The present invention relates to an improved method for impregnating a porous material, such as wood, more specifically a method in which an active ingredient to be deposited within the porous material is dissolved in condensed carbon dioxide and impregnated in the material

Methods for producing structural materials from lumber are provided. The methods use an oxygen pre-treatment or a carbonate pre-treatment followed by densification via thermal compression to produce structural materials with strong mechanical properties. The pre-treatments are able to partially delignify the lumber without substantially adversely affecting the mechanical properties of the subsequently densified wood.

The invention relates to a process for treating a lignocellulosic material, preferably wood, comprising the following steps: (1) soaking of the material with organic fluid in order to dissolve at least 40% and at most 85%, in weight %, of the lignin of the material; (2) washing with organic fluid so as to discharge the dissolved lignin; (3) filling with a filling compound; and (4) finishing, so as to obtain a composite formed of a three-dimensional network of transformed filling compound incorporated into a cellulose and lignin network. The invention also relates to a composite structure able to be obtained in this way, and to any part comprising at least one such structure.

The invention relates to a process for treating a lignocellulosic material, preferably wood, comprising the following steps: (1) soaking of the material with organic fluid in order to dissolve at least 40% and at most 85%, in weight %, of the lignin of the material; (2) washing with organic fluid so as to discharge the dissolved lignin; (3) filling with a filling compound; and (4) finishing, so as to obtain a composite formed of a three-dimensional network of transformed filling compound incorporated into a cellulose and lignin network. The invention also relates to a composite structure able to be obtained in this way, and to any part comprising at least one such structure.