engleski

MORPHOLOGY AND PROPERTIES OF PCL/TIX COMPOSITES

Biodegradable polymer composites attract increasing attention in recent years. The objective of our work is to combine biodegradable polymer components, polycaprolactone (PCL) and thermoplasticized starch (TPS), with different types of TiO2-based particles (TiX) which act as a biocompatible inorganic filler. These polymer systems will have tailored mechanical properties and controlled biodregradability rate, with possible applications in packaging industry or medicine. The first step made towards preparation of multicomponent biodegradable polymer systems was the study of the simple, two-component PCL/TiX (2 wt.%). These samples were used for the preliminary investigation of filler dispersion and its influence on the crystallisation kinetics, thermal, rheological and mechanical properties. Morphological measurements revealed better particle dispersion in systems with bigger TiO2 nanoparticles (TiNP2, average size ~200 nm), which is in agreement with the fact that bigger particles are subjected to higher shear forces during melt-mixing1 (Fig.1a). We also observed that smaller TiO2 nanoparticles (TiNP1, average size ~100 nm) and titanante nanotubes2 tended to form agglomerates in PCL matrix (Fig.1b). Crystallisation kinetics was determined from a series of polarized light micrographs3 showing the isothermal crystallization at 40 °C. The results (Fig.1c) showed that titanate nanotubes act as a sterical hindrance and decrease the overall rate of crystallization. Good dispersion of TiNP2 in the polymer matrix was confirmed by scanning electron microscopy. Other properties, such as overall crystallinity, rheology and microhardness of the PCL/TiX systems were the same within the experimental errors.

Biodegradable polymer composites; polycaprolactone; starch; morphology

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