Vapor sorption and dilation of poly[(1-trimethylsilyl)-1-propyne] in methanol, ethanol, and propanol

The sorption of alcohols in poly[(1-trimethylsilyi)-1-propyne] was first measured concurrently with the dilation of this polymer. It was shown for all the studied sorbates that there exists a characteristic threshold activity at which dilation begins. On passing from methanol to propanol, the threshold activity shifts to lower values. The examination of sorption and dilation isotherms demonstrated that the S-shaped portion of (lie sorption isotherm is completed when the threshold activity of dilation is achieved, It was suggested that this portion is attributed to the filling of polymer nanovoids. This finding offered a means of estimating the unrelaxed free volume and the effective polymer density from the sorption data,