Synthesis and Characterization of Xylan Grafted with Polyethylene Glycol in Ionic Liquid and Their Use as Moisture-Absorption/Retention Biomaterials

The objective of this study is to broaden the application of xylan as moisture-absorption/retention biomaterials by grafting polyethylene glycol (PEG) on xylan backbone. Ionic liquid 1-allyl-3-methylimidazolium chloride ([Amim]Cl) and 4,4-diphenylmethane diisocyanate are used as reaction media and coupling reagent, respectively. FT-IR, 1 H-NMR, and gel permeation chromatography analyses indicate the successful occurrence of the grafting reaction. Thermogravimetric analysis/derivative thermogravimetry indicates that the thermal stability of xylan increases after the grafting of the PEG side chains. With an increase of the degree of substitution of xylan- g -PEG, the molecular weight ( M w ) of PEG side chains (1000 and 5000 g mol −1 ), and the relative humidity of environment, the moisture-absorption/retention ratio of xylan- g -PEG increases. To evaluate the biodegradability/biocompatibility of this promising material, the ratio of biochemical oxygen demand to chemical oxygen demand of xylan- g -PEG and the cytotoxicity are tested on the samples. The results indicate that PEG-modified xylan has great potential as moisture-absorption/retention biomaterials.