Manipulation ofthick-walled PEEKbushing crystallinity and modulus via instrumented compression molding

An instrumented hot compression molding apparatus was fabricated to allow real-time monitoring and precise temperature control during the compaction and consolidation of large polyether ether ketone (PEEK) products. The objective was to determine the impact of controlled variables on the properties of the molded article. Four different strategies were designed to control the mold thermal profiles. The average crystallinity in a commercial molding process is restricted due to large thermal masses with low thermal conductivity. In contrast, this research was able to reduce the crystallinity range from 33% to 6% by developing a special controlled apparatus and implementing new processing methodologies. In this study, PEEK showed a significant increase in the modulus compared to typical values measured on commercially produced analogs, and a higher degree of property uniformity. In a single commercially molded PEEK billet, compressive modulus variability was 13% at room temperature, and 21% at 225 degrees C. Properties of billets produced using the laboratory apparatus showed a reduction in variability to 2%.

Automated summary

This study successfully reduced the crystallinity range of PEEK and increased the modulus of the material by developing a special controlled apparatus and implementing new processing methodologies. The variability of the billets' properties was significantly reduced compared to commercially produced analogs using the laboratory apparatus.