Oxygen propylation of cotton black liquor extract and preparation of polyurethane foam

Cotton black liquor extract was utilized as a raw material. Oxygen propylation was conducted using a micro-magnetic high-pressure reactor, followed by a one-step partial substitution of polyether polyol to prepare polyurethane foam (PUF). The characterization of PUF was conducted using FT-IR, SEM, TGA, CCT horizontal combustion, and degradation testing. The results showed that the phenolic hydroxyl conversion rate of cotton black liquor extract after oxygen propylation modification reached 45.5 % at 150℃. It exhibited good compatibility with isocyanates. The produced PUF presented a well-structured, uniform pore distribution. After combustion, a smooth, continuous carbon layer formed, leading to improved thermal stability. The total weight loss rate was reduced by 7 % compared to traditional polyurethane foam (PU0). The carbonization length in horizontal combustion tests decreased to 0.4 mm compared to PU0, and the degradation rate reached 66.7 %.In the CCT experiment, the pHRR value was reduced to 191.38 kW·m⁻², and the pTHR was reduced to 4.52 MJ m². The incorporation of cotton black liquor extract enhanced the thermal stability, flame retardancy, and degradability of the PUF. It provides a way of thinking for the treatment of cotton black liquor and provides a way of thinking for building flame retardant materials.