Contribution to assessing cross-linking of protein hydrolyzate with diepoxides

This work summarizes the influence exerted on cross-linking of protein hydrolysate obtained through enzymatic hydrolysis of chrome-tanned leather shavings, by means of diepoxides (1,2:3,4 diepoxybutane and 1,2:7,8 diepoxyoctane). Attention was given to preparation of cross-linked samples, their solubility, intrinsic viscosity and IR spectra. Suitable conditions for cross-linking were found at pH = 9 and 25°C temperature. Solubility of samples decreased proportionately with increasing concentrations of cross-linking agent. Viscosity measurements yielded best results in 1M KCl solution. Determining intrinsic viscosity indices proved this value was influenced more by the approach of the gelation point than by the epoxide content. IR spectra demonstrated that in the region ofwave numbers 838, 912 and 1,250 cm -1 , peaks of epoxide groups of employed pure cross-linking agents coincide with similar peaks of other groups of cross-linked samples; peaks of epoxide bonds at the mentioned wave numbers are discernible only with highest employed concentrations of cross-linking agents. Future research will address examining various epoxy groups, employing di- or multifunctional amines and determining critical gelation conversions and critical stoichiometric ratios of defined substances.