A super strong and tough densified wood structure is formed by subjecting a cellulose-based natural wood material to a chemical treatment that partially removes lignin therefrom. The treated wood retains lumina of the natural wood, with cellulose nanofibers of cell walls being aligned. The treated wood is then pressed in a direction crossing the direction in which the lumina extend, such that the lumina collapse and any residual fluid within the wood is removed. As a result, the cell walls become entangled and hydrogen bonds are formed between adjacent cellulose nanofibers, thereby improving the strength and toughness of the wood among other mechanical properties. By further modifying, manipulating, or machining the densified wood, it can be adapted to various applications.

A piece of plant material (e.g., wood) can have a lignin content in a range of 5-16 wt %, inclusive, and a microstructure including native lumina bounded by cellulose-based cell walls extending in a first direction. The piece of plant material can be pressed along a second direction crossing the first direction, such that the lumina collapse and facing portions of the collapsed lumina are brought into contact with each other. The piece of plant material prior to the pressing can have a first density. After the pressing, the piece of plant material can have a second density greater than the first density, for example, at least 1 g/cm.sup.3.

A stable, low pH aqueous silicate suspension is disclosed for modifying wood article(s). The suspension includes: a metal silicate having a solution concentration of from 1.5 wt % to 52 wt % and characterized by a modulus of from about 1.8 to about 4.0; at least one of a protic acid solution and a buffering acid solution in an amount effective to acidify the metal silicate to a pH of 3.0 or less, preferably to a pH between 1.0 and 3.0; and a multivalent metal salt having a solution concentration from 5 wt % to 25 wt %. The suspension has a pH of 3.0 or less. Wood articles impregnated with the suspension and processes for modifying wood articles with the suspension are also disclosed. The stable, low pH aqueous silicate suspensions provide for an increased depth of impregnation into wood articles as compared with conventional silicate treatments.

Disclosed is a board made from acetylated rubberwood elements and a method for making same. The acetylated rubberwood elements have an acetyl content of at least 17% and/or are prepared by acetylating rubberwood elements using an acetylation agent in the vapour phase. The invention also pertains to acetylated rubberwood elements prepared by using an acetylation agent in the vapour phase.

A method for the modification of wood materials to improve mechanical properties, water resistance and flame retardancy by utilizing a combination of mineralization with infusion and polymerization of biopolymers comprising steps performed in the following specific order: (i) preparing and pre-treating wood materials, (ii) hardening the pre-treated wood boards via the creation and deposition of mineral crystal or metal oxide inside the wood fiber, (iii) washing with water and drying to a moisture content below 20%, (iv) treating the wood for flame resistance, (v) treating the wood for water resistance, (vi) immersing with the first salt solution, and (vii) drying the treated wood board increasing waterproof and fireproof to a moisture content of 10%2% to obtain the modified wood.

A stable, low pH aqueous silicate suspension is disclosed for modifying wood article(s). The suspension includes: a metal silicate having a solution concentration of from 1.5 wt % to 52 wt % and characterized by a modulus of from about 1.8 to about 4.0; at least one of a protic acid solution and a buffering acid solution in an amount effective to acidify the metal silicate to a pH of 3.0 or less, preferably to a pH between 1.0 and 3.0; and a multivalent metal salt having a solution concentration from 5 wt % to 25 wt %. The suspension has a pH of 3.0 or less. Wood articles impregnated with the suspension and processes for modifying wood articles with the suspension are also disclosed. The stable, low pH aqueous silicate suspensions provide for an increased depth of impregnation into wood articles as compared with conventional silicate treatments.

A hydrophobic fluid includes a solvent-based solution of at least one aliphatic and/or aromatic hydrocarbon, with a chain length of C9 to C15 and at least one ether, ester, ketone and/or an alcohol, in particular a non-flammable alcohol. The hydrophobic fluid also has a fluoropolymer, in particular a non-combustible fluoropolymer with a flash point>60 C. in a proportion of 0.1 to 30 wt. %.

Disclosed herein is an environmentally friendly wood protecting method against biological deterioration such as fungal, bacterial and insect damage and non-biological wood deterioration such as weathering. The method comprises contacting a wood material with an aqueous solution of a zirconium salts which is followed by a heat treatment step, providing durable protection of wood against biodegradation and improving several other properties of the treated wood.