Wood densification

Wood densification via impregnation and polymerization leads to a competitive material, resistant to biological attack, with high surface hardness and satisfying mechanical properties.

Use of the softened composite to manufacture densified material via impregnation, polymerization and compression would be of high interest in industrial fields as flooring, for instance. Cylindric impregnated samples have been subjected to heating, under loading in a metallic mold. Load has been settled to compress the samples enough to extract the air contained in wood lumens. Compressed and polymerized material consists in cellulosics and lactic acid oligomers only.

Brinell hardness of such composites has been assessed and is summarized in Table 3.

Specimen

HB (MPa)

Beech control

3.9

Compressed beech control

19.9

Non catalysed treated beech sample

5.2

Compressed non catalysed treated beech sample

16.4

Catalysed treated beech sample

4.6

Compressed catalysed treated beech sample

7.8

A strong increase in surface hardness is noticed when samples are compressed. The increase is even more obvious on control non treated wood. But once subjected to moisture, non treated samples are unstable whereas treated samples shape is fixed.