Ammonium Polyphosphate(APP)Microencapsulation And Its Application

Ammonium polyphosphate(APP)is a new type of non-halogen intumescent flame retardant with excellent performance.It has been widely used in recent years due to its good chemical stability,low hygroscopicity,excellent dispersibility,small specific gravity and low toxicity.It is used for fire protection in all aspects;However,because of its structural defect,APP has some problems such as low initial decomposition temperature,poor water resistance,poor compatibility with polymer,etc.,especially poor compatibility with polymerization.After a long time of standing,the flame retardant will migrate from the polymer system and precipitate to the surface of the polymer,and a"Frosting" phenomenon will appear.Therefore,it is necessary to modify for the APP.At present,the modification of APP mainly about surface organization and microencapsulation.In order to solve these problems,this paper designed and prepared microencapsulated ammonium polyphosphate with multi-layer structure,and the internal inorganic nanoparticle water blocking layer has good water resistance;the outer layer of triallyl-cyanurate can not only participate in flame retardation but also has good compatibility,and can also participate in flame retardant at the time of char formation,the flame retardant performance is improved.main tasks as follows:1.The microcapsule structure with ammonium polyphosphate as the core and inorganic nanoparticles as the shell was designed to realize the self-assembly of the water-blocking layer and improve the water resistance of ammonium polyphosphate.After microencapsulation,it was found that the water-resistance of the micro-encapsulated ammonium phosphate in the inorganic nanoparticles was greatly improved in the water,close to neutral,and gradually became weaker with time;The water contact angle test found that after microencapsulation of the inorganic capsule,the contact angle was increased from 7.8° to 21°,and the hydrophobic properties were also improved to some extent.In summary,the hydrolysis performance of ammonium polyphosphate after microencapsulation of the inorganic capsule material is improved.2.A kind of ammonium polyphosphate with micro-encapsulation of inorganic nanoparticles was used as the core,and the inorganic nanoparticle microcapsules were sealed by external hydrolysis and condensation with silane coupling agent to improve the water resistance of ammonium polyphosphate.The graft modification of the silane coupling agent can also improve the compatibility of the ammonium polyphosphate with the polymer.The contact angle test found that the contact angles of ammonium polyphosphate modified by KH-550,KH-560,KH-580 and A-151 were:64°,89°,93°,98°,respectively.The contact angle of ammonium polyphosphate using microcapsules of inorganic capsules is greatly increased;In addition,ammonium polyphosphate grafted with different silane coupling agents are applied to different polymers,and it is found that:KH-550 and KH-560 graft modified ammonium polyphosphate was applied to epoxy resin E-51,the results showed that the mechanical properties of the flame retardant epoxy resin with added ammonium polyphosphate after microencapsulation were higher than those of the original ammonium polyphosphate.The oxygen resin has a certain improvement,which is increased from 33.84 MPa to 42.95 MPa and 43.03 MPa,respectively.3.A microencapsulated ammonium polyphosphate modified by silane coupling agent was designed as the core,and the outer layer was triallyl cyanurate.The microencapsulated ammonium polyphosphate was used in flame retardant natural rubber.When a chemical bond is formed between the ammonium polyphosphate and the polymer,the compatibility of the ammonium polyphosphate with the polymer is effectively improved;and the triallylcyanurate is used as a triazine carbon-forming agent,so that ammonium polyphosphate becomes a highly efficient intumescent flame retardant with both acid source,origin and carbon source.The prepared microcapsule ammonium polyphosphate of the microencapsulated structure was applied in natural rubber,and after vulcanization in a flat vulcanizer using sulfur as a vulcanizing agent,the results showed that the ammonium polyphosphate after microencapsulation was resistant to water.The properties and compatibility are significantly improved compared with the original ammonium polyphosphate.The mechanical properties,flame retardancy and water-resistant migration of the flame retardant natural rubber of the ammonium polyphosphate.After microencapsulation ammonium polyphosphate are added into natural rubber,the flame retardant with great improved compared with the original ammonium polyphosphate.There is a certain increase in rubber.