Comparison On The Synthesis And Flame Retardancy Of Several Linear Macromolecular Triazine Charring Agents

Intumescent flame retardant(IFR)has become the main development direction of flame retardants because of its high efficiency,low smoke and low toxicity.Charring agent is a key component of IFR.The early used pentaerythritol has many defects due to its small molecular weight and large water solubility.In order to overcome these shortcomings,the research on new charring agent has been paid much attention.Macromolecular triazine charring agent is a new kind of charring agents with foaming,which has some merits of low toxicity,much less solubility in water and good compatibility with polymer,etc.At present,there are many triazine charring agents reported,among which the linear macromolecular triazine charring agent prepared using cyanuric chloride as a raw material is most valued due to its advantages such as cheap raw materials,simple synthetic process,low production cost and easy to adjust performance.However,the effects of side chain monomers and main chain monomers on the synthesis and properties of the linear charring agents have not been reported systematically.Therefore,the research on this was carried out in this paper.In this paper,13 macromolecular triazine charring agents were synthesized through condensation,polycondensation and butylamine termination using cyanuric chloride as a raw material,6 monoamines as side chain monomers,piperazine and ethylenediamine as main chain monomers,respectively.The results show that the side chain monomer and the main chain monomer exihibit a great impact on the synthesis of the above-mentioned charring agent.The stronger the hydrophilicity of the side chain monomer is,the greater the water solubility of the charring agent is,and the lower its synthetic yield is.The nucleophilicity of aromatic amine is weak,so the reaction activity with cyanuric chloride is lower,the substitution of chlorine is not very complete,which results in higher chlorine content and lower yield of carbon-forming agent;Compared with piperazine,ethylenediamine has strong hydrophilicity and weak nucleophilicity,so that the water solubility of ethylenediamine-based charring agents is larger,and its reaction activity with cyanuric chloride is lower,the substitution of chlorine is not very complete,which brings about the higher chlorine content and the lower yield of ethylenediamine-based charring agent.The termination with butylamine increases the yield and decreases the chlorine content of products,but the effect was not obvious.The results of thermogravimetric analysis show that the side chain monomer and the main chain monomer have significant effects on the thermal stability of the carbonizing agent.The thermal stability of the charring agent using ethanol amine as a side chain monomer is best,followed respectively using aniline and morpholine,then using butyl amine,and using diethanolamine is poorer,while using ammonia is worst;The thermal stability of the piperazine-based charring agents was better than that of the ethylenediamine-based charring agents.The termination with butylamine has little impact on the thermal stability of triazine charring agents.The results of LOI measurement,UL-94 test show that the side chain monomer and the main chain monomer exihibit a great impact on the flame retardancy,smoke and CO suppression of the carbonizing agent.The more hydroxyl the side chain monomer contains,the better the flame retardancy,smoke and CO suppression of the corresponding charring agent are.The charring agent with side chain monomers without hydroxyl has poorer flame retardancy,smoke and CO inhibition.The charring agent with ammonia as a side chain monomer is the worst in the above-mentioned performances.The above-mentioned performances of piperazine-based charring agents are better than that of ethylenediamine-based charring agents.The termination with butylamine can improve the performances of charring agents,but the effect is less.The addition of the flame retardants reduces the thermal stability of PP,and the side chain monomers have a great impact on the thermal stability of FR-PP.For piperazine-based charring agents,ethanolamine and ammonia have greater effect on the thermal stability of FR-PP than that of the other side chain monomers;However,for ethylenediamine-based charring agents,the effect of ethanolamine on the thermal stability of FR-PP was smaller than that of butylamine.The main chain monomer and the termination have little effect on the thermal stability of FR-PP.The flame retardancy of the charring agents is related to the impact of various factors on the residual,expansion degree,quality and structure of the charring layer.Higher residual,better expansibility and quality as well as denser structure of the charring layer result in better flame retardancy.Comprehensive considering the above-mentioned results,the balanced performances of the charring agents prepared using ethanolamine as a side chain monomers are good,and the synthetic cost is lowest,the performance of the piperazine-based charring agent is better than that of the ethylenediamine-based charring agent,and the emission of waste water and gas is also lower,but the synthetic cost of the latter are lower than that of the former.