Open Collections

Liang, Yalan

University of British Columbia

Arabinose side chains significantly influence the crystallization and functional properties of xylan particles derived from esparto grass. By applying oxalic acid as a selective debranching agent, we observed that the removal of arabinose profoundly affected molecular weight, thermal stability, and crystallinity of xylan. Monosaccharide analysis showed that extended oxalic acid pretreatment progressively reduced arabinose content, achieving 65.7% removal after 72 hours. Gel permeation chromatography (GPC) revealed a marked decrease in molecular weight from 6.96 kDa in untreated xylan (BX) to 3.83 kDa after 72 hours of treatment. Thermogravimetric analysis (TGA) indicated that thermal stability remained nearly unchanged. Furthermore, 13C NMR analysis confirmed the stepwise elimination of arabinose, facilitating increased crystallinity as confirmed by XRD and AFM. These findings clarify arabinose's role in xylan crystallization and offer insights for tailoring xylan-based materials for functional applications. Building upon the side chain effects of crystallization and morphology changes of xylan particles, post-crystallization physical treatments have not been explored in the current literature although it has shown significant impact to cellulose nanocrystals. This works examines how low temperature exposure fundamentally alters the supramolecular organization of xylan hydrate crystals. Additionally, controlled high humidity drying (93% relative humidity) emerged as a critical factor influencing surface smoothness and homogeneity of xylan particles during sample preparation. These findings are essential for understanding the structure and property changes of xylan particles through different duration of pretreatment, freezing temperature and high humidity drying process. These investigations enhance our comprehension of structure-property relationships in materials derived from xylan. By clarifying how arabinose side chains influence crystallization processes, the work uncovered novel routes for creating functional materials with altered properties, specifically producing larger xylan particles with higher crystallinity when side chains are removed. Additionally, our findings on post-crystallization treatment conditions deliver pragmatic methods for precisely controlling particle morphology to suit targeted applications.

Text

2025-04-23

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90738

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/