| abstract |
Carboxymethylated cellulosic articles having degree of substitution in the range from 0.12 to 0.35 and in which the carboxymethyl groups are believed to be predominantly within the amorphous regions to the exclusion of the crystalline regions have usefully non-adherent properties as wound dressings. Such wound dressings may be made by carboxymethylating a cellulose fabric so that its absorbency is little greater after carboxymethylation than beforehand and the degree of substitution is as stated above. Carboxymethylation can be carried out by contacting cellulose II fibers or other articles with a solution containing sodium hydroxide, sodium chloroacetate, water and ethanol. The solution may contain from 4 to 8 percent by weight sodium hydroxide and from 50 to 60 percent by weight water (including water in the fibre) or the weight ratio of sodium hydroxide to water (including water in the article) may be from 0.095 to 0.115 and the weight ratio of cellulose in the article to water (including water in the article) may be from 0.22 to 0.28. |