Methods of Analysis

Nitrogen analysis was provided by Dow Chemical Company using a Leuco HCN Analyzer.

Carboxymethyl content of cellulosic fabrics was determined as follows. Samples were steeped overnight in 0.1% HCl solution at room temperature. These were then washed with distilled water until the wash water showed no presence of chloride by an AgNO3 drop test. Samples were dried at 105oC, then brought to standard conditions. Exactly 0.3 grams of each sample was carefully weighed and combined with 100 mL distilled water and 20 mL of 0.05N NaOH in a beaker. This mixture was titrated with standardized HCl solution to a phenolphthalein end point. The carboxymethyl content was calculated as follows.

mmols carboxymethyl content per 100 grams = 100 * (Vo V) * (NHCl) / (0.3)

where V is the titer for the sample, Vo is the titer for the blank, and NHCl is the normality of the HCl titrant.

Crease angle measurements were made by AATCC Standard Test Method 66, Wrinkle Recovery of Fabrics: Recovery Angle Method. The presented results are the sum of the recovery angle of the tested fabric in the warp and weft directions. Breaking strength was determined with an Instron tensile tester using ASTM test method D1682.

Results and Discussion

The nitrogen content of the treated fabrics are shown in Table II. As expected, the nitrogen content increases as the application level of cationized chitosan increases. Laundering the treated fabrics did not decrease the nitrogen content, indicating that a durable finish was obtained.

 

 

The dry and wet wrinkle recovery angles measured for the treated fabrics are given in Table III and Figures 4 and 5. As can be seen, both recovery angles increase as the carboxymethyl content and the cationized chitosan application level increase. The wet recovery angles in particular show remarkable increases.