Modification of physiochemical properties in polycaprolactone based nanocomposites by the incorporation of PVA-modified ZnO nanoparticles

Nowadays attentions were drawn over development of biodegradable polymers to reduce the use of fossil fuels [1]. Polycaprolactone (PCL) is a hydrophobic, biodegradable aliphatic polyester with crystallinity about 50% that can be synthesized from crude oil via the ring opening polymerization of caprolactone monomers [2]. Inorganic-organic hybrid nanocomposites (NCs) have attracted more attention because they combine rigidity and high stability of inorganic nano-fillers with flexibility, ductility, dielectric and easy processability of organic matrix [3]. In this paper, nanocomposite films of polycaprolactone (PCL)/ZnO-PVA were prepared by casting/solvent evaporation method. For this purpose, ZnO nanoparticles (NPs) were first modified with poly(vinyl alcohol) (PVA), at room temperature by ultrasound irradiation method. Then, PCL/ZnO-PVA NCs were obtained by addition of various weight percentages (2, 4 and 6 wt%) of ZnO-PVA into the PCL matrix, under vigorous stirring and subsequent ultrasonic irradiation (Figure 1). The structural characterization of the NC films was carried out using transmission electron microscopy (Figure 2) and X-ray diffraction. It was found that relative changes in the peaks were observed, as the concentration of filler was increased. In addition, embedding the NPs into PCL exhibited a reduction in thermal stability of NCs as compared to the pure PCL. Tensile tests for the prepared films with different NP loadings showed that the tensile strength of the NCs have significantly improved compared with pure PCL.