Degradation of Polyfurfuryl Alcohol-Based Biopolymer by Soil-Burial and Photo-Degradation Methods

Recently, polyfurfuryl alcohol (PFA) based material has been gaining attention. Despite its use as an intermediate in various industries, the degradation process of PFA has rarely been reported. In this study, neat PFA (PF) and polylactic acid (PLA) incorporated PFA (PF-PL) based thermoset biopolymers were prepared by casting method. The degradation of the prepared biopolymer specimens was carried out under environmental conditions via soil-burial test and photo-degradation method for 21-months. The extent of degradation of PF and PF-PL was assessed by evaluating weight loss, variation in mechanical properties and change in complex viscosity. Structural and morphological changes of degraded PF and PF-PL samples were evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. Weight loss percentage in case of photo-degraded samples was found to be much higher compared to soil buried specimens. SEM micrographs showed a blistered surface and visible cracks on the surface of soil buried and photo-degraded samples, respectively. FTIR spectra of photo-degraded samples showed a new peak at 673 cm−1 indicating the furan ring opening during the degradation process. Significant variation in mechanical properties of PF and PF-PL specimens after soil-burial test also indicated biodegradable nature of the biopolymers. Approximately 45% and 63% of loss in tensile strength was obtained in PF and PF-PL soil buried specimens, respectively. Complex viscosity was lowest for PF and PF-PL samples after 21 months of degradation compared to undegraded specimens thus indirectly indicating the decrease in molecular weight after degradation. All the obtained data revealed the fragmentation of biopolymers, hence supporting the biodegradable nature of PFA-based biopolymer.