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Title: SURFACE ENERGY PARAMETERS OF POLYMERS FROM DIRECTLY MEASURED INTERFACIAL TENSION WITH PROBE POLYMERS

Author
item Biresaw, Girma
item Carriere, Craig

Submitted to: Journal of Adhesion Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2004
Publication Date: 12/1/2004
Citation: Biresaw, G., Carriere, C.J. 2004. Surface energy parameters of polymers from directly measured interfacial tension with probe polymers. Journal of Adhesion Science and Technology. 18(14):1675-1686.

Interpretive Summary: Prices of farm products and incomes of farmers are highly dependent on the demand for farm products relative to supply. Over the years, prices have been depressed due to oversupply. One way of increasing the demand is by developing new applications for farm products, or by using farm products to replace other products (e.g., petroleum products) in existing applications. Agricultural products have the potential to partially or fully replace synthetic products in a number of material applications. However, converting this potential to reality will require a thorough understanding of the mechanisms that control the compatibility of blends. One of the factors affecting blend compatibility is interfacial tension. In this work, an improved method for predicting the surface energy parameters of blend components is described. Surface energy parameters can be used to assess the compatibility of blend components, thereby speeding up the development cycle of new ag-based products.

Technical Abstract: The surface energy parameters of polycaprolactone (PCL) and polyethylene (PE) were determined at 160 and 180ºC from their interfacial tensions with probe polymers. The probe polymers were PS and PMMA. This method is based on the well-known relationship between blend interfacial tension and polymer surface energy parameters, and requires the use of at least two probe polymers, whose surface energy parameters at the temperature of interest has been independently determined. It also requires direct measurement of blend interfacial tension at the high temperatures of interest. The interfacial tensions were obtained from direct measurements by the imbedded fiber retraction method. The following results were obtained: (a) gP values for PCL and PE were within the range reported using other methods, (b) gP values increased in the order PE << PCL, which is consistent with the chemistries of the two polymers, (c) gD values for PCL and PE decreased with increasing temperature, consistent with expectations, (d) gD values for PCL were on the high end, but still within the rather broad range of reported values, and (e) gD values for PE were much higher than expected.