Effect of Interfacial Modification on the Rheological Properties and Nucleation Behaviour of PP-BaSO_4 Composites

摘要

Polypropylene-barium sulfate (PP-BaSO_4) composites were prepared by pretreating the filler with stearic acid,silane and polypropylene-g-maleic anhydride,respectively.The effects of the PP-BaSO_4 interfacial interaction on the rheological properties and nucleation behaviour of the composites were studied.Surface treatment with reactive coupling agents enhanced the matrix-filler interfacial interaction and caused an increase in the melt viscosity,whereas the use of non-reactive coupling agents reduced the particle-particle interaction and led to a decrease in melt viscosity.The plain BaSO_4 had a weak nucleating effect on PP.When the PP-BaSO_4 interaction was enhanced,a remarkable increase in nucleation activity of the filler was observed.It is suggested that the enhanced adsorption of PP molecules onto the BaSO_4 surface is of benefit in lowering the thermodynamic potential barrier for the formation of primary nuclei.