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Wool acidic peroxide

In general, the oxidation of linoleic acid was inhibited by the enzyme coupled antioxidant substrates even after a strong washing treatment (WCA and WCHG) in comparison with the control sample. The caffeic acid (CA) and chlorogenic acid (CHG) treated wool samples exhibited potent antioxidant activities with 75.12 % and 54.15 % inhibition of linoleic acid peroxidation, respectively. [Pg.133]

A 500-ml, three-necked, round-bottom flask is fitted with a mechanical stirrer, a thermometer, and a wide-stern (powder) funnel. The flask is cooled in an ice-salt bath and charged with 125 ml (approx. 0.5 mole) of 15% sodium hydroxide solution. When the stirred solution reaches -10°, 30% hydrogen peroxide (57.5 g, 52.5 ml, approx. 0.5 mole) previously cooled to -10° is added in one portion. The pot temperature rises and is allowed to return to —10° whereupon 37.5 g (0.25 mole) of phthalic anhydride (pulverized) is added rapidly with vigorous stirring. Immediately upon dissolution of the anhydride, 125 ml (approx. 0.25 mole) of cooled (-10°) 20% sulfuric acid is added in one portion. (The time interval between dissolution of the anhydride and the addition of the cold sulfuric acid should be minimized.) The solution is filtered through Pyrex wool and extracted with ether (one 250-ml portion followed by three 125-ml portions). The combined ethereal extracts are washed three times with 75-ml portions of 40% aqueous ammonium sulfate and dried over 25 g of anhydrous sodium sulfate for 24 hours under refrigeration. [Pg.154]

When tertiary butyl hydrogen peroxide (TBHP) was used alone as the radical initiator, no grafting of methylmethacrylate (MMA) onto wool was observed. However, TBHP in conjunction with mineral acids, such as H2SO4, HNO3, or HCIO4 afforded good results [26]. Protonation of TBHP by the acid aided in the dissociation of TBHP to yield free radicals, which initiated grafting reaction. [Pg.484]

Oxidative bleaching of wool is invariably carried out with hydrogen peroxide. The active species involved is likely to be the same as on cellulosic substrates but specific reactions with wool amino acid residues must be considered. The primary reaction is oxidation of cystine disulphide bonds leading to the formation of cysteic acid residues (Scheme 10.41). The rupture of disulphide crosslinks, with attendant increase in urea-bisulphite and alkali solubility values, adversely affects fibre properties. As the severity of bleaching conditions increases, the urea-bisulphite solubility remains little changed but the relationships between alkali solubility and cysteic acid (Figure 10.36) and between cystine and cysteic acid (Figure... [Pg.145]

Figure 10.36 Relationship between alkali solubility and cysteic acid content of peroxide-bleached wool [259,261]... Figure 10.36 Relationship between alkali solubility and cysteic acid content of peroxide-bleached wool [259,261]...
The adverse effects of alkali on wool cause reduction in its dry strength only after fiber solubilization and considerable loss in its cystine content (105). Because of its sensitivity to alkali, wool is preferentially given a peroxide bleach with added formic acid silk does not degrade nearly so much under alkaline conditions and may be bleached at pH 10 with peroxide, using stabilizers such as sodium silicate (98). [Pg.200]

Hydrogen peroxide and peroxycarboxylic acids (RCO3H) are normally relatively stable, but as mentioned above they can be rendered unstable by a wide variety of contaminants, particularly at excessively high temperatures. Cleanliness, good housekeeping and proper storage are therefore essential. The major contaminants that cause decomposition are combustible organic materials (e.g. cotton, wool, paper) or metals, particularly transition metals and their salts (Table 1.7).50 Alcohol thermometers or stainless steel thermocouples... [Pg.23]

Bleaching of wool in acidic hydrogen peroxide solution... [Pg.174]

Wool has been successfully bleached with a stable emulsion of hydrogen peroxide [49] or permonosulphuric acid [50] in perchloroethylene. By this means it appears to be possible to obtain the same degree of whiteness as that attainable in a standard aqueous bleach, but more rapidly and with the use of less peroxide. No stabilising or activating agents are needed, but the bleaching of wool in perchloroethylene seems to be more deleterious to mechanical properties of bleached wool than equivalent aqueous procedure. [Pg.178]

Hydrogen peroxide is not suitable for acrylic fibre at highly alkaline condition and moreover acrylic fibre turns yellowish on alkaline peroxide treatment. The discolouration can be improved by after-treatment with formic acid in presence of detergent. Acrylic/wool blends can also be bleached by a reduction bleach or by combination of peroxide and reduction bleaching process. [Pg.208]


See other pages where Wool acidic peroxide is mentioned: [Pg.145]    [Pg.148]    [Pg.327]    [Pg.284]    [Pg.472]    [Pg.810]    [Pg.1]    [Pg.349]    [Pg.141]    [Pg.485]    [Pg.869]    [Pg.810]    [Pg.87]    [Pg.150]    [Pg.161]    [Pg.164]    [Pg.169]    [Pg.158]    [Pg.74]    [Pg.435]    [Pg.810]    [Pg.40]    [Pg.141]    [Pg.127]    [Pg.1236]    [Pg.82]    [Pg.1]    [Pg.199]    [Pg.1265]    [Pg.251]    [Pg.349]    [Pg.93]    [Pg.174]    [Pg.174]    [Pg.174]    [Pg.176]    [Pg.194]    [Pg.333]    [Pg.355]   
See also in sourсe #XX -- [ Pg.174 ]




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