420 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Poly(oxytetramethylene) poly(glyceryl) alkyl ether random copolymers (RnTxGy) have been synthesized and studied to see if they might display improved properties. The following characteristics were investigated: 1) solution properties, 2) HLB-value, 3) emulsifying ability, 4) phase behavior of surfactant/oil/water system, 5) properties as moisturizers, 6) chemical stability, and 7) safety when used on the skin. EXPERIMENTAL SYNTHESIS The synthesis of R12T2.2G3.1 is shown in Figure 1. To a refluxing solution of lauryl alcohol (62.1 g, 0.33 mob, boron trifluoride ethyl ether complex (0.5 g, 0.0035 mol), and THF (180.3 g, 2.5 mob, a freshly distilled solution of gtycidol (74.1 g, 1 mol) in THF (36.1 g, 0.5 mol) was added dropwise. When the addition was complete (about 1 hr), the solution was refluxed for an additional hour. After the mixture cooled to room temperature, sod. ium bicarbonate (20 g) was added and stirred over a period of two hours. The mixture was then filtered and evaporated under a reduced pressure. Thus R12T2.2G3.1 was obtained in an oily state (yield, 202 g). Lauryl alcohol 1.0 mol Tetrahydrofuran(THF) Boron trifluoride ethyl ether 7.5 mol 1.5 g Glycidol 3.0 mol THF 1.5 mol J Sodium bicarbonate 60.0 g 64-65'C Stirring I hr Stirring Neutralization Filtration Evaporation [ R,2T2.2G3., 606 cJ l Ci2H250H + xCH2CH2CH2CH2? + yHOCH21CHCH210 I (C2H5)20' BF3 THF = C 12H250[(CH2)40]x[IC3H5{O H)OJyH Figure 1. Synthesis of poly(oxytetramethylene) (2.2) poly(glyceryl) (3.1) lauryl ether (R•2T2.2G3.•).

POLY(GLYCERYL) ALKYL ETHER SURFACTANTS 421 PROPERTIES Nonionic surfactant, water, and liquid paraffin were put into test tubes that had teflon sealed screw caps. The test tubes were repeatedly shaken in a thermostated bath until the solutions reached an equilibrium state. The solubility regions were determined by visible observations. The liquid crystalline structure was determined by a polarizing microscope (Olympus, BH-2) and an X-ray low-angle diffractometer (Rigaku Co.). Surface tension measurements were made by the Wilhelmy plate technique at 25øC. The formaldehyde given off was determined by the acetylacetone method (13). For determining HLB value, hydrophilic nonionic surfactants were combined with sor- bitan monostearate (HLB-v = 4.7), and lipophilic nonionic surfactants were combined with POE (20) sorbitan monostearate (HLB-v -- 14.9). Liquid paraffin-water systems were emulsified by the combined surfactants. Phase inversion emulsification was used to determine the HLB-value (14). The required HLB value of the liquid paraffin was 11.2. The HLB-values of RnTxGy were calculated from the ratio of the weights of two surfactants which gave the finest O/W emulsions. The mean particle size of the O/W emulsions was measured by the centrifugal sedimentation method (Horiba, CAPA-500). The skin irritation potential of RnTxGy was tested by applying it three times to the bare skin of rabbits over a three-day period. Each test site was evaluated 0 (for non-visible) to 3 (for severe responses) 24, 48, and 72 hours after application. Cellular skin injury from topically applied substances was characterized by a local inflammatory response, mani- fested by three important macroscopically visible events: reddening of the skin (ery- thema), accumulation of fluid (edema), and vasodilation. The total score of the mean inflammatory response for six rabbits was recorded as the Primary Irritation Index (PII, maximum = 9). For the eye irritation test, an aqueous surfactant solution of 0.05 ml was instilled into one eye of each rabbit. The other eye acted as control. Observations were made 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, and 24 hours after instillation. Lesions in the conjunctiva, nictating membranes, and cornea were scored separately using a numerical system based on the modified procedure of Draize et al. (15). The scores used were 0 for non-visible to 4 for a severe response. The theoretical maximum score is 96. RESULTS AND DISCUSSION SYNTHESIS OF RnTxGy R•2T•Gy and R•8T•Gy were synthesized from lauryl or stearyl alcohol (1 mol), glycidol (y mol), and THF (3y mol). The structure and average molecular weights were deter- mined by •H-NMR spectroscopy. The assignment of the peaks of acetylated R•2T7.sG7. 9 is shown in Figure 2. The average chain lengths of the oxytetramethylene units (x) and the glyceryl units (y) can be calculated by integration of the alkyl chain proton peak (b), the tetramethylene proton peak (c), and the acetyl proton peak (d). The C/B ratio is given by C/B = (4x + 2)/2(n - 3) forx = (n- 3)(C/2B) - 1/2. The D/B ratio becomes D/B = (3y + 3) / 2(n - 3) for y = (n - 3) (2D/3B) - 1, where n