemistry of the reactions and interactions of hair with different cosmetic or potential cosmetic ingredients.The last chapter describes the physical behavior of hair before,during,and after cosmetic treatments. The principal audience is obviously the cosmetic and fiber industries and their suppliers,but it is my hope that the examples of physico-chemical con- cepts involving reaction mechanisms and structure elucidation might stim- ulate the academic world to become more actively involved in hair research and perhaps to offer some of these examples of classical applied science to inorganic and biochemistry courses. In many instances,reference is made to the wool literature,because it is more complete, and the two fibers are so similar. I have also taken the liberty to express my own opinions and generalizations on many of the sub- jects herein.I caution the reader not to be content with the generalizations I have made,but to examine the original data for himself.The purpose of this book is to serve as a convenient starting point,not to be the final word. CLARENCE R.ROBBINS xiii