SYNTHESIS OF NYLON 6,6 WITH PYRENE CHAIN-END FOR COMPATI-BILIZATION WITH GRAPHITE AND IMPROVEMENT OF THERMAL AND MECHANICAL PROPERTIES

Nylon 6,6 (PA66) is valued for its mechanical strength, chemical resistance, and thermal stability. To improve its performance in applications like automotive and aerospace, it is often reinforced with graphite, which offers a high strength-to-weight ratio and thermal conductivity1-3. However, poor adhesion between graphite and the PA66 matrix limits composite performance. To address this, a pyrene-functionalized PA66 (PA66py) (Scheme 1) was synthesized via interfacial polycondensation.4-6 The pyrene end group promotes π–π stacking with graphite, enhancing filler dispersion and matrix compatibility. Composites were prepared by ball milling, aiding graphite exfoliation and uniform distribution. X-ray diffraction (XRD) showed a slight increase in graphite interlayer spacing (0.340 to 0.343 nm), indicating polymer intercalation. Thermogravimetric analysis (TGA) revealed improved thermal stability, while differential scanning salorimetry (DSC) indicated greater crystallinity in PA66py composites, unlike standard PA66, which showed disrupted crystal structures. Atomic Force Microscopy (AFM) confirmed more uniform mechanical properties and better interfacial adhesion in PA66py composites, attributed to π–π interactions. Overall, pyrene functionalization significantly enhances PA66–graphite compatibility, improving thermal, structural, and mechanical performance. This strategy is promising for high-performance, lightweight composites and is adaptable to other polymers and carbon fillers like graphene and carbon nanotubes.