Thermal and photochemical stability of poly(vinyl alcohol)/modified lignin blends

• Published in: Polymer degradation and stability Vol. 91; no. 5; pp. 1192 - 1201
• Main Authors: Fernandes, D.M., Winkler Hechenleitner, A.A., Job, A.E., Radovanocic, E., Gómez Pineda, E.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-05-2006; Elsevier Science
• Subjects: Applied sciences; Blends; Exact sciences and technology; FTIR; Kraft lignin derivative; Lignin and derivatives; Natural polymers; NMR; Physicochemistry of polymers; Poly(vinyl alcohol); SEM; Kraft lignin derivative; NMR; Poly(vinyl alcohol); SEM; Blends; FTIR; Lignin; Polymer blends; Property composition relationship; Experimental study; Esterification; Structure composition relationship; Thermal stability; Intermolecular interaction; Thermal properties; Polyvinylalcohol; Chemical modification; Preparation; Miscibility; Photochemical stability; Thermodynamic properties; Lignin derivatives
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2005.05.024

A kraft lignin derivative (KLD) obtained by reaction with
p-aminobenzoic acid/phthalic anhydride was blended with poly(vinyl alcohol) (PVA) by solution casting from DMSO. PVA and PVA/KLD films were exposed to ultraviolet radiation (24, 48, and 96
h) and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (
1H NMR) spectroscopy, and scanning electron microscopy (SEM). PVA films show a loss of thermal stability due to irradiation. PVA/KLD reveals greater thermal stability than PVA and an increase in thermal stability after irradiation. These results suggest that the incorporation of KLD into PVA provides a gain in thermal and photochemical stability. FTIR,
1H NMR, DSC, and TG results obtained for the blends suggest that intermolecular interactions between PVA and KLD chains are present. SEM micrographs revealed blend miscibility for a KLD blend content of up to 15
wt%, as observed at magnification of 1000 times.