Preparation and Extrusion Processing of Modified Polyetherimides with Enhanced Heat Resistance

The work reports the synthesis and study of thermal, mechanical and processing properties of copolyetherimides that contain rigid-chain segments of commercially available dianhydrides. It is shown that incorporating rigid segments into the macromolecular chains increases the glass transition temperature and the thermo-oxidative stability of the polymers, but is accompanied by a decrease in melt flow and a partial deterioration of mechanical properties. As a result of analyzing the experimental data, a composition with an optimal overall balance of properties was identified; it exhibits heat resistance 15–20°C higher than the original unmodified polyetherimide while retaining mechanical properties and a melt flow index at an acceptable level. A key outcome of this work is the successful extrusion processing of the developed copolyetherimide into pellets without significant thermo-oxidative degradation, thereby preserving its mechanical properties. The obtained data confirm the prospects of a method of copolymerization with rigid-chain dianhydrides for creating structural polyetherimides with an extended temperature range and indicate the broad application potential of the developed materials.