Chitosan filler effects on the experimental characterization, spectroscopic investigation and thermal studies of PVA/PVP blend films

Structural, optical, thermal and morphological studies were performed for pure PVA/PVP (50/50) blend and PVA/PVP blend filled with different concentrations of chitosan upto 40 wt% using casting method. The prepared films were investigated by different techniques. All techniques demonstrate the complexation between chitosan and the polymers blend. There were some changes in the IR absorption bands position and its intensities. UV-vis analysis revealed intensity of the shoulder around 273-280 nm increase with increasing chitosan content. Differential scanning calorimetry (DSC) showed thermal stability of the product samples and that has improved after filling chitosan increases. Scanning electron microscope (SEM) images of different concentrations of films revealed that large crystals characteristic of chitosan were also frequently present, when chitosan content increase upto 20 wt%, rough surfaces and crystalline structures are the dominant features. The X-ray diffraction (XRD) showed that the incorporation of chitosan into the polymeric matrix causes decreasing in the crystallinity degree of the samples and this indicates the complexation between the filler and the polymers blend. Thermogravimetric analysis (TGA) is used to study the samples in the temperature range of 30-500 degrees C. Figures show typical TGA thermograms of weight loss as a function of temperature for the present system. (C) 2010 Elsevier B.V. All rights reserved.