Nen-Sen Chen

Date of Award


Degree Name

Master of Science


Chemical and Paper Engineering

First Advisor

Dr. Raymond L. Janes

Second Advisor

Dr. James E. Kline

Third Advisor

Dr. John M. Fisher

Access Setting

Masters Thesis-Open Access


Fines and filler retention under dynamic conditions was studied in this thesis work. Zeta potential of samples are also measured. Dynamic Retention/Drainage Jar and Lazer-Zee Meter were used to accomplish this work. The results have been analyzed by statistical methods. When cationic starch was utilized as a retention aid the pH affected its efficiency, probably because the charge of cationic starch was dependent on pH. This effect was detected by utilizing two-way analysis of variance to find the sources of its interactions with molecular weight and agitation rate. The mechanism was thus determined. At pH 3 and 4, charge neutralization appeared to be the main mechanism for fines retention. And from pH 5 to 8, the mechanism became more dependent on polymer bridging. The charge neutralization mechanism did not appear involved in improving fines retention while the bridging mechanism did. The reason was concluded to be mainly due to the difference in charge between cationic starch and fiber fines.