Surface modification of precipitated and ground calcium carbonate fillers

In this study, the surfaces of precipitated calcium carbonate (PCC) and ground calcium carbonate (GCC) fillers were modified using different ratios of starch/fatty acid, starch/rosin, microfibrillated cellulose (MFC)/polyamine, and carboxymethyl cellulose (CMC)/polyamine mixtures. Tests were conducted to evaluate the effects of the modified filler materials (MDM) on particle charge densities, electrical zeta potential values, particle size distributions, FTIR, SEM images, starch adsorption, and paper properties. The results indicated that increasing the cationic charge amount enhanced the filler adhesion. Also within the study, starch mixture consumption of calcite increases with the amount of calcite and fatty acid or rosin that enters the mixture. However, it was observed that this phenomenon improved the paper's tensile strength rather than the adhesion of the filler material. It has been determined that starched modifications increase the tensile strength of the paper by approximately 70% compared to the control paper according to MFS and KMS applications, while it provides approximately 40% more filler retention than starched modifications. Fillers modified with MFC/polyamine exhibited greater adhesion to fibers and improved strength properties of the paper compared to starch/fatty acid and starch/rosin mixtures. Analysis of the size distribution of the modified filler materials post-modification revealed that macro-agglomeration did not occur during the process, indicating suitability for use. Statistical evaluations of the average adhesion values of MFM and the paper's tensile strength indicated that the groups were homogeneously distributed according to the Levene test, while significant differences between the groups were observed based on the Benfori and SNK tests.