SYNTHESIS AND PROPERTIES OF POLYETHERETHERKETONE POLYDIMETHYLSILOXANE BLOCK COPOLYMERS

Polyetheretherketone‐polydimethylsiloxane (PEEK–PDMS) block copolymers were synthesized from the condensation of dimethylamino terminated PDMS and hydroxy terminated PEEK oligomers in 1‐chloronapthalene. Yields for block copolymers synthesised from low molecular weight PDMS oligomers were good but yields were significantly reduced when higher molecular weight PDMS oligomers were used. This was related to the limited solubility of higher molecular weight PDMS in the reaction solvent. Differential scanning calorimetry (DSC) studies indicated that phase separation of the block copolymers occurred at very short segment length (M̄n < 4000). A depression in the crystallinity of both the PEEK and PDMS phases in the block copolymer was observed. Thermogravimetric analysis (TGA) studies indicated that the PEEK–PDMS block copolymers displayed insufficient thermo‐oxidative stability to be melt‐processed successfully in PEEK based blends. Copyright © 1990 John Wiley & Sons, Inc.