Microstructures and mechanical properties of thermoplastic composites based on polyarylate/nylon6 islands‐in‐sea fibers

Polyarylate (PAR) fiber‐reinforced nylon6 composites are manufactured by molding uniaxially‐aligned islands‐in‐sea fibers at different temperature (190–210°C), pressure (0.69–6.89 MPa), and time (1–10 min). For the purpose, the islands‐in‐sea fibers, in which 74 PAR islands act as reinforcing microfibers and nylon6 sea part serves as a semicrystalline matrix in the thermoplastic composites, are prepared by a conjugate melt‐spinning. The tensile and dynamic mechanical properties of the thermoplastic composites are investigated by taking into account their microstructural and morphological features, which are influenced by the molding conditions, as examined by differential scanning calorimetry, 2D‐X‐ray diffraction, scanning electron microscopy, micro‐CT, and polarized optical microscopy (POM) analyses. The thermoplastic composite manufactured at 200°C and 2.07 MPa for 3 min is found to have maximum tensile strength of ∼630 MPa and initial modulus of ∼70 GPa owing to multiple synergistic effects such as high crystallinity of nylon6 matrix, good alignment of PAR microfibers, interfacial crystallization of nylon6 on the reinforcing PAR microfibers, and low porosity. The findings of this study indicate that PAR/nylon6 inland‐in‐sea fibers can be utilized effectively for manufacturing high performance thermoplastic composites for sports, automotive, and protective applications. POLYM. COMPOS., 40:E484–E492, 2019. © 2018 Society of Plastics Engineers