Organic modification of precipitated calcium carbonate nanoparticles as filler in LLDPE/CNR blends with the presence of coupling agents: impact strength, thermal, and morphology

This study reports that Precipitated Calcium Carbonate (PCC) nanoparticles from limestone can be modified with oleic acid (OA), which was applied to LLDPE/CNR blends in the presence of the LLDPE-g-OA coupling agent. This study investigates PCC characteristics from limestone that has been modified with OA and its implications of increasing impact strength, thermal properties, and morphology changes in LLDPE/LLDPE-g-OA/CNR/O-PCC composites. Organo-PCC (O-PCC) was prepared by mixing the PCC with OA in n-hexane solvent. The polymer composites were made by mixing LLDPE, LLDPE-g-OA, and CNR simultaneously in an internal mixer at 160 °C with speed rotation of 100 rpm, followed by O-PCC. The characterization results of O-PCC obtained CaO compounds of 97.9%, crystallinity degree of 61.6%, crystals size of 48.6 nm, and scalenohedral-shaped crystals. The results of the impact strength test on LLDPE/LLDPE-g-OA/CNR/O-PCC composites with an O-PCC concentration of 5 wt% showed an increase of 21.5% compared to no fillers. The presence of O-PCC resulted in the thermal properties of polymer composites with a melting point of 125.5 °C and a decomposition temperature of 468.7 °C. The morphology did not result in significant differences in the surface structure after adding O-PCC nanoparticles.