The Effect Of Inorganic Nano-hybrids On The Flame Retardancy And Smoke Suppression Properties Of Polymer

In recent years,with the rapid economic development in our country,people's awareness of environmental protection is getting higher and higher.At the same time,the green flame retardant has received more and more attention.Since inorganic flame retardants do not produce toxic and corrosive gases and are environmentally friendly,they have been the research hotspot in the field of flame retardancy.However,a single inorganic flame retardant is usually required in higher quantities and can affect other properties such as the physical and mechanical properties of the composite.Therefore,the use of two or more inorganic flame retardant components in combination can not only realize the vision of low added amount,but also improve the flame retardancy and smoke suppression performance of the composites.In this paper,MoS₂ was loaded onto the surface of titania nanotubes?TNTs?by hydrothermal method to prepare MoS₂-TNTs nanocomposites,and their effects on flame retardancy and smoke suppression properties of epoxy resin?EP?.MgAl-LDH was designed through the structural features of MgAl-LDH surface with strong positive charge.ZIF8 and ZIF67 were respectively loaded on the surface of MgAl-LDH by electrostatic interaction to obtain ZIF8@MgAl-LDH and ZIF67@MgAl-LDH hybrids.Then,they were respectively added to EP,and their effects of thermal stability,flame retardancy and smoke suppression properties on EP were investigated.CuMoO₄ was loaded on the surface of h-BN by coprecipitation to prepare CuMoO₄@h-BN and its application in PUE was studied.The effects of CuMoO₄@h-BN on the flame retardancy and smoke suppression performance of PUE were investigated.?1?A novel hybrid consisting of MoS₂ coating on TNTs surface?MoS₂-TNTs?was synthesized.The MoS₂,TNTs and MoS₂-TNTs hybrid was incorporated into EP to study the effect of its flame retardancy.The tests results showed that the char yield at 700 ?of EP/MoS₂-TNTs was increased obviously,compared with EP/MoS₂ or EP/TNTs,indicating that MoS₂-TNTs had a good carbonization effect.In addition,MoS₂-TNTs could improve the flame retardancy and smoke suppression of EP effectively.The reason was attributed to the physical barrier effect of MoS₂ and the adsorption of TNTs.?2?ZIF@MgAl-LDH hybrid was synthesized by zeolitic imidazolate frameworks?ZIF?and MgAl-layered double hydroxide?MgAl-LDH?via electrostatic interaction.Its structure and morphology were systematically characterized.Then,ZIF@MgAl-LDH was added to epoxy resin?EP?to improve its flame retardancy and smoke suppression properties.Compared with EP/MgAl-LDH,EP/ZIF@MgAl-LDH showed a lower peak heat release rate?PHRR?,total heat release?THR?and smoke density.ZIF@MgAl-LDH exhibited better flame retardancy and smoke suppression performance for EP.This was due mainly to:1),water molecules,N₂ and NH₃ generated from ZIF@MgAl-LDH during the combustion process that could dilute the concentration of O₂ and flammable gas;and 2),metal oxides produced by the decomposition of ZIF@MgAl-LDH that not only adsorbed smoke,but also promoted the formation of a char layer with a high degree of graphitization and high resistance to thermal oxidation.The char layer could suppress the diffusion of O2 and flammable gas,impede the transmission of heat radiation,and protect the underlying matrix from further combustion.?3?A novel flame retardant?CuMoO₄@h-BN?was synthesized,and its structure and morphology were systematically characterized.CuMoO₄@h-BN was added to polyurethane elastomers?PUE?to investigate the effect of thermal,flame retardancy and smoke suppression properties on the PUE composites.The results showed that 2 wt%CuMoO₄@h-BN increased the residual char yield of the PUE composite notably to 9.8%.CuMoO₄@h-BN exhibited an excellent charring effect.Compared with pure PUE,2 wt%CuMoO₄@h-BN decreased the PHRR,THR and smoke density of the PUE composite by 73.6%,52.4%and 28.2%,respectively.CuMoO₄@h-BN performed well in flame retardancy and smoke suppression.It may be attributed mainly to the physical barrier effect of h-BN and catalytic carbonization effect of CuMoO₄.