NDT Applications of Raw Materials for Wood-Plastic Composites and Other Wood Based Products

摘要

The high inhomogeneity of wood causes variation to wood based products and thus wood industries require NDT techniques for the quality control. One way to decrease the variability of the products is to manufacture wood-plastic composites (WPC), which is a fast growing business. NDT methods are still needed to ensure the quality of products. The moisture content of the raw material affects the quality of the end product and it could be adjusted during the manufacturing process. This study is based on electrical impedance spectroscopy (EIS) analyses of WPC and wood based materials. Special emphasis is put on the characterisation of raw materials including WPC granules and wood chips, which are cellulosic raw materials used, e.g., for WPC building materials, pulp and paper. Equivalent circuit models consisting ZARC-Cole elements were developed and the models were fitted to empirical data. Several model parameters and moisture content had very strong relationships. According to the study, EIS has potential for the moisture content analyses based quality control of raw materials for wood-plastic composites.