Phase Equilibria and Transition in Mixtures of a Homopolymer and a Block Copolymer. II.
Abstract
The phase relationship in mixtures containing a block copolymer and a homopolymer has been studied by means of light scattering. The copolymer employed is a styrene-butadiene block copolymer of molecular weight (Mw) 28000, containing 27% styrene. The homopolymer in the mixture is either (1) polystyrene of Mw 2400, (2) polystyrene of Mw 3500, or (3) polybutadiene of Mw 26000. The first system containing the lower molecular weight polystyrene was previously studied in detail also by means of small-angle X-ray scattering. The observed cloud points show a change with temperature in the limit of solubility of the homopolymers in the block copolymer, which has an ordered, microdomain structure at low temperatures but a disordered, homogeneous structure at high temperatures. The observed solubility limits at low temperatures turn out to be greater, by an order og magnitude, than the prediction based on an earlier block copolymer theory. The phase diagram, constructed on the basis of the light and X-ray scattering data, is rich in features and resembles the complex phase diagrams often observed with binary metal alloys. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 26, 1983
- Accession Number
- ADA124929
Entities
People
- R. J. Roe
- W. C. Zin
Organizations
- University of Cincinnati