Nanocomposites with Biodegradable Polycaprolactone Matrix IvicaJanigova´, 1 Frantis ˇekLednicky´, 2 Daniela Jochec Mos ˇkova´, 1 IvanChoda´k * 1 Summary: Biodegradable polymer/clay nanocomposites and/or composites based on poly(e-polycaprolactone) (PCL) were prepared by conventional melt mixing. Three kinds of clays, organomodified Cloisite 15A and Cloisite 10A with different ammonium cations located in the silicate gallery and unmodified Cloisite with Na cations were used for composites preparation. The degree of dispersion of silicate layers in the matrix was determined by X-ray diffraction and transmission electron microscopy. Oscillatory rheological measurements were used for characterization of the physical network formed by the filler. The presence of intercalated and exfoliated structures were observed for the composites PCL/Cloisite 15A and PCL/Cloisite 10A, indicating that nanocomposite structure was formed. Changes of viscoelastic properties to more solid-like behavior, especially in the low frequency range were explained by formation of silicate network structure, which can be detected by modified Cole-Cole plots. Keywords: melt mixing; nanocomposites; organoclay; polycaprolactone; silicate network structure Introduction Biodegradable plastics-based materials (BDPs) are considered to be a viable alternative for conventional commodity plastics because of both convenient dealing with plastics waste and in most cases production from renewable resources. However, to meet the target of partial substitution of commodity plastics by BDPs, mainly in packagings, more versatile properties of the materials must be reached to cover the full range of properties provided by commodity oil – based plastics. Additionally, a decrease in the price of basic materials must be dealt with as well. Besides looking for new plastics, either from natural renewable resources or pro- duced by synthesis, both goals can be addressed by appropriate physical and/or chemical modification of currently pro- duced BDPs. From this point of view, application of various fillers is an obvious and straight forward approach. However, the selection of fillers is limited because of requirements of standards, e.g. ISO 14855, defining the maximal content of all non- biodegradable components to be below 5 wt % if the material should be declared as ‘‘biodegradable’’ (the abovementioned standard is even more specific regarding the additional requirements). Therefore, two ways seem to be acceptable, first, to use biodegradable cheap organic fillers, e.g. wood flour, or various organic fibers such as flax and cotton [1,2] or, alternatively, an application of nanofillers where even one percent of the additive can affect the properties of the composite significantly. [3] Number of papers has been focused on preparation and characterization of biode- gradable composites and nanocomposites using inorganic particulate fillers, especially clays. [3–11] From this point of view, layered silicates have been broadly investigated, mainly with polycaprolactone or polylactic acid as a polymeric matrices. [3] Polycaprolac- Macromol. Symp. 2011, 301, 1–8 DOI: 10.1002/masy.201150301 1 1 Polymer Institute, Slovak Academy of Sciences, 842 36 Bratislava, Slovak Republic Fax: (þ421) 2 54775923; E-mail: Ivan.Chodak@savba.sk 2 Institute of Macromolecular Chemistry AS CR, 160 06 Prague, Czech Republic Copyright ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com