Density and Free Volume of Poly[1-(Trimethylsilyl)-1-Propyne] Dense Films for Bioethanol Concentration by Organophilic Pervaporation

The density of poly[(1-(trimethylsilyl)-1-propyne] (PTMSP) was measured with an extended flotation method developed in this work. The method involves comparing sample weights in air and in various wetting (methanol, ethanol) and nonwetting (water) liquids. PTMSP is considered a microheterogeneous (microporous) material. Using nonwetting liquids, a geometric density, which is a measure of thedensity of a sample as a whole, is measured. With wetting liquids, a pycnometric density related to the density of the densest regions of a microheterogeneous material is measured. The difference between these two densities is the total microporosity, which for PTMSP equals 25-29%.