Abstract:

The interconnected pore network within wood is the main way of water migration and chemical penetration, which plays a decisive role in wood drying, wood impregnation and modification, and is also an important factor to affect the functional properties of wooden products, such as sound absorption, thermal insulation and humidity control. However, at present the main evaluation indexes of wood pore structure are porosity, pore size distribution, pore volume, density, specific surface area, pore morphology and fractal dimension, etc., and no comprehensive and systematic studies have been carried out on the evaluation of pore connectivity. In this paper, the research on the evaluation of wood pore structure and pore connectivity with three types of pore characterization techniques, those are the adsorption analysis method, the nuclear magnetic resonance method as well as the computed tomography three-dimensional imaging method, is reviewed and summarized. Furthermore, scientific problems and prospects are proposed as follows: 1) Construction of wood pore connectivity evaluation system: firstly, to form the evaluation theory basis and research method of wood pore connectivity, that is to evaluate and verify the applicability and accuracy of existing methods, and further modify the theoretical model and optimize the corresponding evaluation method based on wood pore characteristics. Secondly, to facilitate the research on the evaluation scope and evaluation index quantification by combination and complementarity of various characterization technologies for the integrity and comprehensiveness of wood pore connectivity evaluation system. 2) Interpretation of the topological structure of wood pore space: the pore space of wood is a very complex internal topological structure with different pore distributions and pore connectivities in the longitudinal, radial and tangential directions, and greatly distinct pore sizes as well as diverse morphologies which are cross-linked differently. The evaluation of wood pore connectivity will provide a wider perspective on the interpretation of wood pore topological structure. On the basis of the full refining of the characteristic index parameters, and combined with data mining technology, the wood pore topological structure will be comprehensively interpreted through deep analysis for the potential relationships and rules of the characteristic index data, so as to promote the upgrading and optimization of the traditional characterization technology and evaluation system.

Key words: wood, pore stucture, pore connectivity, pore characterization technique