Investigation of poly(dimethyl siloxane) (PDMS)-solvent interactions by DSC

Low temperature DSC was used to study the state of several solvents in poly (dimethyl siloxane) (PDMS) membrane and the influence on the sorbed solvent s on PDMS crystallinity. No phase transition was detected on the DSC thermo grams until - 130 degrees C, when the solvent content in polymer is low, in dependently of the solvent nature. This suggests a dispersion of the solven ts as individual molecules in the PDMS matrix. At high solvent contents, pa rt of the solvent crystallizes. Most of the crystallized solvent melts at a temperature close to the melting point of the bulk solvent, while the rest melts at a lower temperature. The DSC thermograms also show the change in crystallinity of swollen PDMS in different solvents. The poor solvent and t he solvent of moderate power increase PDMS crystallinity due to the solvent -induced crystallization effect, while the good solvent reduces polymer cry stallinity because of the solution effect. (C) 2000 Elsevier Science B.V. A ll rights reserved.