Enhanced Thermal Stability of Biodegradable Poly(3-hydroxybutyrate)/Layered Silicate Nanocomposites

Biodegradable polymers featuring ecological advantages for sustainable development have attracted a lot of attention in the recent years [1]. In this direction, poly(3-hydroxybutyrate) (PHB) is one of the most promising biopolymers. It is a biodegradable and biocompatible, linear, aliphatic polyester produced by different types of micro-organisms. However, its poor thermal stability at temperatures slightly higher than its melting point restricts the application field of PHB.

Addition of nanoparticles such as nanoclays to form nanocomposites has provided the means to improve polymer performance including thermal stability [2]. In the present work, various loadings of montmorillonite organically modified (C18MMT) by octadecylamine were dispersed in PHB using a micro-exruder/-compounder. Contsant nitrogen flow during nanocomposite preparation prevented thermal decomposition of the matrix. The effect of clay content on the composite's morphology was studied by X-ray diffraction (XRD). The hybrid material's thermal characteristics were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TGA). According to the results, polymer chains intercalated into the silicate galleries expanding the interlayer distance. It was also found that an increase of the organomodified clay content significantly delays the decomposition rates of the polymer.

Acknowledgements

This work was supported by the Region of Western Macedonia (Greece) through the PEP grant with MIS 105545 to I. Z.

References

1. Ikada, Y. and Tsuji, H., Macromol. Rapid. Commun., 24 (2003) 457.

2. Marras, S.I., Zuburtikudis, I., Panayiotou, C., Eur. Polym. J., 43 (2007) 2191.