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]. Soc. Cosmet. Chem., 23, 153-163 (March 3, 1972) Determination of the Molecular Weight Distribution of Polyether Surfactants NORMAN KALISH, M.S., • LEONARD WEINTRAUB, Ph.D., • and MARIE KOWBLANSKY, M.S.* Presented May 24, 1971, Seminar, Washington, D.C. Synopsis--Many of the characteristics which are important in formulating with POLY- ETHER SURFACTANTS are dependent on MOLECULAR WEIGHT DISTRIBUTION. The determination of the molecular weight distribution of a commercial quaternary am- monium polyether surfactant is reported. The intermediate tertiary aminopolyether alco- hol which contains polypropylene glycol as a by-product has a distribution identical to that of the quaternary products and was used in the analyses. The amine and glycol fractions were separated by esterification of the mixture, which permits partitioning of the esterified amine and glycol fractions into different solvents. The makeup of each fraction was determined by integrated programmed GAS CHROMATOGRA- PHY. In addition, the aminopolyether fraction was analyzed by a comb[nation o,f MASS SPECTROSCOPY and NUCLEAR MAGNETIC RESONANCE. The amine fraction was found to have a symmetrical distribution of molecular weights, while the glycol fraction had more high molecular weight than low molecular weight com- ponents. This method for determination of the molecular weight distribution is readily adapted to other polyether surfactants. INTRODUCTION Polyether surt•actants are employed in a variety of cosmetic prod- ucts. In most cases, the average molecular weight of the polyether is * Research and Development Laboratories, Bristol-Myers Products, 1350 Liberty Ave., Hillside, N. J. 07207. ? Present address, Warner-Lambert Research Institute, Morris Plains, N.J. 07950. 153