Modifying wood with bio-polyesters: analysis and performance

Oligomers of lactic and glycolic acid (OLA, OGA) and poly(butylene succinate/adipate) (OBS, OBA) were impregnated and heated into wood for dimensional stabilisation. These bio-polyesters variously provide bulking and lumen filling treatments. Solvent extraction of treated wood showed that ca. 50% of the polymer remains in wood with in situ polymerisation evidenced by GPC. OGA readily penetrates the wood cell wall, which occurred only on heating OLA, whereas OBS/OBA was lumen filling with any cell wall penetration only evident after water soaking. Stability of OLA/OGA treated wood was improved, but did not withstand extended leaching, whereas OBS/OBA treated wood presented higher stability once leached. Bending resistance was influenced by OLA/OGA treatments, but original MOE values were recovered after leaching. Overall, the results show the bio-polyester treatment can confer specific properties of the modified wood to suit selected end use applications.