INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The effect of processing technique on the clay orientation of Polycaprolactone/clay nanocomposites
Autor/es:
LEANDRO N. LUDUEÑA; ANALÍA VAZQUEZ; JOSE M. KENNY; VERA A. ALVAREZ
Lugar:
La Plata
Reunión:
Workshop; 1er Workshop de Nanoarcillas y sus aplicaciones; 2013
Resumen:
Due to environmental concerns, biodegradable polymers, such as Polycaprolactone (PCL), are receiving growing attention. The main limitation of PCL is its low stiffness regarding traditional polymers [Kunioka et al. 2007]. The mechanical performance of this material can be enhanced by the dispersion of nanometer-size inorganic particles such as clays (montmorillonite). Once the clay dispersion degree inside the polymer matrix is optimal, it can be supposed that the final properties of the nanocomposite will not further improve [Fischer 2003]. In this work we propose another route to enhance the mechanical properties which is based on the following assumptions. It has been widely demonstrated that processing techniques such as film stretching produce the alignment of the polymer chains as a consequence of the induced extensional flow. Extensional flow is also present in injection molded parts but only on the vicinity of the mold wall, which also promotes polymer chains alignment on that regions. On the other hand, there are techniques such as compression molding which do not produce extensional flow, thus, polymer chains are not preferentially aligned. The hypothesis of this study is that the extensional flow that produce polymer chains alignment can also preferentially align clay platelets improving the mechanical properties of the polymer in that direction even when the clay dispersion degree inside the matrix has been previously optimized. Based on this hypothesis, in this work the effect of processing techniques (film stretching, injection molding and compression molding) on the morphology (transmission electron microscopy TEM, X-ray diffraction), mechanical and thermal properties of PCL/clay nanocomposites was studied. It was found that the extent of clay platelets alignment is a function of the extensional flow intensity induced by the different post-extrusion techniques. Despite the fact that a polymer/clay system with optimal polymer/clay compatibility and strong clay organo-modifier processing stability was used, the mechanical properties of the nanocomposites could be further improved as a function of the clay platelets alignment.