Studies On Anti-hygroscopicity Modification Of Ammonium Nitrate Coated By Using Poly-(Meth) Acrylates

In this paper,in order to improve the anti-hygroscopicity,the coating methods of crosslinking polymerization,copolymerization and surface adsorption were used to modify the industrial ammonium nitrate(AN)particles,by using(meth)acrylates and surfactants as monomers.Firstly,based on the existing literature,using the glass transition temperature of polymers,molecular weight and their distribution of both crosslinking and copolymers as the criterions,the potential sorts within the polymers to be used as coating materials were selected.Secondly,using the decline of hygroscopic rate and the mass fraction of coating layer as the indexes,the optimum coating process conditions were obtained by single factor exploration experiments and orthogonal optimization experiments,and the influences of various factors of coating process on the decline of hygroscopic rate and the mass fraction of coating layer were studied respectively.Finally,the coated sample and its coating layer were characterized and analyzed by SEM and FTIR,respectively.The results were shown as follows:(1)The optimum coating AN conditions by using single factor exploration and orthogonal optimization experiments were that n(Methyl methacrylate):n(Butyl acrylate)=1:1,the volume of solvent A was 30mL,the monomer mass rates were 20%(w/w)to solution,AIBN was 0.7%(w/w)to monomers,the coating reaction was conducted under stirring,the reaction temperature was 60? and the reaction time was 8h.Then the reaction was stopped,cooled under reflux to 30°C,and the coated samples were filtered and dried.The hygroscopic testing conditions were that the relative humidity was 68%,testing temperature was 35 ?,?and testing time was 24h.Under these conditions,the decline of hygroscopic rate of 5g coated sample was 30.7%with the mass fraction of the coating layer 1.4%to the AN particles.(2)It was showed from the characteristics of SEM that the surface of the coated samples became compact and smooth,and the holes and cracks on the surface were reduced.It was showed also from the characteristics of FTIR that the copolymers had been coated on the surface of AN.In this paper,the efficiently anti-hygroscopic coated particles of AN and the optimum conditions were obtained.These work mentioned above could provide a good basis for improving the effect of the anti-hygroscopicity of ammonium nitrate particles.