New developments in polycaprolactone-layered silicate nano-biocomposites: Fabrication and properties

Abstract

In the family of synthetic biodegradable polymers, PCL, which is linear, hydrophobic, and partially crystalline polyester, is a biodegradable polymer. Its physical properties and commercial availability make it very attractive not only as a substitute for nonbiodegradable polymers of commodity applications but also as a specific plastic of medicine and agricultural areas. The main limitation of PCL is its low melting temperature (65 °C), which can be overcome by blending it with other polymers. In recent years, polymer/silicate hybrid nanocomposites have been of considerable interest as an effective method to improving polymer properties. This class of materials has improved the material properties due to the high aspect ratio and easy phase-to-phase energy transfer, even at very low filler concentration, if the filler is uniformly and completely dispersed in the host matrix. Polymer/layered silicate nanocomposites (PLSN) show a considerable enhancement of strength, modulus, gas barrier resistance, and heat distortion temperature compared to their pure polymer counterparts, even with silicate loadings as low as 3-5 wt%. Moreover, PLSN are also interesting from the fundamental point of view due to the nanoscale constraints of the filler to the polymer matrix and the ultra-large-specific interfacial area between the silicate and the polymer matrix. One kind of nanometer-size reinforcement is the montmorillonite, which is a layered silicate whose interlayer ions can be exchanged by organ ions in order to produce an increment in the interlayer spacing and to improve the polymer/clay compatibility. These improvements allow the dispersion of clay platelets to be easier. Nanocomposites of poly(e-caprolactone)/clay deserve interest because of the possible upgrading of polymer known for biocompatibility, biodegradability, and miscibility with a wide range of other polymers. There have been attempts to develop nanocomposites of PCL with layered silicates. PCL/clay nanocomposites were prepared through kind of methods. For example, in situ polymerization, melt intercalation and extrusion, and solution and casting also have used kind of silicate layers and modified clay with different their modifiers. © Springer-Verlag Berlin Heidelberg 2014.