HAIR WAVING PROPERTIES OF 2,5-DIMERCAPTOADIPIC ACID 259 Figure 1.--Distribution of sulfhydryl groups in cross section of hair following exposure to DMA lotion but before chemical neutralization (stained with NQ reagent described in text) o Making use of these properties it is possible to formulate powdered DMA compositions with suitable booster additives which will give wave levels in a CN or AO process which are equivalent to thioglycolate waves. Table 4 lists some such compositions. D. 14Zaving End Papers Impregnated with Booster/ldditives for DM/1 Lo- tions Because of the odor and stability advantages of DMA, it is desirable to formulate aqueous lotions based on this mercaptan for commercial use. •..... .: . • ,..•.•...,:(.' • - : .. • •.• . ':'.: '•' •i ':?-,"- •' ........... • ":•' : r ß ß }g.' :: ...... -- :: • ß :... - . ..... : •- -., :: .... •, •,,,.,...........-'• :•, •,... .-•.. . ,. -- • . ..•? .• :, )•:,....•,.: (. • ..... .: . 5 . : •: .,.:. .:.. .• .- .,::.::.. , .... Figure 2.•Distdbufion of s•fhydryl groups in cross section of hair following exposure to thioglycolate lotion but before chemical neutralization (stained with NQ •agent de- scribed in text).

260 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE 3--STABII.ITY OF SOLID DMA AND DMA LOTIONS Sample No. ,--- .•Before Aging----- Free Time Eq. SH Alk. Samples* Aged Wt. M M ß -After Aging--• Free Eq. SH Alk. Wt. M M 1 DMA solid 51/2 months 105.0 105. 2 DMA solid 41/2 years 105.2 106.0 3 (NH4)2 DMA solid 51/2 months 122.6 123.8 4 Na2 DMA solid 51/• months 128.6 129.2 5 (NH02DMA-NH:3 1 year ... 0.46 0.55 ... 0.46 0.54 lotion 6 (NHg)=DMA- 1 year ... 0.47 0.69 ... 0.46 0.70 MIPAt lotion 7 (NH4)=DMA- 1 year ... 0.48 0.66 ... 0 48 0.66 DIPA:J: lotion * Samples were stored in closed bottles at room temperature. • MIPA--monoisopropanol amine. :• DIPA--diisopropanol amine. TABLE 4--POWDERED WAVING COMPOSITIONS FORMULATED WITH DMA Experi- ment No. Curl Level (After 1 Shampoo) Waving Compositions pH CN AO 1 0.50M (NH0=DMA , 0.65M Na2CO:• 9.05 90 120 2 Thioglycolate control 100 115 3 0.4M (NH4)=DMA, 0.2M MgTGA, 0.66M AMP* 9.10 100 4 Thioglycolate control 100 5 0.4M (NH4)2DMA, 0.35M (NHj2SS-TGA,t 0.6M 8.96 85 Na•CO• 6 0.35M Na2DMA, 0.35M Na•SS-TGA, 0.5M AMP 9.30 90 7 0.4M (NH4)aDMA, 0.35M (NH4)aSS-TGA, 0.65M 9.08 90 AMP 8 Thioglycolate control 100 * 2-Amino-2-methyl- 1,3-propanediol. •' SS-TGA = dithiodiglycolate. TABLE 5--THE USE OF IMPREGNATED END PAPERS TOGETHER WITH DMA I,OTIONS ON A CN PROCESS End Paper -----(3•/2 X 2 in.) , Experi- (NH4)2SS- Curl Level ment MgTGA* TGA•' (After 1 No. Lotion Composition Meq. Meq. Shampoo) 1 0.41M (NH4)2DMA NHa to pH 9.28 0 30 ... 115 2 "do" 0.59 120 3 "do" ... 6. •b 1•s 4 "do" 0.90 100 5 "do" R•t lar end paper 80 6 Thioglycolate control Regular end paper 100 * Magnesium thioglycolate. • Ammonium dithiodiglycolate. ++ Average of 2 tresses.