The Effect of Cationic Modification of Precipitated Calcium Carbonate (PCC) on the Optical and Physical Properties of Paper

In this study, precipitated calcium carbonate (PCC) was modified using cationic starch, and its effect on optical and physical properties of paper was examined in comparison with unmodified filler afterwards. To determine the filler retention in paper, both modified and unmodified fillers were added to pulp suspensions by 20, 30, and 40 percentages. For comparing the utilization effect of modified and unmodified PCCs, filler content as assigned by preliminary tests that final papers contained 10, 16, and 30 percentages of filler, based on dry weight pulp. Results indicated that papers containing modified-filler have more values of retention rather than those with unmodified filler, both in 20% and 30% filler dosages. Among the two mentioned dosages, highest value of retention and ash belongs to PCC-15% S that its modification also consumed most amount of starch was. Obviously, adding the dosage rate of fillers (both modified and unmodified) increased the brightness of papers. It found that papers filled with modified-filler have lower opacity than those are unmodified. It obtained from X-ray spectrums that both modified and unmodified fillers are composed from calcite, while the units are different in terms of geometry.