WOOD RESEARCH Volume 68, Number 4, 2023
Xiaoyan Zhang, Lanxing Du, and Sijin Li

Stepwise Extraction of Hemicelluloses with Water and Alkali from Larch Wood and their Sugar Compositions

The aim of the present study was to isolate hemicelluloses by stepwise extraction with water and alkali from larch (Larix principis-rupprechtii Mayr) sapwood and heartwood. One water-soluble arabinogalactan (AG) and three alkali-soluble hemicelluloses- arabinoglucuronoxylan (AGX), galactoglucomannan (GGM) and glucomannan (GM) were obtained. The yield of AG extracted with hot-water from larch heartwood was 7.57%, it was 17.96% in total of three alkali-extracted hemicelluloses. There was no significant difference in the yield of hemicelluloses from sapwood and heartwood. Monosaccharide compositions of the hemicelluloses were determined by high performance liquid chromatography after acid hydrolysis. The results showed that galactose and mannose were the main glycosyl units of hemicellulose, followed by xylose. Galactose mainly derived from AG, whereas mannose and xylose originated from alkali-extracted hemicelluloses.

WOOD RESEARCH Volume 63, Number 1, 2018
Nadir Ayrilmis, Ali Gürel, Mehmet Özdemir, and Tolga Kapti

Bond performance of formaldehyde-based resins synthesized with condensate generated during kiln-drying step of wood

This research investigated the potential use of condensate generated during vacuum drying with high frequency of wood in the synthesis of urea-formaldehde (UF) and melamineformaldehyde (MUF) resins. The liquid condensate (5 wt%) of total resin composition) of walnut, beech or oak was replaced with deionized water used in the synthesis of UF and MUF resins. The condensate did not affect the properties of the UF and MUF resins in terms of density, solid content, viscosity, pH, and gel time as compared with the control resins. The control UF and MUF resins did not show a significant difference with the bond strength of UF and MUF resins at dry and wet conditions, except for the oak-UF resin. As for the dry condition, the control resin had the highest bond strength with a value of 12.9 N. mm-2, followed by beech-UF resin (12.6 N. mm-2), walnut-UF resin (12.1 N. mm-2), and oak-UF resin (11.8 N. mm-2), respectively. A similar trend was observed for the wet condition. All the modified UF and MUF resins complied with the minimum requirements of EN 12765 standard at dry and wet conditions. The results of this research can be useful for environmentally friend solution of the waste condensate discarded to the ground water.