Monitoring of Carbon Fiber/Polyamide Composites Processing by Rheological and Thermal Analyses

The use of continuous carbon fiber reinforced thermoplastic composites in the aerospace and automotive fields has increased due to their high performance. The hot compression molding process for the manufacture of the composites has attracted much interest due mainly to the high rate of production and quality of the finished parts. This work involves the use of rheological and thermal analyses for the optimization of the processing parameters related to the manufacture of carbon fabric/polyamide 6 and 6/6 by hot compression molding. The results show that the most adequate processing temperatures to be used in the hot compression molding are 250°C and 290°C for polyamides 6 and 6/6, respectively. The loss moduli value (G″) from DMA increased with the increment of the carbon fiber content in the glass transition temperatures, due to the reinforcement contribution. Therefore, the glass transition temperatures of all samples remained constant. The use of the established parameters based on the DSC, DMA, and rheological analyses favored the manufacture of composites with a homogeneous distribution of reinforcement and matrix as observed through optical microscopy analyses.

Keywords:

• Rheological properties
• Thermoplastic composites
• Polyamides
• Dynamic mechanical analysis

ACKNOWLEDGMENTS

The authors thank FAPESP (projects no. 98/07439-6 and 02/01288-3) and CNPq (project no. 303528/2003-6) for the financial support; South America Rhodia Polyamides, Massaferro Ltd. Hexcel, in the name of Edmundo Ortiz, for the raw material supplying and Dr. Bernd Lauke, Dr. Roland Vogel, and MSc. Lukasz Figiel from the Institute of Research Polymer (IPF), Dresden, Germany for the profitable contributions.