J. Koenig
May 21, 2003
Citations
0
Influential Citations
30
Citations
Journal
Macromolecules
Abstract
FT-IR imaging was used to study the dissolution of symmetric diblock copolymers of poly(styrene-b-methyl methacrylate) in neutral solvents (toluene and benzene), a selective solvent (2-ethoxyethanol), a nonsolvent (cyclohexane), and mixtures of the selective solvent and nonsolvent. 2-Ethoxyethanol is a good solvent for poly(methyl methacrylate) (PMMA) but a nonsolvent for polystyrene (PS), and cyclohexane is a nonsolvent for polystyrene below 35 °C and a nonsolvent for PMMA. Copolymer samples of three different molecular weights were tested with the neutral solvents, and one molecular weight was tested with the selective solvent, nonsolvent, and solvent mixtures. FT-IR images and concentration profiles were obtained, and dissolution rates were calculated from the concentration profiles. For the neutral solvent experiments, the block copolymer dissolution mechanism was governed by either solvent diffusion, which resulted in stress cracking for low molecular weights, or disentanglement of the polymer chains...