POLYMER DEPOSITION IN HAIR Table II Effect of pH on Pretreament of Hair with THP (0.1M) on Polymerization of Methacrylamide in hair in 0.01/V H2SO4 at 25øC, Liquor:Hair Ratio of 50:1 [NAN] = 50 gl-• [K2S208] = 3 gl-1 time = 60 rain 545 pH of Pretreatment Polymer Deposit (%) 1.3 62.8 2.2 81.6 4.1 78.4 5.2 71.0 7.O 85.8 9.2 82.6 Table III Effect of Rinsing Time on Subsequent Preferential Polymerization of Methacrylamide at 25øC in Pretreated Hair [MAN] = 50 gl-1 [K2S208] = 3 gl-1 time = 60 rain Polymer Deposit after Rinsing of Pretreated Hair for Pretreatment 1 min 5 min 60 rain 2M NaHSOa at 35øC for 30 min 26.6 12.5 1.8 0.5M TGA at pH 5.2 and 35øC for 30 min 18.6 ... 4.9 0.252}/THPC at pH 5.2 and 35øC for 30 min 34.5 33.0 32.5 Table IV Effect of Time on Pretreatment with THPC on Polymerization of Methacrylamide in Hair in 0.01N HsSO4 at 25øC using Liquor:Hair Ratio of 50:1 [NAN] = 50 gl-• [KsSsOs] = 3 gl-1 time = 60 min Time of Pretreatment (min) Polymer Deposit (%) 5 5.3 10 12.6 20 30.0 30 49.8 4O 66.5 the pretreatment was investigated, the results being given in Table VI. The data collected so far provided a basis on which standard condi- tions of pretreatment were defined. These consist ooe treating 1 g ooe hair with 20 ml of 0.2M THPC in acetate buffer (pH 5.2) for 30 minutes at 40 øC, and were adopted for further work on polymerization of meth- acrylamide in hair.

546 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table V Effect of Temperature of Pretreatment with THPC on Polymerization of Methacrylamide in Hair in 0.01N H2SO4 at 25øC using Liquor: Hair Ratio of 50:1 IMAM] = 50 gl-1 [K2SsOs] = 3 gl-X time = 60 rain Temperature of Pretreatment (øC) Poly•ner Deposit (%) 20.0 17.5 29.0 23.0 33.5 30.4 36.8 39.8 40.0 50.1 Table VI Effect of Various Liquor:Hair Ratios in Pretreatment with THPC on Polymerization of Methacrylamide in Hair in 0.01N HsSO4 at 25øC using Liquor: Hair Ratio of 50:1 IMAM] = 50 gl-X [K,•SsOs] = 3 gl-X time = 60 rain Liquor: Hair Ratio Polymer Deposit (%) 5:1 37.8 10:1 44.5 20:1 49.8 50:1 50.7 Effect IMAM] Table VIi of pH on Polymerization of Methacrylamide in THPC-treated Hair at 25øC = 50 gl-1 IK:S2Os] = 3 gl-1 time = 60 rain pH Polymer Deposit (%) 1.2 48.4 2.2 50.4 3.6 46.4 5.2 30.2 6.0 23.8 7.0 8.2 9.2 2.4 Polymerization One of the first aspects to be studied was the effect of pH on the rate of polymer deposition (Table VII and Fig. 2).