Two-step hot isostatic pressing densification achieved non-porous fully-densified wood with enhanced physical and mechanical properties

Abstract

A new two-step densification method for wooden materials is proposed. This method achieved wood that was virtually non-porous and fully densified exceeding any value ever reported for a hardwood species. In the first step, the compressive strength of the anatomical wood structure is reduced by delignification, and, in the second, a full densification is achieved by hot isostatic pressing under argon atmosphere. Three tropical hardwood species with distinct anatomical characteristics and properties were used to test the method. The HIP-densified wood's microstructural, chemical, physical, and mechanical properties were assessed. The results indicate that proposed method was effective for all the tested species, obtaining a material that it is mostly non porous, shows homogenous density patterns, preserves the original volume, features great stability and it has enhanced mechanical properties. Therefore, the HIP wood densification may be a promising densification technique since it overcomes several limitations faced by previous wood densification methods.