Distribution and Migration of Moisture in Round Bamboo in Response to Microwave Drying

Abstract

Characterized by its light weight, high strength, and good flexibility, round bamboo is a natural functional biomaterial with a multi-level structure. Cracking is a key factor hindering its wider application. Moisture changes cause cracking when the round bamboo is dried. Therefore, studying moisture variations in the drying process of round bamboo can effectively reduce or solve the cracking problem. In this study, microwave drying with computer tomography (CT) imaging technology was used to understand the distribution and migration of moisture in round bamboo in the course of drying. The results indicated that water content has a significant correlation with the CT value, which can be used to achieve rapid determination of water content. The radial water content of samples gradually decreased from bamboo green (outer) to bamboo yellow (inner). The axial water content was high in the middle and low on both ends. As the water content decreased, the axial moisture distribution was consistent. The internode moisture mainly moved from the junction of bamboo yellow and bamboo partition, entered the adjacent cavity, and then gradually moved outward. Thus, the microwave drying method can effectively achieve industrial drying of round bamboo and prevent cracking.