Investigations on the preparation of starch/sodium oleate/alum modified precipitated calcium carbonate filler and its use in papermaking

摘要

In order to improve the strength properties of calcium carbonate filled papers, starch, sodium oleate and alum were used in the encapsulation modification of papermaking grade precipitated calcium carbonate (PCC) filler, and the effect of filler modification on encapsulated amount, furnish drainage and paper properties were analysed and evaluated. The results showed that, starch, sodium oleate and alum were effective in filler modification, and alum was an efficient precipitation agent in the encapsulation modification process at certain conditions. Filler modification only had negligible effect on static furnish drainage, however, the tensile strength and burst strength of filled handsheets were significantly improved, and filler retention was also improved at certain conditions. Additionally, after modification, the brightness of filled handsheets was negatively influenced to a minor degree, however, the opacity and light scattering coefficient increased slightly at certain alum dosages. SEM, XRD and XPS results confirmed the occurring of surface encapsulation and modification of PCC filler when the relevant modifiers were used.