Inverse Gas Chromatography for Determining the Surface Free Energy and Acid-Base Chemical Characteristics of aWater Extracted Hardwood (Acer rubrum)
Hardwood hemicellulose extracts can be used as a feed stock for ethanol plants or for renewable polymer applications. Extraction of Acer rubrum wood strands
withwater at 160◦Cand for 90minutes removed approximately 16% of thewood weight. The extract was composed primarily of acetylated glucuronoxylans (63.9%) and lignin (17.6%). The dispersive surface energy and acid-base surface characteristics for a multicomponent freeze dried mixture of hot water extracted Acer rubrum components was determined by inverse gas chromatography (IGC). The dispersive surface energy of the extract was found to be non-sensitive to thermal variations and has a magnitude of 34.6 ± 0.2 mJ/m2 with a Ka of 0.13 and Kb of 0.46. The maple wood had a regressed surface energy of 42.7 mJ/m2 at 20◦C following extraction, and the surface energy before extraction was 40.4 mJ/m2 at 20◦C. Also, before extraction the Ka and Kb of the red maple were 0.19, 0.92, respectively, and after extraction the Ka and Kb were 0.15 and 1.17. Infrared spectroscopy (IR) was used to characterize the wood surfaces and the IR data correlated to the surface energy values. These findings indicate that the hemicellulose-extract components influence the overall average surface energy of maple wood by lowering the surface energy relative to other surface components.