Optimization of the isolation of polycarbonates from solutions,
prepared by phase-boundary polycondensation
Polimery 2000, No 2, 123
SummaryPolycarbonate (PC) precipitation (from the organic phase resulting from PC synthesis) and properties of PC isolated from a methylene chloride 10% PC solution were studied in relation to ketone, (chlorinated) hydrocarbons, and alcohols used as the precipitating solvents (nonsolvents) and water added or present in the PC solutions. Acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK) allowed to precipitate PC in a convenient bulky powder form, which was thermally stable and had the desired color. Optimum polymer solution/nonsolvent ratios were established, viz., 1:1.1 (MIBK, Me20) and 1:1.5 (MEK), to minimize the residual PC remaining in the organic phase. MIBK is preferable to acetone as nonsolvent, because PC is easier to recover and fire hazards are lesser. Water in the polymer solution was found to be inadvisable.