Capillary and Non‐Capillary Absorption of Wood Evaluated by FT–Raman Spectroscopy and Capillary Rise Method

Abstract

Taking the laser‐based FT–Raman spectroscopy and liquid‐based capillary rise as two methods, the wood absorption at the capillary and non‐capillary are studied and quantitatively evaluated. According to the optical method, the natural capillary has greater absorption ability of about two to three times than that of the non‐capillary for pine wood while this value would be reduced in liquid absorption process due to accompanied Lifshitz–van der Waals and Lewis acid–base interactions. The absorption amount is always greater in the capillary as compared with the non‐capillary due to the former with natural pore structure. The absorption of the non‐polar liquid in wood is linearly with the same slow rate in both the capillary and non‐capillary while the absorbed amount is greater. The absorption of polar liquid in wood is non‐linearly in both the capillary and non‐capillary while the faster rate is in non‐capillary as compared with the capillary, especially the liquid with greater Lewis base component. Results comparison suggest that the wood capillary is greater in the Lewis base component and the non‐capillary is greater in the Lewis acid component.