Date of Award

12-1994

Degree Name

Master of Science

Department

Chemical and Paper Engineering

Department

Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. James E. Kline

Second Advisor

Dr. David K. Peterson

Access Setting

Masters Thesis-Open Access

Abstract

Four different classes of commercial rheology modifiers (thickeners) e.g., Polyacrylate (PA), Associative Cellulosic Thickener (ACT), Associative Synthetic Thickener (AST) and CMC were used in a simplified coating formulation to study their effects on rheological and viscoelastic properties of the coating colors. An attempt was also made to study their effect on runnability using the Cylindrical Laboratory Coater (CLC). A series of coatings were prepared using number one clay and styrene-butadiene latex. The thickeners were added to these at several levels. The coatings were evaluated for rheological and viscoelastic properties. The coatings were also applied onto paper using the CLC at several blade run-in values (blade pressures) to assess the runnability. The results show that AST has the highest power of viscosifying the coatings at a given level of addition. AST was also found to have the highest low shear (Brookfield) and lowest high shear (Hercules) viscosity. Among those studied, AST contributed to lower blade run-in values to get a required coat weight. Coatings with AST relaxed faster during stress relaxation tests than those with other thickeners. Although nothing could be said conclusively about runnability, AST contributed to relatively trouble-free runs on the CLC.

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