Effect of thermal stretching on properties of poly (arylene ether nitrile)/aramid staple fiber composites.

Semi‐crystalline poly (arylene ether nitrile) (PEN) with outstanding thermal stability and mechanical properties are expected to be used in structural materials. Increasing the crystallinity of PEN helps improve the processability of the materials as well as the thermal and mechanical properties of the products. In present work, the comprehensive properties of PEN composites are improved by the introduction of aramid staple fiber combined with hot stretching method. The effects of aramid fiber content and hot stretch multiplicity on the properties of the composite were investigated. The result shows that when the mass fraction of aramid fiber (AF) powder is 0.3% (PEN/AF3), the composites have the best overall performance, including thermal and mechanical properties. In addition, when the tensile ratio was 300% (PEN/AF3‐300), the properties of the samples are greatly improved, with the crystallinity increasing to 36.1%, the thermal decomposition temperature of 5% (Td5%) increasing by 10°C, and the tensile strength increasing to 195.40 MPa, which is 87.34% higher than that of the non‐thermal tensile composites. Therefore, this work provides a technical route for the preparation of high performance semi‐crystalline PEN composites, which is beneficial for the development of PEN applications. [ABSTRACT FROM AUTHOR]