mechanical properties, shrinkage behavior and water absorption of pa6/pp/caco3 nanocomposites

nanocomposites based on polyamide 6/polypropylene  )pa6/pp 67/33) blend containing 2.5 to 10 phr of nano-caco3  and 5 phr of maleated polypropylene )pp-g-mah) as compatibilizer were prepared by melt compounding followed by injection molding. the mechanical properties, water absorption, as well as shrinkage behavior were characterized and the morphology was studied using scanning electron microscopy. the presence of pp, pp-g-mah and nano-caco3 lowered the amount of water absorption as high as 72 wt%. morphology analysis indicated that the addition of pp-g-mah can signifcantly  improve  the adhesion between pa6 and pp phases. the incorporation of pp-g-mah led to 24% increase in fexural and impact strength, 27% rise in tensile strength and approximately 100% increase in elongation-at-break. the addition of nano-caco3 particles  increased  the  impact  resistance  and fexural strength. the  results  of  experiments  indicated  that  the maximum  fexural  strength was achieved by adding 5 phr of nano-caco3 which was 16% greater than pure pa6, and the maximum impact strength was attained by adding 7.5 phr of nano-caco3 which was 29% superior compared to pure pa6. the incorporation of 10 phr of nano-caco3  particles  led  to fller  agglomeration  and,  consequently,  the  impact  strength was dramatically dropped. dimensional characterization of molded samples revealed that the incorporation of pp-g-mah can raise the shrinkage, but the addition of nano-caco3 has not had any considerable effect on the shrinkage of nanocomposites.