Structure–properties relationship in single polymer composites based on polyamide 6 prepared by in-mold anionic polymerization

• Autor(a) principal: Dencheva, Nadya Vasileva
• Data de Publicação: 2013
• Outros Autores: Denchev, Z., Pouzada, A. S., Sampaio, Ana Sofia, Rocha, A. M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/25079
• topic: Anionic polymerization; Single-polymer composites; Mechanical properties; Polymorph transitions in polyamides; X-ray scattering; Structure-properties relationship; Science & Technology

Single polymer composites (SPCs) based on polyamide 6 (PA6) were prepared by in-mold activated anionic ring-opening polymerization (AAROP) of capro- lactam in the presence of PA6 textile fibers. The influence of the reinforcing fibers content, their surface treatment, as well as of the temperature of AAROP upon the morphol- ogy, crystalline structure, and mechanical properties of the resulting SPCs was followed. The presence of oriented transcrystalline layer (TCL) on the surface of the rein- forcing fibers was demonstrated by means of microscopy methods. Its orientation and polymorph structure were determined by synchrotron wide-angle X-ray scattering. Studies on the mechanical behavior in tension of the SPCs showed a well-expressed growth of the stress at break (70–80 %) and deformation at break (up to 150–190 %) in composites with 15–20 wt% of reinforcements. The best mechanical properties were found in SPCs whose rein- forcing fibers were solvent-pretreated prior to AAROP in order to remove the original finish. In these samples a stronger adhesion at the fiber/matrix interface was proved by scanning electron microscopy of cryofractured samples. This effect was related to a thinner TCL in which the α-to-γ polymorph transition is impeded.