Study On The Combustion Toxicity Suppression Of Flame-retardant Rigid Polyurethane Foam

The dissertation focuses on suppressing the combustion toxicity of rigid polyurethane foam?RPUF?in which APP/DMMP serve as the flame-retardant system and series of transition metal containing additives as suppressors.Many technologies have been used to study the combustion toxicity of multi-doped RPUF,and have preliminarily explained the suppressors' possible mechanisms for reducing the combustion toxicity.In addition,two hyper-branched flame retardants have been synthesized to replace the APP/DMMP system to flame-retarding RPUF,and further applied to other polymers?PBT,PP?.The research work is divided into four parts.1)Prepared a series of octahedral Cu₂O particles and their hybrids Cu₂O@CNT,Cu₂O@GO by wet chemical method,and introduced them into flame-retardant RPUF system.The Cone results indicated that Cu₂O and its hybrids can reduce the materialsO HRR and SPR.The Smoke Box testing told that Cu₂O and its hybrids can suppress the bad effect on smoke production of APP/DMMP,and able to bear comparison with the pure RPUF.In the FTTP test,825? was better than 650 ? to enable the suppressors to perform well.TG-IR results indicated that Cu₂O and its hybrids can reduce the pyrolysis product intensity and CO release.Raman analysis suggested that Cu₂O and its hybrids can facilitate the carbon transformation and increase the graphitization degree of the char,which is beneficial to suppress the smoke and toxic gases.2)Prepared a series of carbon-encapsulated microspheres Fe₂O₃?C,Cu@C and Cu₂O@Fe₂O₃@C by hydrothermal method,and introduced them into flame-retardant RPUF system.The Cone results demonstrated that the microspheres can obviously reduce the materials' HRR and SPR,in which Fe₂O₃@C was the most efficient.The Smoke Box test found that the three microspheres can all remedy the bad effect on smoke generation of APP/DMMP,but neither able to be comparable with the pure sample.In the FTTP section,the microspheres were not able to have an obvious influence on the smoke production at 650? neither well-ventilated nor worse-ventilated.For the CO release,however,the worse-ventilated was beneficial.The TG-IR results told that the microspheres reduced the pyrolysis product intensity,in which Cu@C performed the best.Raman analysis gave the conclusion that the microspheres also facilitate the carbon transformation and increase the graphitization degree of the char which can hinder the smoke and toxic gases efficiently.3)Prepared a series of hydrostannates ZHS,CHS and IHS with different morphologies by co-precipitation method,and applied them to flame-retardant RPUF system.The TG analysis found that the hydrostannates increased the RPUF's final char but made the decomposition earlier and the degradation temperature range narrower.The Cone test indicated that ZHS,CHS and IHS were not so helpful on the retardance of the HRR,but good enough to suppress the SPR.In the Smoke Box test,the hydrostannates were all efficient to reduce the smoke release.In the FTTP test,the hydrostannates couldn't help sueppress the smoke production,but could apparently reduce CO release.The TG-IR suggested that the hydrostannates followed the increasing order of ZHS,CHS and IHS in the suppression on the gas product intensity.Raman analysis also found that the IHS was the most efficient in increasing the graphitization degree of the char.4)Prepared two hyper-branched P,N-containing flame retardants CEPO and HBP,and applied them to the RPUF system.The Cone test indicated that 10 phr HBP was much better than 5APP/5HBP to reduce the RPUF's HRR,and the relavent SPR had almost closed to zero.In the Smoke Box test,the smoke production of RPUF/10HBP was obviously lower than that of RPUF/5APP/5HBP,and it would be more lower if Cu20,Fe₂O₃@C or ZHS added.In the test of FTTP,the smoke release of RPUF/10HBP had bear comparison with the pure RPUF,and the transmittance would come up to 100%if 5 phr ZHS added.In addition,the APP/CEPO and APP/HBP system were applied to PBT and PP matrix respectively,finding they were both quite efficient in the flame-retarding especially at the equal ratio.The TG-IR,SEM and Raman analysis proved the dual flame-retardant mechanisms of APP/CEPO both in gas phase and in condensed phase,while APP/HBP mainly in condensed phase.