Effective thermal conductivity and thermal properties of phthalonitrile‐terminated poly(arylene ether nitriles) composites with hybrid functionalized alumina

A polymer‐based thermal conductive composite has been developed. It is based on a dispersion of micro‐ and nanosized alumina (Al 2 O 3 ) in the phthalonitrile‐terminated poly (arylene ether nitriles) (PEN‐ t ‐ph) via solution casting method. The Al 2 O 3 with different particle sizes were functionalized with phthalocyanine (Pc) which was used as coupling agent to improve the compatibility of Al 2 O 3 and PEN‐ t ‐ph matrix. The content of microsized functionalized Al 2 O 3 (m‐ f ‐Al 2 O 3 ) maintained at 30 wt % to form the main thermally conductive path in the composites, and the nanosized functionalized Al 2 O 3 (n‐ f ‐Al 2 O 3 ) act as connection role to provide additional channels for the heat flow. The thermal conductivity of the f ‐Al 2 O 3 /PEN‐ t ‐ph composites were investigated as a function of n‐ f ‐Al 2 O 3 loading. Also, a remarkable improvement of the thermal conductivity from 0.206 to 0.467 W/mK was achieved at 30 wt % n‐ f ‐Al 2 O 3 loading, which is nearly 2.7‐fold higher than that of pure PEN‐ t ‐ph polymer. Furthermore, the mechanical testing reveals that the tensile strength increased from 99 MPa for pure PEN‐ t ‐ph to 105 MPa for composites with 30 wt % m‐ f ‐Al 2 O 3 filler loading. In addition, the PEN‐ t ‐ph composites possess excellent thermal properties with glass transition temperature ( T g ) above 184°C, and initial degradation temperature ( T id ) over 490°C.