Bleaching Treatments

With the pulp used, a very low ozone charge did not significantly increase the carbonyl content, since preferably the residual lignin present in the material was attacked by the oxidant [16]. The progressing degradation of the polysaccharide material upon further oxidation, as reflected by the decreasing Mw, is clearly visible in Fig. 8. 

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Yoshimura K, Harii K, Aoyama T, Iga T (2000) Experience with a strong bleaching treatment for skin hyperpigmentation in Orientals. Plast Reconstr Surg 105 1097-1110... 

Oxidation/bleaching Treatment with peracetic acid and/or hydrogen peroxide, or sodium hypochlorite or sodium chlorite, or sulfur dioxide, or potassium permanganate or ammonium persulfate... 

Although gravimetric yield may not be significantly affected by the bleaching treatment, aromaticity as indicated by UV absorption at 280 nm declines by as much as 20%. 

As shown experimentally by Piest [75], cotton which was subjected to various operations, e.g. bleaching, treatment with alkalis or acids, strong heating prior to nitration furnishes nitrocellulose solutions of low viscosity. At the same time an increase in the solubility of the nitrocotton was also observed. This is evidence that the cellulose molecules are shortened and their content of terminal group is increased. A certain proportion of hydrocellulose and oxycellulose may result. The total effect is to bring about an increase in the reductive properties of the cellulose, i.e. an increase of the copper number. 

Water as solvent is good when the use of the so-produced hydrogen peroxide solution is also compatible with the use of water and with the low concentration obtained (typically not more than 1-2 wt%), because the concentration operation is costly and risky. Therefore, for wastewater or some bleaching treatments the methodology could be applied, but for organic syntheses which typically require methanol as the solvent the synthesis in this latter medium is necessary. 

In practice, two types of bleaching process are used, namely the dry-wet and the wet-wet bleaching treatments. In this way, the condition of the... 

Pulps. The spruce thermomechanical pulp (TMP) was obtained from Consolidated Papers Inc., Wisconsin Rapids, Wisconsin. This pulp is sample 4 in Table I. Samples 5, 6, and 7 were the results of various bleaching treatments. 

It has been suggested that quinones are present in milled wood lignins [30]. However, their occurrence in wood and pulps is doubtful. The quinone models studied, 3-methoxy-o-benzoquinone (sample 23) and 2-methoxy-p-benzoquinone (sample 24), did not show any Raman bands when studied using 514.5-nm laser excitation. These compounds were fluorescent and degraded in the laser beam. Nevertheless, such structures, if present, are not expected to survive various bleaching treatments. Quinones are easily attacked chemically and probably do not survive peroxide and borohydride bleaching [19, 31, 32]. 

Instead, when there are peaks, indicating UV absorption, this is a clear indication that the oil has undergone either 1. an oxidation process or 2. a thermal deodorizing or bleaching treatment in the presence of active earth during the refining processes. 

Burgess, H. D. The Degradation of Cellulose in Conservation Bleaching Treatments M.A.C. Thesis, Art Conservation Programme, Queen s Univ., Kingston, Canada, 1979. 

Vi scose/cotton blends can be bleached either by batch method on j ig and winch or by a continuous process using J-Box [150]. Bleaching is done on a winch with sodium hypochlorite (2 g/1 available chlorine) adjusted to pH 10-11 with sodium carbonate, for 1 h at 25°C, or alternatively, with 5 g/1 sodium chlorite adjusted to pH 4 with acetic acid for 30 min at 80°C. Alternatively, the bleaching treatment may follow with alkaline hydrogen peroxide at 85 C. 

Damage factors of s < 0.5 are said to be acceptable after bleaching treatments,... 

After multiple treatments with m-diperisophthalic acid, when bundles of hbers or tresses are allowed to dry, the hbers actually appear glued together, reminiscent of the combined photochemical plus peroxide bleach treatment... 

The objective of these density experiments was not to determine the absolute density of human hair, which is elusive [88], but to determine the relative density of human hair and wool fiber and the influence of damaging cosmetic treatments on this important property. The results of these experiments confirm the conclusions of several others [75, 89] the densities of human hair and wool fiber are similar, and there is no appreciable change in the density of human hair from permanent-waving or bleaching treatments. 

Yoshimura K, Momosawa A, Alba E et al (2003) Clinical trial of bleaching treatment with 10% all trans retinol gel. Dermatol Suig 29 155-160... 

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