Preparation Of Polyacrylic Core-shell Particles And Toughness On Nylon 6

Engineering plastics is a kind of high performance plastics that may replace metal materials. Compared with metal materials, engineering plastics with excellent electrical insulation, thermal insulation, and chemical resistance is easy to process and compound with glass fiber and fillers. With the development of science and technology, pure engineering plastics cannot meet the industrial requirements, and more and more people begin to study how to modify it in order to obtain excellent comprehensive properties. Nylon 6(PA6) has high mechanical strengths, thermal deformation temperature, excellent fire resistance and wear resistance, self-lubrication and so on. As the low notched impact strength of PA6 limits its extensive application, it is necessary to toughen it.In this study, the polyacrylic core-shell particles [PBA/P(MMA-co-MAA) and PBA/P(MMA-co-AA)] were prepared by seeded emulsion polymerization using thermal initiator system, in which poly(butyl acrylate)(PBA) was used as the core layer, poly(methyl methacrylate)(MMA) as the shell layer, and methylacrylic acid(MAA) or acrylic acid(AA) as a functional monomer in the shell. The monomer’s conversion was determined by gravitation and the particles size by laser dynamic light scattering(DLS).Transmission electron microscopy(TEM) was used to observe the particle diameters and the morphology. PA6/polyacrylic core-shell particles blends were prepared through a twin-screw extruder by melting extrusion. The mechanical properties of the blends were investigated. Scanning electron microscope(SEM) was used to observe the fractured surfaces, and dynamic mechanical analysis(DMA) to study the compatibility between PA6 and polyacrylic core-shell particles.The suitable compositions were determined by orthogonal experiment that crosslinking agent(ALMA) content and PBA content were two most important factors to affect the toughness of PA6. We mainly studied the effect of different ALMA contents and PBA contents on the toughenness of PA6. Finally, blends with two kinds of functional monomer were used to toughen PA6. It was found that the polymerization had a very high conversion and the particles had an obvious core-shell structure. The notched impact strength of PA6/polyacrylic core-shell particle blend with MAA as functional monomer, 0.5% ALMA content and 85% PBA content were almost 6 times greater than pure PA6, and the mechanical properties agreed well with the SEM observation.