Liquor ratio

Lower liquor ratios best, alkali dosing needed... 

To sum up, the optimum conditions for methylmethacrylate grafting onto pulp by the ceric ion redox system can be summarized as follows the grafting is done at 30°C for a 1-h reaction time, using liquor ratio 40 1, acid concentration 1%, initiator concentration 0.1%, and monomer 1 mL/g pulp. 

Cotton linters and viscose grade wood pulp were grafted with acrylamide using the xanthate method. The effects of monomer concentration, reaction time, hydrogen peroxide concentration, reaction temperature, and liquor ratio on the grafting process were studied. Optimum conditions for the grafting reaction were established [26]. 

Figure 7 Effect of KMn04 concentration on the amount of consumed KMn04. Liquor ratio 1 50 t = 30 min T = 50°C.

Figure 8 Effect of acid concentration on the grafting of cotton linters. [KMn04] = 0.06 N [monomer] = 1 mol/g cell liquor ratio 1 50 T = 50°C t = 1 h. (—) Oxalic acid (----) sulfuric acid.

Compared with untreated pulp, a relatively high liquor ratio is necessary to attain maximum graft yield (43.5%) because of the small particle size of the ground pulp. For this reason, ground pulp needs a higher liquor ratio than the untreated pulp to help the mobility of the particles. On the other hand, comparing the graft yield... 

Of samples swollen with ethylene diamine, the graft yield at a 50 1 liquor ratio increases as the concentration of ethylene diamine increases. This is due to the increase of decrystallization of swollen samples, which helps the penetration velocity of the chemicals through the cellulosic chains. Graftability of the samples treated with 100% ethylene diamine is lower that of the sample treated with 75%. This is due to the dissolution of low DP chains and some of the hemicelluloses, which is detectable by the increase in DP of the sample teated with 100% ethylene diamine. 

From the preceding results, it is seen that there is a large difference in graft yield between grafted swollen pulp treated with ethylene diamine and untreated pulp at a liquor ratio of 50 1 at all monomer concentrations. 

Figure 10.28 Effect of temperature on the whiteness index of linen bleached using urea-activated hydrogen peroxide [243], Treated with 7 g/l hydrogen peroxide and 8 g/l urea for 150 min at pH 6 and 50 1 liquor ratio...

Figure 10.35 Effect of pH on the whiteness of starch-sized cotton fabric in a one-stage pretreatment with peracetic acid at a long liquor ratio [255]...

Figure 10.44 Influence of pH value of treatment bath containing a commercial permonosulphate formulation on the rate of reaction with dyed wool at 25 °C and 20 1 liquor ratio [301]...

An AOX-free alternative [316] is impregnation with 4 g/1 hydrogen peroxide, 8 g/1 urea and 2 g/1 nonionic wetting agent, then treatment for 60 minutes at 95 °C, pH 8 and 20 1 liquor ratio [316]. This results in a bleached fabric with excellent wettability and without serious fibre degradation. The urea interacts with hydrogen peroxide to form an unstable complex, which then decomposes to form hydroxyl and perhydroxyl radicals, according to Scheme 10.28 [316]. Urea exhibits undesirable environmental characteristics in some respects, however. 

When the Maillard reaction was evaluated using 10 g/1 glucose for 30 minutes at 90 °C and 20 1 liquor ratio the fibre diameter increased by 3.5% xylose gave an increase almost twice as much but showed some yellowing. In this process accessibility of the fibre for dye molecules is increased, since the glucose molecules penetrate between the peptide chains. The reaction also introduces primary alcoholic groups, making the wool more dyeable with... 

Figure 10.59 Sorption kinetics of micro-emulsion cationic softener formulation at different temperatures on cotton fabric [484], Initial concentration 3 g/kg fibre, liquor ratio 15 1...

Levelling acid dyes and particularly 1 1 metal-complex types generally require an exceptionally low pH in order to promote exhaustion and levelling up to 3% o.w.f. sulphuric acid is most commonly used for levelling acid dyes, although hydrochloric, formic and phosphoric acids are also effective. In the case of conventional 1 1 metal-complex dyes it is essential to use a sufficient excess of acid over and above the typical 4% o.w.f. sulphuric acid normally absorbed by the wool, otherwise there may be a tendency towards tippy dyeings and lower wet fastness. The actual excess required depends on applied depth and liquor ratio [2] typical recommendations are given in Table 12.2. 

For environmental reasons, other attempts have been made to reduce the amount of conventional electrolyte added. Lowering the liquor ratio will in itself reduce the amount of electrolyte required. In one commercially feasible system [72], a range of direct dyes was successfully screened to select members that could be applied efficiently to give 95-100% exhaustion using significantly less electrolyte than usual. Thus at applied depths up to 2-3%, only 2-5 g/1 salt is required navy and black dyeings can be produced with only 7.5-10 g/1 salt compared with the conventional 25 g/1 addition. 

Polyester dyeing method Liquor ratio bod5 (mg/l) COD (mg/l) BOD5 COD Harmful factor ... 

Most commercial carriers are used in the dyebath at concentrations within the range 1-8 g/1 depending on active strength of the carrier concentrate, applied depth, liquor ratio and... 

As might be expected with highly soluble dyes, liquor ratio has a pronounced effect on... 

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