LAUSR

Abstract Swelling of a commercial polymer in a binary mixture of tetraethyl orthosilicate (TEOS) and polyphenylmethyldimethyl siloxane (DC 550) has been studied. The distribution of the solvents, varying significantly in molecular weight, within the polymer structure was inferred from the obtained results. Namely, the uptake of each component depends non linearly on the ratio of their concentrations. The positron annihilation lifetime study of the microstructure of polymer-solvent complexes shows that a significant volume of the swollen polymer beads is occupied by solvent condensed in pores, which are completely filled with it. Due to a considerable difference in the volatility of TEOS and DC 550, the in situ study of the solvent removal under vacuum provides a lot of information about the structure of the polymer-solvent system. Especially interesting is the opening of pores, which occurs only at a large concentration of TEOS, as it indicates the presence of weakly bonded TEOS, which is confirmed by the thermogravimetric experiment.