A Green Process For Preparation Of Microencapsulated Red Phosphorus And Its Application

A green environmental technology was developed to prepare microencapsulated red phosphorus(RP) with a coating of melamine formaldehyde resin(melamine) serving as flame retardant. In this thesis, microencapsulated red phosphorus(MRP) was prepared through inverse suspension polymerization of melamine and formaldehyde(MF) on the surface of red phosphorus(RP) powder. The composites of plastic and MRP were prepared by directly reactive extrusion of polypropylene(PP), or low density polyethylene(LDPE), or polyamide 6(PA6) with MRP powder. The flame retardant and properties of PP/MRP, LDPE/MRP and PA6/MRP composites were also studied.From the FT-IR and SEM spectra analysis it was shown that the products were obtained to confirm that melamine formaldehyde resin existed. From the TGA spectra analysis it was shown that the MRP at 385℃-422℃ and 470℃-553 ℃ has two weight loss. From the XPS spectra analysis it was shown that the surface of MRP was not detected out of phosphorus(P) signal. Preparation of flame retardant can accord with the characteristics and requirements of MRP by inverse suspension polymerization.Research shows that MRP by inverse suspension polymerization preparation is the best experimental conditions: Inverse suspension polymerization of oil phase and water phase reaction volume ratio was 3:1 and using Span80 as dispersant, the amount of 1%, Melamine and Formaldehyde was 1:3, pH=5-6, reaction temperature 60 C, the stirring speed is 200r/min under the experimental conditions, the prepared MRP coating rate and optimal performance.MRP was applied in the preparation of PP/MRP, LDPE/MRP and PA6/MRP composites, by melt blending. The mechanical properties and flame retardant properties were evaluated. The study of the PP/MRP composites showed that when the dosage of MRP was 10 phr, the limiting oxygen index of the composites(LOI) reached 22.4%. The increment of LOI, flexural strength, flexural modulus of the PP/MRP composites is 5% and 1%, Compared with the composite without MRP addition. But tensile strength, elongation at break, notched impact strength decreased. The study of the LDPE/MRP composites showed that when the dosage of MRP was 10 phr, the limiting oxygen index of the composites(LOI) reached 23.6%. The increment of LOI, flexural strength, flexural modulus of the PP/MRP composites is 6.2% and 1.4%, Compared with the composite without MRP addition. but tensile strength, elongation at break, notched impact strength decreased with the increase of MRP content. The study of the PA6/MRP composites showed that when the dosage of MRP was 10 phr, the limiting oxygen index of the composites(LOI) reached 27.2%. The increment of LOI, flexural strength, flexural modulus of the PP/MRP composites is 4.7% and 1.06%, Compared with the composite without MRP addition. But tensile strength, elongation at break, notched impact strength decreased with the increase of MRP content. But with the increase of MRP content, the tensile strength and tensile modulus of the composites decreases first and then increases, the elongation at break decreased.The results of the study show that: the preparation of melamine formaldehyde resin microcapsule red phosphorus is a kind of new green industrial production process of inverse suspension polymerization. The prepared coating rate is high, the excellent performance of Microencapsulated Red Phosphorus Flame retardant. And applied to a variety of polymer materials, can play a good flame retardant effect.