The effect of processing technique on the performance of PCL/clay nanocomposites

L.N. LUDUEÑA; A. VAZQUEZ; J.M. KENNY; V.A, ALVAREZ

Lyon

Simposio; Frontiers in Polymer Science, Second International Symposium; 2011

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. 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. 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 on the vicinity of the mold wall of injection molded parts 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 morfology (transmission electron microscopy, X-ray difraction), mechanical and thermal properties was studied.