Preparation Of Polyacrylic Core-shell Particles And Toughness On PA6/PBT Blends

The application of engineering plastic alloy has become more widespread used in automobiles,electronics,chemical industries and other fields due to their easy processing,low cost,less pollution and high performance.PA6/PBT is one of such engineering plastic alloy.Blending PA6 with PBT was supposed to be a feasible way to improve the high water absorbability of PA6 and low notched impact strength of PBT and prepared a polymer material with high comprehensive performance.However,PA6/PBT blends have rarely been used owing to the poor compatibility between PA6 and PBT components,which would decrease the notched impact strength of blends,even inferior to those of pure PA6 or PBT component.Therefore,it is imperative to toughen PA6/PBT blends.The polyacrylic core-shell particles as a toughening modifier and a compatilizer were employed to toughen PA6/PBT blends in this study.On the one hand,the functional monomer in shell layer could improve the compatibility between PA6 and PBT by chemically reacting with both PA6 and PBT;on the other hand,the rubber core was used to increase the notched impact strength of PA6/PBT blends.In this paper,poly(n-butyl acrylate)/poly(methyl methacrylate),a core-shell structured modifier,was prepared by seed emulsion polymerization.The functional monomer was grafted onto shell layer to improve the compatibility of PA6 and PBT.The morphology of the final latex particles was examined by transmission electron microscope(TEM).The particle size was measured online with dynamic light scattering(DLS)and the monomers'conversion was determined by gravimetric method.Then the core-shell modifier was blending with PA6/PBT(80/20)blends in a co-rotating twin-screw extruder and the pelletized materials were injection molded into standard specimens using an injection machine.The toughening effect of species and amount of functional monomers at the shell and the amount of core-shell particles on the PA6/PBT blends was studied in this paper.The mechanical properties of the blends were investigated by using a universal tensile tester and an impact testing machine.The water absorption,the compatibility between PA6/PBT blends and core-shell particles,the morphology of notched impact-fractured surfaces of blends and the effect of core-shell particles on the thermostability of blends were studied with water absorption tests,dynamic mechanical analysis(DMA),scanning electron microscopy(SEM)and thermo-gravimetric analysis(TGA),respectively.Based on the above studies,we found that the notched impact strength of blends was 25.66 KJ/m~2,which was 3.04 times higher than that of pure PA6/PBT when MAA as the functional monomer,and the amount of MAA was 0.75%and the content of core-shell particles was 23.0 wt.%loading.Meanwhile,the water absorption of blends was only 1.3%,decreasing by 53.6%compared with PA6 and 26.6%with PA6/PBT.SEM observation of the fractured surfaces of the blends showed that core-shell particles were homogeneously dispersed in the PA6/PBT matrix.TGA analyses and DMA results also revealed the optimal compatibility was achieved when the content of core-shell particles was 23.0 wt.%.It could be concluded that the method of employing core-shell structured particles was an effective approach to achieving PA6/PBT blends with high-toughness and low water-absorption.