Comparative analysis of the mechanical, thermal and barrier properties of polypropylene incorporated with CaCO3 and nano CaCO3

The primary advantages of polyolefins are that their properties can be improved through the use of additives. Polypropylene (PP) is a semi-crystalline polyolefin that has several advantages such as high strength, and low cost. However, it exerts some disadvantages, including a high molding shrinkage factor, poor mechanical properties, and low fracture toughness, which limit the widening of PP applications. This study investigates the influence of two types of fillers micro CaCO3 and nano-CaCO3 on PP composite mechanical, thermal, morphological and barrier properties and applications. The selected fillers were mixed at a different wt% with PP and compounded in a twin-screw extruder under 150 RPM and 180-200 degrees C, and all specimens were rested for 24 h to dry before cutting and testing. All experimental results were analyzed by statistical arithmetic mean, the specimen micrographs revealed a good distribution of both fillers with a more visual pore throat shape in the PP/ CaCO3 composite structure. Where DMA test demonstrated that PP with CaCO3 had reached the full rubbery zone earlier than PP with nano-CaCO3 by 30oC, reflecting that the incorporation of the nanofiller has revealed better thermomechanical property. Moreover, the nanofiller has increased the crystallization temperature for the composite by 14%, and the calculated permeability for all PP mixed with nano-CaCO3 was reduced and averaged just above 7.0 g/m2x 24 h. Overall, the selected PP grade with low nanofiller content has demonstrated better enhancement to the PP nanocomposite general properties.