Study On Microcellular FOAM Composites Of PP/Wood-Flour

Foaming wood-plastic composite is possessing of lower density and cost than the general wood-plastic composite, In this paper, the preparation and property of microcellular foam composites of PP/wood-flour was explored and studied.In this study, PP was selected as raw materials, benzoyl peroxide (BPO) as initiator, silane as monomer, styrene as assisted cross-linking agent, AC as blowing agent, sodium benzoate and talcum powder as nucleating agent using twin-screw extruder, two roll plastics mixing mill, compression molding machine etc. to the foamed board materials with homogeneous and fine cells by the compression molding with chemical crosslinking method before blowing.The various properties of modified PP were studied, the influence of the types and content of nucleating agent on the mechanical properties, apparent density, microcell size and distribution about PP foam materials was researched, to get a most suitable formula about and nucleating agent, the influence of the content of wood flour on the mechanical properties, apparent density, microcell size and distribution about the microcellular foam composites of PP/wood-flour was characterized, at last the influence of large amount addition of talcum on the mechanical properties, microcell size and distribution, apparent density about the microcellular foam composites of PP was investigated by capillary rheometer, SEM, density testing instrument, electronic tensioner and other machine testing mechanical properties.The results show that:(1) The melt strength of PP was enhanced by a method of silane cross-linking.(2) When AC was1.0phr and sodium benzoate was1.5phr, the foaming materials were prepared with the minimum cellular size and uniform distribution.(3) With the increase of wood flour content (from10to50phr), the tensile strength, bending strength and impact strength of foaming composite were raised first and then reduced slowly, while the apparent density was improved unobviously;(4) The microcellular foam composites of PP also could be prepared with large amount addition of talcum. The cellular size reached minimum and uniform when the content of talcum increasing from10to20phr.