Submitted to: Polymer Degradation and Stability
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/19/2007
Publication Date: 7/1/2007
Citation: Mohamed, A., Gordon, S.H., Biresaw, G. 2007. Polycaprolactone/polystyrene bioblends characterized by thermogravimetry, modulated differential scanning calorimetry and infrared photoacoustic spectroscopy. Polymer Degradation and Stability. 92:1177-1185. Interpretive Summary: Polymer bioblends are blends of polymers that contain at least one natural biodegradable polymer mixed with other synthetic polymers. Biodegradable polymer bioblends are of interest in the development of a variety of products for use in packaging materials, medical devices, drug delivery systems, etc. Preparation of useful polymer bioblends is possible only when the biodegradable polymers are compatible with the synthetic polymers. Compatibility can be determined by measuring the degree of intermolecular interactions between the polymers in the bioblend. In this work, the degree of interaction in polymer bioblends containing natural biodegradable polycaprolactone and synthetic polystyrene was investigated using thermogravimetric analysis, modulated differential scanning calorimetry and Fourier transform infrared photoacoustic spectroscopy. The thermogravimetric and calorimetric studies indicated that blending polycaprolactone with polystyrene results in bioblends that showed evidence of compatibility in some blends while others showed partial incompatibility. However, the infrared studies revealed the presence of weak intermolecular interactions between polycaprolactone and polystyrene polymers in the bioblends. Therefore, development of useful bioblends from these polymers is possible.
Technical Abstract: Polymer blends comprising at least one biodegradable polymer with other polymers are referred to as bioblends. Successful development of bioblends requires that the biodegradable polymers be compatible with other component polymers. One way of assessing compatibility is through the evaluation of the degree of intermolecular interactions between the component polymers. In this work, the degree of interaction in binary bioblends comprising biodegradable polycaprolactone (PCL) and polystyrene (PS) was investigated using thermogravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC) and Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). The TGA studies indicated that incorporation of PCL in PS results in thermal destabilization of PCL/PS bioblends. The MDSC studies showed that some parameters favored partial miscibility of PS in PCL, while others favored immiscibility. The FTIR-PAS spectra suggested the presence of intermolecular n-pi interactions between PCL and PS and supported the results of TGA and MDSC analyses of PCL/PS bioblends.