Epoxy chain extender grafted pyrophyllite/poly(ethylene terephthalate) composites with enhanced crystallinity and mechanical properties

Abstract The surface‐grafting modification of nano clay has become increasingly important for improving the practical application of clays. In this study, an epoxy chain extender ADR‐4468 was used to modify the surface of pyrophyllite (Prl), and the effect of ADR‐4468‐modified pyrophyllite (A‐Prl) on the properties of poly(ethylene terephthalate) (PET) and PET/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate) (PETG) composites was investigated. The modified composites were characterized by Fourier transformed infrared spectroscopy, X‐ray diffraction and TG, which proved that the A‐Prl was successfully synthesized, and the addition of ADR‐4468 did not change the crystal structure of pyrophyllite. The grafted ADR‐4468 improved the agglomeration of Prl, and some A‐Prl reached nano‐scale dispersion in PET and PET/PETG composites. The rheological properties, crystallization behavior and mechanical properties of PET and PET/PETG nanocomposites were systematically investigated. The results showed that A‐Prl was an effective nucleating agent for PET, which significantly improved the crystallization properties of PET composites. The A‐Prl also improved the comprehensive mechanical properties of PET and PET/PETG nanocomposites. In particular, the impact toughness of A‐Prl/PET/PETG composite with 1.5 wt % A‐Prl was increased by 120% compared with that of pure PET. The functional additive is expected to be used in the preparation of high‐performance and recyclable PET composites.