MOLECULAR DYNAMICS SIMULATIONS OF FURAN RESIN (POLYFURFURYL ALCOHOL): PREDICTING MECHANICAL PROPERTIES

Furan resins can be used as precursor resin for Carbon-Carbon Composites but has also been used in adhesives, acid/corrosion resistant materials, and as an alternative fuel precursor [15]. This paper contains the most current understanding of the structure of furan resin and a Molecular Dynamics workflow for computationally simulating its polymerization with the 'fix bond/react' command implemented in LAMMPS. The predicted mechanical properties of the polymerized resin are in good agreement with the literature values.

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, structural and morphological change by Fourier transform infrared (FTIR) spectroscopy 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 with visible cracks on the surface of soil buried and photo-degraded samples. 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. All the obtained data revealed the fragmentation of biopolymers, hence supporting the biodegradable nature of PFA-based biopolymer.

Kinetics and Thermodynamics of Methylene Blue Adsorption on Polyfurfuryl Alcohol-Derived Templated Carbon and Activated Carbon from H3PO4-Impregnated Moringa oleifera Seed Hull

This work probes the kinetics and thermodynamics of adsorption of methylene blue (MB) from aqueous phase on a templated carbon (TC) synthesized from polyfurfuryl alcohol using kaolinite template at 773 K; and activated carbon produced by the pyrolysis of H3PO4-impregnated Moringa oleifera seed hull (MOSH) at 723 K. Factors such as initial concentration of MB (1-3 mg/50 mL), reaction time (0-60 min.) and temperature (302-328 K) for the process were investigated using isotherms, sorption kinetics and thermodynamics. From the results obtained, adsorption of MB on TC fits both Langmuir and Freundlich isotherms well. The Langmuir isotherm describes adsorption of MB on the activated carbon from MOSH (MOSHC) better than the Freundlich isotherm. The adsorption capacities of the active carbons observed for MB were 29.3 mg/g for TC and 29.8 mg/g for MOSHC. The thermodynamic values evaluated: (14.15 kJ/mol. and 11.48 kJ/mol.), (87.93 kJ/mol. K and 49.55 kJ/mol. K) and (7.10 kJ/mol. and 14.26 kJ/mol.) for TC and MOSHC respectively, indicate endothermic and physical nature of adsorption, and enhanced randomness at the adsorbate-adsorbent interface. The sticking probability ( ) values (3.25 x 10–3 and 1.36 x 10–4 for TC and MOSHC respectively) show that the probability of MB molecules sticking on the surfaces of these active carbons is very high, with that for MOSHC being higher. Negative values (– 12.28 to – 14.68 kJ/mol.K and – 3.56 to – 4.92 kJ/mol.K) for TC and MOSHC respectively, at 302–328 K confirms a spontaneous adsorption process dominated by physisorption. Adsorption of MB on TC supports multilayer formation and was dominated by pseudo-second order kinetics while its adsorption on MOSHC was dominated by pseudo-first order kinetics with a single MB molecule occupying more than one active site. MOSHC, the low-cost adsorbent prepared, is thus very assuring for the removal of organic pollutants like MB from aqueous systems.