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Fire hazard of phosphorus-containing hard casting polyurethane foams

Introduction. Fire-safe rigid filling polyurethane foams (PUF), meant for low-temperature thermal insulation of pipelines and technological equipment were developed. The effect of concentration of oxyethylated tetraalkylphosphonate pentaerythritol (phostetrol-1) on technological, physico-mechanical and thermal properties, contents of pyrolysis products and main fire hazard indicators of PUFs was explored. The effect of chemical nature and metal compounds concentration of variable valence on fume-generation ability of phosphorous-containing PUFs was examined. Main technological and physico-mechanical properties and fire hazard indicators of developed styrofoams are provided. Materials and methods. Rigid filling PUFs were obtained on the basis of simple oxyethylated polyols and polyisocyanate. Phostetrol-1 was used as a reactive phosphorous-containing compound. As a foaming and hardening catalyst of developed PUF’s a nitrogen-containing polyol (mark Lapromol 294) and dimethylethanolamine was used, and as a foaming agent - mixture of freon - 11 and water. Different metal compounds of variable valence were used to reduce fume-generation ability and toxicity of pyrolysis products of rigid phosphorous-containing PUFs. Thermal properties of examined PUFs were studied with the help of thermoanalytical complex Du PONT 9000. Main technological and physico-mechanical properties and fire hazard indicators of styrofoams were determined under existing GOSTs. Results. The effect of phostetrol-1 concentration in polyester compound on main technological and physico-mechanical properties, contents of pyrolysis products and main fire hazard indicators of rigid filling PUFs was established. It is shown that to obtain moderately flammable PUFs the phosphorous concentration in styrofoam must exceed 2.5 mass. %. The correlation between low-scale evaluation methods of flammability of rigid PUFs was found. The effect of phosphorous concentration on fume-generation ability and contents of pyrolysis products of rigid PUFs was found. The effect of chemical nature and metal compounds concentration of variable valence on fume-generation ability of phosphorous-containing PUFs was examined. It is shown that effective decrease of fume-generation ability and toxicity of pyrolysis products of moderately flammable PUFs occurs when Cu2O or chrome spinels are introduced to the polyester compound. Conclusions. As a result of conducted research it was established that the combined use of phostetrol-1, Cu2O and chrome spinels makes it possible to obtain rigid fire-safe PUFs with high physico-mechanical properties. Fire-safe rigid filling PUFs, developed with the use of raw native materials, are recommended to be used for low-temperature thermal insulation of pipelines and technological equipment.