Characterization of melt-compounded and masterbatch-diluted polypropylene composites filled with several fillers

The effect of various fillers on the mechanical, barrier, and flammability properties of polypropylene (PP) was studied. PP was filled with 4 wt% of nano-sized calcium carbonate, titanium dioxide, organoclay, and multiwalled carbon nanotube (MWCNT). For comparison, micron-sized calcium carbonate was also studied. Two-step masterbatch dilution approach of the composites suggested no or only minor improvements in Young's modulus and tensile yield strength, whereas their ductility decreased compared to coupling agent-modified PP matrix. The water vapor transmission results of filled films showed increased permeability compared to their coupling agent-modified counterpart. Oxygen permeability, however, decreased for the composites. The MWCNT-filled matrix showed the highest barrier and fire performance, attributed mainly to its higher filler volume content, but also other reasons such as the effect of filler dispersion, composite's thermal stability, and polymer crystallinity were discussed.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers