Enhancement of properties of PA6/PP nanocomposites via organic modification and compatibilization

Abstract

Nanocomposites based on polyamide 6/polypropylene (PA6/PP = 70/30) blend containing organophilic mont- morillonite (OMMT) and maleated polypropylene (PP-g-MA) as compatibilizer were prepared by melt compounding fol- lowed by injection molding. Modification of montmorillonite (MMT) with dodecyalmine was successfully performed. The morphological and mechanical properties of nanocomposites were investigated by using x-ray diffraction (XRD), transmis- sion electron microscopy (TEM), tensile, flexural, and impact tests. The thermal stability of nanocomposites was character- ized by using thermogravimetric analysis (TGA) and heat distortion temperature (HDT). XRD and TEM results indicated that the intercalated structure was obtained for PA6/PP/MMT composite, a mixture of intercalated and exfoliated structures for PA6/PP/OMMT nanocomposite, and exfoliated structure for PP-g-MA compatibilized PA6/PP/OMMT nancomposite. Thermal stability and HDT of PA6/PP matrix were improved by the addition of both MMT and OMMT. The introduction of PP-g-MA into the PA6/PP/OMMT nanocomposite enhanced the properties such as stiffness, strength, ductility, impact strength, and HDT. This was attributed to the compatibilizing effect of PP-g-MA which improved interfacial adhesion between OMMT with PA6/PP matrix and also promoted the degree of exfoliation of silicate layers in the PA6/PP matrix.