Submitted to: Adhesion Society
Publication Type: Proceedings
Publication Acceptance Date: 2/18/2007
Publication Date: 2/18/2007
Citation: Biresaw, G., Felker, F.C. 2007. Morphological and rheological characterization of bioblends. Adhesion Society. p. 489-491.
Technical Abstract: Bioblends are polymer blends in which at least one of the components is a biodegradable polymer. Melt extruded model bioblends, comprising a biodegradable polyester and polystyrene (PS), were investigated using rheological and morphological (TEM) methods. Blend compositions were varied from neat PS to neat polyester, in 25% increments. The biodegradable polyesters were: polycaprolactone (PCL), polylactic acid (PLA), and poly(tetramethyleneadipate-co-terephthalate (EBU). Profiles of zero-shear viscosity (zsv) vs. % PS of the blends varied considerably, with EBU/PS showing a simple, monotonous transition between that of neat EBU and neat PS. At 75/25 composition, PCL/PS displayed a positive deviation of zsv, i.e., higher zsv than that expected based on the zsv of the components. On the other hand, at 75/25 composition, PLA/PS displayed a negative deviation of zsv, i.e., lower zsv than that expected based on the zsv of the components. Comparison of TEM images showed relatively large domain sizes in PLA/PS blends, and much smaller domain sizes in EBU/PS blends. The microstructure of the PS domains in PCL/PS blends suggests possible migration of a minor component or degradation product from PCL into the PS phase.