Enhanced photostability and thermal stability of wood by benzoylation in an ionic liquid system

To enhance the compatibility and photostability of wood with hydrophobic polymers for photostable green composites production, wood meal was dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and homogeneously benzoylated with benzoyl chloride in the presence of triethylamine as a neutralizer. The effects of various reaction parameters on the properties of the benzoylated wood were investigated. The weight percentage gain (WPG) was arranged from 29.6% to 118.1%. The physicochemical properties of the benzoylated wood were characterized by FT-IR, solid-state CP/MAS 13C NMR, solution-state 1H and 13C NMR, TGA/DTG, as well as artificial accelerated weathering. The results confirmed that the homogeneous benzoylation was successfully conducted and highly benzoylated wood derivatives could be obtained in this novel system. The thermal stability of the benzoylated wood was increased while the WPG value above 40.0% and decreased with a low WPG value. The wood meal became more hydrophobic after benzoylation. A linear relationship between the WPG value and the photostability of the benzoylated wood prepared in the ionic liquid system was observed for the first time. Benzoylation of wood to high weight gains was effective at protecting wood from photodegradation. All of these improved properties make it beneficial for photostable green composites production.

Highly benzoylated wood was successfully synthesized in ionic liquid system. The improved hydrophobic property, thermal property, and photostability of the benzoylated wood make it beneficial for photostable green composites production.Figure optionsDownload as PowerPoint slideHighlights
► Wood meal was homogeneously benzoylated with benzoyl chloride in [C4mim]Cl.
► The benzoylated wood with WPG between 9.6% and 118.1% were accessible.
► Photostability of the benzoylated wood linearly correlated with WPG value.
► The benzoylated wood with a high WPG value shows good photostability.