Synergistic effects of graft polymerization and polymer blending on the flexibility of xylan-based films.

To develop functional and sustainable films from xylan-based hemicelluloses, beechwood xylan was firstly modified with p-dioxanone (PDO) through ring-opening graft polymerization (ROGP) and then reinforced by poly(vinyl alcohol) (PVA) to fabricate xylan-graft-poly(p-dioxanone)/PVA (XGP/PVA) ternary composite films. FT-IR spectra proved the existence of intermolecular hydrogen bonding interactions between the hydroxyl groups of XGP and PVA. SEM analysis outlined the good compatibility between the XGP matrix and the PVA filler in blending films. From DSC data, the miscibility between XGP and PVA led to increase in the glass transition temperature (Tg) and the crystallinity (Xc) of XGP. In addition, XRD analysis also revealed the increased Xc of XGP in the presence of PVA, which was consistent with the DSC results. TGA/DTG curves indicated that the addition of PVA improved the thermal stability of XGP. Tensile testing showed a dramatic increase in the elongation at break of films with the development of weight percent gain (WPG) of XGP.