Energy needs for drying of PAAm-κC composites prepared with Various κC contents

Abstract

Various polyacrylamide (PAAm) - Kappa Carrageenan (κC) composite gels were prepared from acrylamide (AAm), N,N'-methylenebisacrylamide (BIS) and different κC contents by free radical crosslinking copolymerization in water. Pyranine (P) was introduced as a fluorescence probe, and scattered light, Isc, and fluorescence intensities, I, from these gels were monitored during drying at different temperature. The fluorescence intensity of pyranine increased as drying time is increased for all samples. The behavior of I was quantified using the Stern-Volmer equation with moving boundary diffusion model. Desorption coefficient, D increased as temperature was increased for a given κC content. Supporting gravimetrical and volumetric experiments were also carried out during drying of PAAm-κC composite gels. The energy, ΔE values were measured for the drying processes for each kC content gel by using fluorescence, gravimetrical and volumetric methods, respectively. It is understood that ΔE values increase by increasing κC content, indicating that energy needs for the drying of high κC content gel is larger than low κC content gel.