The influence of microwave non-thermal effect on leather properties in drying

In order to study the influence of microwave, especially nonthermal effect, on leather properties, the microwave was used to dry leather together with the oven dried leather as a control. The back, butt and belly of dried leathers were tested for mechanical properties, softness, shrinkage temperature, chrome and fat migration, microstructure and dielectric constant. The results showed that microwave could improve the mechanical properties, softness and shrinkage temperature as a visible nonthermal effect. The non-thermal effect could also promote uniformity of chrome tanning agent and fatliquoring agent in leather and strengthen combination of these materials with collagen. In addition, the fiber weaving of microwave dried leather was more orderly and porous proved by SEM and XRD. Furthermore, the dielectric constant of microwave dried leather was higher than control, showing a direct proof of non-thermal effect for microwave. To sum up, Microwave in leather drying has not only thermal effect but also non-thermal effect on improving leather overall performance.