Characterization and analysis of toughened bio‐oil‐based phenolic foam prepared from poplar

Abstract

Different catalysts (NaOH, H 2 O 2 , and NaOH/H 2 O 2 ) was used to catalyze the conversion of poplar to bio-oil, which was then used to synthesize bio-oilbased phenolic foam (BPM). The bio-oil and BPM were characterized with GC-MS, FT-IR, TGA, optical microscope, extreme oxygen index analyzer, and universal testing machine. The results showed that the BPM had the better flame retardancy. The maximum limiting oxygen index was 37.7% found on the BPM prepared from NaOH/H 2 O 2 -catalyzed bio-oil. Compared with NaOH or H 2 O 2 , the NaOH/H 2 O 2 presented synergistic catalysis in producing bio-oil with the highest phenolic content. The BPM synthesized with the bio-oil substitution at 20% showed the maximum compressive strength of 0.27 MPa. After the microscopic observation and TGA, it was found that BPM prepared from NaOH/H 2 O 2 catalyzed bio-oil had more uniform and tiny bubbles, and higher thermal stability. In addition, a reasonable reaction mechanism was provided to explain the role of bio-oil in BPM synthesis.