A Lecture delivered to the Society on 14th January, 1955. WAX AND THE COSMETIC CHEMIST L. IVANOVSZKY, D.Sc. The author discusses the meaning ot• [he term •'wax," discards chemical detiinitions and l•rOl•OUnds a classification based on physical structure. INTROr)UC•NG MY lecture, I wish to mention that I do not pretend to be a cosmetic chemist myself. It is therefore obvious that it is not my intention to deal with specific cosmetics' problems. The only excuse I may claim to address you relates to the somewhat remote fact that at one time, in my younger days, I was in charge of a soap and cosmetics works. Since then I have retained a certain interest in the use of waxes, fats and oils, also in the field of cosmetics. The field of wax application covers numerous industrie• whereby it is important to realise that they are used for a variety of different purposes. In the order of approximate consumption, waxes are used as paper impreg- nants, solid illuminants, match impregnants, fruit and food preservatives, electrical and wireless insulants, as well as for the manufacture of polishes, a variety of stationery materials, cosmetics, pharmaceuticals and many other articles of commerce. In addition, waxes are albo used as starting materials for chemical conversion--for instance, by chlorination, oxidation, cracking and polymerisation. It is interesting to note that the assessed annual consumption of waxes and related materials by the U.S.A. cosmetic and pharmaceutical industries amounts to 2,700 tons, or oe1,I00,000. The quantity figure corresponds to about 0-6 per cent of the total U.S.A. wax consumption.• Another angie of wax application gives further insight into the multitude of requirements and problems involved---namely, the fact that •waxes are used in the solid state as well as in the form of solvent solutions and pastes, and in that of a variety of emulsions. In this short introduction, reference should be made to two groups of commoditiesmnamely, "waxes" and "related materials." It seems, there- fore, necessary to outline the past and present concepts of wax and to' consider the meaning of "related material," realising that. representatives of both classes are of importance to the cosmetic chemist. This consideration involves such problems as the appropriate selection of raw materials for a 130

WAX AND THE COSMETIC CHEMIST particular purpose or function, and the use of suitable methods for analysis and technological evaluation as well as theoretical aspects of wax chemistry and physics. THE CONCEPT OF WAX During the past thirty years a considerable number of new types of synthetically produced waxes and related materials has been introduced necessitating a new approach to chemistry, technology and analytical evaluation of waxes. As a result the old-established concept and definition of the term "wax" have become more and more a hindrance to scientific and technological development and have, therefore, to be replaced. Until recently, sole emphasis was laid on the chemical composition of a commodity called wax, irrespective of whether it concerned a liquid, a semi- solid or a solid. Accordingly, sperm oil, for instance, was considered a wax, but paraffin wax, to give an example, a non-wax. These views have drastically changed, since it has been realised that the nature of wax, both scientifically and in its technological implications, can only be explained by a peculiar physical structure which is solely responsible for the great majority of industrial uses of waxes. Thus the somewhat wilfully introduced fat-chemical definition of wax can no longer be regarded as adequate or useful and has to be replaced by another one, based on con- sistency and applicability. In other words, certain specific, technological properties have become the definitive characteristics of "wax." From a chemical point of view waxes have only one feature in common, the chain-character of their building stones. The physical requirements concern optimum length of the chains and absence of cross-linkages between them. The optimum length of a chain depends largely on its chemical nature and structure in particular, the degree of polarity and branching. Elaborat- ing the physical nature of wax, it must be stated that waxes should no longer be regarded as mechanical mixtures of a number of chemical com- pounds, but as characteristic physical systems. It must be added that the latter depend to some extent, as already indicated above, on the type of wax concerned. The three main variables--length of chain, polarity and branch- ing--govern nature and properties of a particular substance. Chains below optimum length favour the formation of semi-solid, more or less fat-like masses, whilst much longer chains may lead to thermoplastics. A high degree of branching, particularly of relatively short chains, will, as a rule, represent oily or fatty materials, and in the case of very long chains, glasses. Location, length or size and nature of the side chains or branches are also of influence on the resulting structure and thus its properties. All waxes possess a certain degree of crystallinity, depending on the particular type. The crystallinity itself is related to the degree and nature of branching, in conjunction with the length and polarity of the chains. As 131