Date of Award


Degree Name

Bachelor of Science


Paper Science and Engineering


This paper was designed to develop insights on the retaining, optical efficiency and filler distribution properties of retention aids at various pH levels. Three leading retention aids; Cato 15, Natron 86 and Nalco 623 were studied in the normal papermaking pH range 3.5 to 6.5 to determine the effect of pH.

The results indicated pH played an important role in producing conditions of optimum retention and optical efficiency. pH also contributed to the distribution of the filler in the handsheets. The results further indicated, when using retention aids, optimum retention of titanium dioxide does not always yield the highest scattering coefficients. Furthermore, it was found higher scattering coefficients resulted in handsheets without retention aids than in handsheets using retention aids, if the sheets contained the sane amount of titanium dioxide.

The pH levels at the time of sheet formation where maximum retention existed for Cato 15, Natron 86 and Nalco 623 were 5.5, 4.5, and 6.0. While the pH levels for optimum scattering coefficients for Cato 15, Natron 86 and Nalco 623 were 6.5, 6.5 and 4.0 respectively.