EFFECT OF DIMETHYLDICHLOROSILANE ON THE OXYGEN PERMEATED THROUGH A SILOXANE-BASED POLYURETHANE IONOMER

The oxygen permeated through the film made by a polyurethane (PU) iono mer is demonstrated to be a siloxane-based polyurethane ionomer by inf rared spectra. For siloxane-based polyurethane ionomer molecules in an aqueous solution, the surface tension was found to decrease slightly with an increase in the concentration of dimethyldichlorosilane (DMDCS ) but to increase slightly with an increase in the ratio of NCO to OH. Owing to the increased phase volume of siloxane-based polyurethane io nomer molecules resulting from the hydrogen bonding effect and/or inte rmolecular interaction in the aqueous solution, the number-average par ticle sizes of these ionomer molecules increase considerably with an i ncrease in the DMDCS concentration and the NCO/OH ratio, respectively. More importantly, the volume of the oxygen permeated through the film was found to be larger for the film made by the PU ionomer molecule w ith 0.02% (by weight) DMDCS than for the film made by the PU ionomer m olecule without DMDCS. Our experimental results also suggest that the use of DMDCS in preparing siloxane-based polyurethane ionomers does su bstantially raise the amount of oxygen diffusing into the film made by these ionomer molecules. (C) 1997 John Wiley & Sons, Inc.