Rongjuan Cong

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Chemical Engineering


Professor Robert H. Pelton


High molecular weight poly(ethylene oxide) (PEO) is an effective flocculant in the papermaking process. The performance of PEO can be greatly enhanced in the presence of second polymeric component. This second component is called cofactor in paper technology literature. In this thesis, poly(vinyl phenol-co-styrene sulfonate (PKS) is chosen as a model cofactor. The mechanism for complex formation between PEO and PKS, the transport properties of PEO/PKS complexes, the relationship between PEO/PKS complex formation and flocculation are discussed. PEO mainly interacts with aromatic groups of PKS through hydrogen bonding and hydrophobic interactions. The widely proposed hydrogen bonding mechanism between phenolic hydroxyl group and ether oxygen is investigated by comparing the complex formation, flocculation performance between PEO/PKS and PEO/poly(styrene-co-styrene sulfonate). Phenolic content, salt, temperature and PEO molecular weight affect the complex formation and flocculation efficiency. A hydrophilic, sterically stabilized and negatively charged colloidal model, dextran sulfate modified precipitated calcium carbonate, is developed to mimic the solution properties of fillers in papermaking flocculation. This work gives a better understanding about PEO/cofactor flocculation mechanism.

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