Preparation and intrinsical flame resistance of reed-based polyurethane foam modified by 9,10-dihydro-9-oxa-10 phosphaphenanthrene 10-oxide

Abstract

The production of polyurethane foam (PUF) from green and sustainable agricultural waste reeds could replace traditional petroleum-based PUF. In this paper, reed naturally contains nano-SiO₂.was liquefied to reed-based polyol (R-P) using Castor oil and PEG-400 as a compound solvent and H₂SO₄ as a catalyst, The liquefaction efficiency is as high as 97.16%; Reed-based polyurethane foam (R-PUF) was prepared with R-P, water, and isocyanate by one-pot and free rise method. Moreover, DOPO with a rigid ring and Phosphorus was introduced into the cross-linked structure of rigid PUF as a reactive-type flame retardant. The mechanical properties, microstructure, thermal stability, and flame retardance of the R-PUFs were investigated, The results showed that the density of R-PUF was 33.03 kg/m³, the thermal conductivity was 0.0350 W/(m·K), and the limiting oxygen index (LOI) was 20.5%, which was higher than petroleum-based polyurethane; the 6%-DOPO PUF has better flame retardant and thermal stability. The mechanism of R-PUF added DOPO is intrinsic flame retardant and the result of the presence of the gas phase inhibiting the combustion chain reaction and the coalescence phase blocking the transfer of oxygen and heat to the interior of the foam.