Interfacial interactions in calcium carbonate-polypropylene composites. 1: Surface characterization and treatment of calcium carbonate: A comparative study

Calcium carbonate (CaCO3) was modified with two types of coupling agents based on fatty acid and titanate. The efficiency of the surface treatment was studied through a dissolution method. The change in surface properties was characterized by inverse gas chromatography at both infinite dilution and finite concentration. It was found that a small amount of coupling agents caused, a drastic decrease in surface energy, which varied as a function of bonded coupling agents. The completely covered CaCO3 exhibited a surface of little polarity. Infrared analysis showed that stearic acid reacted extensively with the filler surface to produce chemically bound organic salt compound, in addition to the increase in peak intensity due to the methylene vibration of the alkyl chain. However, instead of directly observing the transesterification reaction between LICA 12 and the filler, only an increase in the peak intensity due to absorption of the phosphate stretching was detected.