Studies on the effect of additives concentrations on synthesis and characterization of furan-lignin foams

Abstract

Bio-based foams are growing and promising materials to replace petroleum-based foams because of their beneficial qualities including their affordability, outstanding fire resistance, high thermal insulation performance, eco-friendliness and the bio-sourced origin of the feedstock components. This study produced rigid bio-based foams using chemicals derived from plants, primarily from furfuryl alcohol and polyol derived from lignin. Lignin-based polyol and furfuryl alcohol were used to produce furan-lignin foams, which are free of formaldehyde and ozone damaging substances. Seven different furan-lignin foams were produced by substituting the toxic formaldehyde with a more eco-friendly glyoxal as a hardener while using diethyl ether and bentonite as blowing agent and filler respectively. Effects of these reagents on the quality of foams produced were assessed by varying their contents in the formulations. The properties of the produced bio-based foams such as compressive resistance, water absorption capacity, density and moisture content were evaluated. Further product characterizations: elemental composition, thermo-gravimetric analysis, Fourier transforms infrared spectroscopy and Scanning electron microscopy were carried out on the foams. The reaction leading to foam production was spontaneous at room temperature with an acid catalyst. Results showed that the concentrations of the blowing agent, hardener and filler, all had effects on the quality of the bio-based foams produced. Scanning electron microscopy results showed that the foams possessed closed cell morphologies, a rigid foam characteristic for good thermal and acoustic performance but modest water absorption, with cell widths of 10–200 μm, having high densities and strong compressive strengths as inherent characteristics. The results of the characterization indicated that the foams may be used as a thermal barrier or a support in construction and packaging applications because they had strong thermal stability, high compressive strengths, and a modest capacity to absorb water.