Enthalpies of interaction of cellulose derivatives with starch

The enthalpies of dissolution of methylcellulose-starch and sodium carboxym ethyl cellulose-starch mixtures were measured at 298 K. Dissolution of mixt ures in water is accompanied by the emergence of an exothermic effect, the value of which depends on the mixture composition. Based on these data, the enthalpies of interaction of the mixture components were calculated within the entire interval of compositions. It was shown that for the sodium carb oxymethyl cellulose-starch mixture, the enthalpy of interaction is negative over the entire range of starch concentrations. For the methylcellulose-st arch system, the enthalpy of interaction is negative at low concentrations of starch (0.3-0.5) and positive when the concentration of starch is high. The experimental evidence is interpreted from the viewpoint of starch compa tibility with the derivatives of cellulose.