Publicação
Structure–properties relationship in single polymer composites based on polyamide 6 prepared by in-mold anionic polymerization
| Resumo: | 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. |
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| Autores principais: | Dencheva, Nadya Vasileva |
| Outros Autores: | Denchev, Z.; Pouzada, A. S.; Sampaio, Ana Sofia; Rocha, A. M. |
| Assunto: | Anionic polymerization Single-polymer composites Mechanical properties Polymorph transitions in polyamides X-ray scattering Structure-properties relationship |
| Ano: | 2013 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | 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. |
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