STRUCTURE AND WET STRENGTH ACTIVITY OF POLYAMINOAMIDE EPICHLOROHYDRINRESINS HAVING AZETIDINIUM FUNCTIONALLY

The wet tensile strength of paper made with polyaminoamide-epichlorohy drin (PAE) was found to depend on the resin's relative equivalent weig ht based on azetidinium, the most reactive cross linking group in the resin. The wet tensile strength of PAE treated paper increased as a fu nction of increasing relative azetidinium equivalent weight for a seri es of PAE resins having different molecular weights and quaternary cha rge densities. This relationship may be used to predict the relative o rder of performance between PAE resins on paper machines. The structur e-activity relationship was observed with wet tensile data from papers made on a pilot fourdrinier paper machine and the same trend was obse rved in commercial papermaking operations. A laboratory handsheet meth od did not distinguish any differences between the PAE resins. The rel ative molecular weights of the resins were determined by size exclusio n chromatography (SEC) and the relative azetidinium content was measur ed by nuclear magnetic resonance (NMR) spectroscopy.