Swelling Pressure and Form Stability of Cellular Wood Material
¹Latvia University of Life Sciences and Technologies, Forest faculty, Department of Wood Processing, Dobeles iela 41, LV-3001 Jelgava, Latvia
²Forest and Wood Products Research and Development Institute, Dobeles iela 41, LV-3001 Jelgava, Latvia
Cellular Wood Material (hereinafter CWM) middle layer of the Dendrolight® has been developed in the beginning of this century as a wood material for minimization of internal stresses, because of the material structure and reduced swelling and shrinking impact to products in end use application. Some research has been conducted on the physical – mechanical and physical – chemical properties of CWM, while dimensional stability has not been well researched. The goal of this research is to perform an assessment of the CWM shrinkage and swelling impact on dimensional characteristics of the CWM multilayer composite materials. CWM swelling pressure in length, width, and height of the material were determined and compared to the relevant indicators of pine solid wood. The form stability or the impact of combination of the CWM with some facing materials – wood particle board, medium density fibre board (hereinafter MDF), oriented strand board (hereinafter OSB), pine solid wood, gypsum plaster board used in wood products was investigated. The hypothesis that swelling pressure of CWM must be lower than that of pine solid wood was proved, it is 2.3 times lower in the radial direction and 3.9 times lower in tangential direction compared to pine solid wood. The CWM samples, manufactured for determining the form stability in wetting conditions deflected in the height direction by 4%, thus creating deflections also in the seams between separate lamellas of the CWM. Swelling pressure of the CWM is several times smaller than that of solid wood and can be further limited by creating complex wood and non-wood composite material panels using gluing technique.