Study On The Preparation And Performance Of Halogen-free Environmentally Friendly New App Flame Retardant

With the widespread application of organic polymer materials,the use of flame retardants is also increasing,and it has leapt to the second place in plastic additives,second only to plasticizers.However,there are major problems in the consumption structure of flame retardant products.The proportion of halogen and halogen phosphorus flame retardants is too high,accounting for about 80% of the entire flame retardant market.Although halogen-containing flame retardants have good flame retardant effects and a wide range of applications,their serious disadvantage is that their flame-retardant polymer materials will produce a large amount of smoke and toxic gases when burned.In addition,halogen-based flame retardants are harmful to the environment and Human health is hazardous,potentially carcinogenic and teratogenic.Therefore,the global flame retardant market is undergoing product replacement,and the use of flame retardant products tends to be halogen-free and environmentally friendly.Ammonium polyphosphate(APP)will become an important growth point in the flame retardant market due to its good flame retardant effect,environmental protection,non-toxicity,and no secondary damage,and its research significance and economic value will also be highlighted.In view of the characteristics of APP according to different preparation conditions and different crystal forms,the preparation research and performance analysis of the crystalline type II and crystalline type V APP flame retardants are carried out.Each experimental step of the preparation process of APP was discussed in detail,the crystal form of the product was characterized by XRD diffraction pattern,and the influence of each step of the experimental conditions on the crystal form and performance of the preparation of APP was analyzed.After making qualified products,the two crystalline forms of APP are used for flame-retardant EPDM rubber,and the difference in the flame-retardant effects of different crystalline forms of APP is discussed.Wet ammonia gas is used to simulate the exhaust gas discharged from the APP production process,and the ammonia source is absorbed by phosphoric acid in an attempt to recycle the ammonia source,and the formed ammonium phosphate mixture is used as a raw material to prepare APP products again.Concluded as follow:(1)APP-? is the product of APP-? at high temperature.The optimum polymerization temperature for preparing APP-? using phosphorus pentoxide-diammonium hydrogen phosphate-melamine system is 290?.After the polymerization temperature is increased to 320?,APP-?is obtained.(2)The mechanism of the preparation of APP from the phosphorous pentoxide-diammonium hydrogen phosphate-melamine system is analyzed.Melamine is used as a condensing agent to participate in the formation of the long chain of APP.The APP produced by this system is not straightforward than ordinary APP.The chain structure is a net-like structure with branched chains.(3)APP-? and APP-? prepared under the best experimental conditions have no obvious difference in phosphorus pentoxide content,nitrogen content,solubility,p H value,thermal stability,etc.The two APP products have high substitution For APP products with degree of polymerization,the performance of the prepared APP products can meet the requirements of Class II products in "H/GT 2770-2008 Industrial Ammonium Polyphosphate".(4)The thermal weight loss curve of self-made APP-? and APP-? is basically the same.The self-made APP-?,self-made APP-?,and commercially available APP-? are compounded with DPER and MEL flame-retardant EPDM rubber for vertical combustion.Tests,self-made APP-? obtained the highest flame retardant grade of FV-0,self-made APP-? and commercially available APP-? both obtained FV-1 flame-retardant grade,APP-? can also be applied to high-performance flame retardant products.(5)Wet ammonia gas is used to simulate the exhaust gas discharged from the APP production process,and phosphoric acid is used to absorb and recycle the ammonia source in the exhaust gas.The formed ammonium phosphate salt mixture is used as the raw material to prepare APP products again.The performance of the prepared APP-? and APP-? products All of them can reach the first-class standard of Class I products in "H/GT 2770-2008 Industrial Ammonium Polyphosphate",saving resources and protecting the environment.