PREPARATION AND CHARACTERIZATION OF POLYPROPYLENE/ATTAPULGITE NANOCOMPOSITES

Abstract

(Polypropylene(PP)/attapulgite(ATP)) nanocomposites with enhanced mechanical properties were prepared by a simple and efficient method of melt blending without adding any bulking agent.ATP was pretreated by emulsion oxidized polyethylene envelop,and then dispersed by strong shear stress.The novel pretreatment method in preparing nanocomposites leads higher mechanical properties than those of PP/untreated ATP nanocomposites and pure PP.The impact strength of the composites was increased by 44%～83%,and the tensile strength was increased by 6%～11%.At the mean time,the flexural strength was increased by 33%～45% and the modulus of flexural was increased by 90%～106%.Scan electron microscope(SEM) results reveal that ATP disperses homogeneously in the PP matrix and mainly exist in the form of anomocytic crystal bundle.The diameter of treated ATP units is in the range of 20～40 nm that is much less than that of untreated ATP which is in the rang of 50～80 nm.X-ray diffraction(XRD) shows that PP exhibits α crystals in the composites,and no crystalline phase transition occurrs as reported in literature.The size of PP crystallites was decreased with the addition of ATP.Dynamic mechanical analysis and the results of differential scanning calorimetry(DSC) reflected that the addition of ATP can increase the crystallization temperature and crystallinity of PP/ATP.It is proved that the addition of ATP also gives nucleation effect.The enhancement of the mechanical properties is mainly contributed by the uniform dispersion of ATP and strong interfacial force of PP/ATP.