New foaming formulations for production of bio-phenol formaldehyde foams using raw kraft lignin

The submitted work presented new foaming formulations demonstrated for production of bio- phenol formaldehyde (BPF) resins and thermal insulation foams using raw kraft lignin (KL) as a green feedstock, reducing both petroleum-based phenol and formaldehyde by up to 50%. The obtained lignin-based BPF foams exhibited low apparent density (20–80 kg/m³), strong compressive strength (up to 1.01 MPa), excellent thermal conductivity (0.03–0.048 W/m·K) and combustion properties (LOI: 32–33%), and satisfactory closed cell structure, all comparable to commercial phenol formaldehyde (PF) foams. These BPF foams, using KL, can act as flame retardant and insulation materials for construction or retrofitting of buildings, thereby future commercialization of these lignin-derived phenolic foams would lead to cleaner production of flame retardant and insulation materials using forestry and agricultural residues/waste. © 2018 Elsevier Ltd