Saminathan Ratnapandian

Equipment

1. Padding mangle, curing chamber and dryer

The equipment described in Sections 3.2.1, 3.2.2 and 3.2.3 were used for padding, curing and drying. The operating conditions were the same as described earlier.

2. Antimicrobial testing

Sterile petri dishes, conical flasks and a thermostat oven were the main equipment utilised for this process.

3. Materials

A bleached and mercerised cotton fabric and the two mordant dyes described in Section
2.2.1.1 and Section 2.2.1.2 were used in this set of experiments. Chemicals listed in Table 2.2 were utilised according to the recipe employed. Chitosan from crab shells (Brookfield viscosity of 200 centipoise and degree of de-acetylation  80%) was sourced from Sigma-Aldrich, Australia and used as received. As bacterial growth media, tryptone soya agar and nutrient broth, both from Oxoids, Australia, were used.

4. Methods

   1. Padding

A 1% stock solution of chitosan was prepared in 1% acetic acid by stirring until a clear solution was obtained. The dissolved chitosan was incorporated into the padding liquor at 0.025%, 0.05%, 0.075% and 0.1% w/v concentrations. In continuation of the work reported in Chapter 3, padding liquor was prepared in accordance with the recipe furnished in Table 5.1. The notable difference was the omission of sodium alginate, because anionic sodium alginate has been reported to form a complex with cationic chitosan and this complex can hinder the dyeing process [182]. Optimal mordant concentrations, 15 g/l for copper (II) sulfate (CuSO₄.5H₂O) and 5 g/l iron (II) sulfate (FeSO₄.7H₂0) as determined in Chapter 3, were used in this phase as well. Freshly prepared dye and mordant solutions were used for all the experiments.

Table 5.1 Padding liquor recipe incorporating chitosan