An ECF-bleached softwood kraft pulp was placed in contact with a solution of a commercially available carboxymethyl cellulose (CMC) at 80degreesC in 0.05 M CaCl2 for two hours. Under such conditions, part of the CMC becomes irreversibly attached to the surface of fibres. The CMC-modified fibres were then placed in contact with a polyamide-amine epichlorohydrin resin (PAAE), made into paper sheets and cured in an oven. The results show that there is a very strong synergistic action between fibres treated in this way and the PAAE-resin with regard to the wet-strengthening effect of the resin. The synergistic effects were attributed both to the increased amount of PAAE-resin adsorbed by the CMC attachment and to the chemical reaction between the resin and the attached CMC.
- surface modification
- cellulosic fibres
- carboxymethyl cellulose (CMC)
- wet strength resin
- wet strength