Thermo-mechanical behaviour of thermoplastic composite laminates with thermal energy storage/release capability

Multifunctional thermoplastic composites with thermal energy storage/release properties were produced by using a glass fabric, a polyamide 12 (PA12) matrix and two different phase change materials (PCMs), i.e. a microencapsulated paraffin wax and a carbon nanotubes shape stabilized paraffin. The melt flow index of the matrices (i.e the PA12/PCM blends) decreased with the PCM amount, while differential scanning calorimetry (DSC) tests highlighted that for the matrices with microcapsules, the melting enthalpy was about the 70% of the theoretical value, because of the fracture of some microcapsules during the compounding process. On the other hand, paraffin leakage and/or degradation in matrices with shape stabilized wax determined a considerable drop of the melting enthalpy. For all the compositions of the matrices, glass fabric reinforced laminates showed similar fiber and void volume contents, except for that with the highest amount of shape stabilized wax. Mechanical behaviour of the resulting composites was only marginally impaired by PCM introduction, while a more important decrease of the stiffness, of the failure properties and of the interlaminar shear strength was registered in the shape-stabilized wax systems.