In situ‐induced epiphytic crystallization of MC PA6 by self‐assembled nucleator and reinforcing effect

Abstract Monomer casting nylon‐6 (MC PA6), as a high‐performance engineering plastic, replaces metals to be widely applied, while further improving the mechanical properties of MC PA6 is significant for its withstanding heavy loads and increasing its range of applications. In this work, amide nucleating agent (NUDA) with good compatibility and crystal matching relationship with PA6 was firstly dissolved in ε ‐caprolactam monomer, and MC PA6‐NUDA was synthesized in situ . NUDA self‐assembled into special frameworks and induced epiphytic crystallization of PA6 to form an enhanced sheaf‐like crystal on its surface with microfibrillar structure during the parallel polymerization–crystallization process. Incorporation of appropriate content of NUDA improved the melting/crystallization point and crystallinity with decreasing grain size obviously, and advanced the crystallization process of MC PA6 mainly via reducing the nucleation potential energy and inducing the formation of crystal nuclei. As a result, the glass transition temperature increased, the tensile strength exhibited a significant 22% increase and the fracture toughness was nearly three times that of neat MC PA6. Meanwhile, deformation with many yield folds as well as stress‐whitening phenomena were observed on the impact‐fractured surfaces, presenting a ductile fracture feature, indicating reinforcing and toughening effect of NUDA on the PA6 matrix. © 2023 Society of Industrial Chemistry.