which is indicative of some sort
of electrostatic interactions being established between the hydrophilic ends of the polymer chain segments.
3.1.4. Effect of UV radiation on bleached hair Fig. 4a–c depict the variation of s3, I3, and Fv respectively of bleached hair with UV exposure time. Comparison of these graphs with those for UV exposed virgin hair (Fig. 1a–c) shows distinct dif- ferences in the response of the two samples towards UV influence. Initial swelling of the fiber is not seen in the ‘bleached + UV irradi- ated’ hair, instead, the value of s3 decreases right from the begin- ning and reaches its minimum value, dropping by about 230 ps, in just 200 h of irradiation time i.e. only about one-third of the time needed in the case of virgin hair. Thus, here also, cross-linking forces the polymer segments to come closer and this effect
Fig. 2. Effect of humidification and bleaching on o-Ps lifetime s3 and intensity I3 of UV irradiated virgin hair sample. Here, UV200h represents a 200h UV irradiated hair; UV200hW is a 200h UV exposed + humidified hair; UV800hB is a 800h UV exposed + bleached (1h) hair.
Fig. 3. Variation of (a) o-Ps lifetime s3 (free volume hole size Vf), (b) o-Ps intensity I3, and (c) fractional free volume Fv as a function of bleaching time.
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which is indicative of some sort
of electrostatic interactions being established between the hydrophilic ends of the polymer chain segments.
3.1.4. Effect of UV radiation on bleached hair Fig. 4a–c depict the variation of s3, I3, and Fv respectively of bleached hair with UV exposure time. Comparison of these graphs with those for UV exposed virgin hair (Fig. 1a–c) shows distinct dif- ferences in the response of the two samples towards UV influence. Initial swelling of the fiber is not seen in the ‘bleached + UV irradi- ated’ hair, instead, the value of s3 decreases right from the begin- ning and reaches its minimum value, dropping by about 230 ps, in just 200 h of irradiation time i.e. only about one-third of the time needed in the case of virgin hair. Thus, here also, cross-linking forces the polymer segments to come closer and this effect
Fig. 2. Effect of humidification and bleaching on o-Ps lifetime s3 and intensity I3 of UV irradiated virgin hair sample. Here, UV200h represents a 200h UV irradiated hair; UV200hW is a 200h UV exposed + humidified hair; UV800hB is a 800h UV exposed + bleached (1h) hair.
Fig. 3. Variation of (a) o-Ps lifetime s3 (free volume hole size Vf), (b) o-Ps intensity I3, and (c) fractional free volume Fv as a function of bleaching time.
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