Influence of clay organic modifier on morphology and performance of poly(ε-caprolactone)/clay nanocomposites

Abstract

Two series of poly(e-caprolactone) nanocomposites with different organo-modified clays (1 to 8 wt%) were prepared by the solution casting method. Organoclays with polar (Cloisite®C30B) and nonpolar (Cloisite®C15A) organic modifier and with different miscibility with poly(e-caprolactone) matrix, were chosen. Exfoliated and/or intercalated nanocomposite’s structures were obtained by using high dilution and an ultrasonic treatment for the composite preparation. The effect of the surface modification and clay content on the morphology, mechanical and thermal properties of the nanocomposites was studied. Scanning electron microscopy excluded the formation of microcomposite. The wide-angle X-ray diffraction analysis revealed that the tendency toward exfoliated structure is higher for the Cloisite®C30B, which had better miscibility with poly(e-caprolactone) matrix. Differences in spherulites’ sizes and morphology between two series of the nanocomposites were observed by the optical microscopy performed on as-casted films. Enthalpies of fusion and degrees of crystallinity were higher for nanocomposites than for neat poly(e-caprolactone) and increase with the clay loading in both series, as a consequence of the clay nucleating effect. Decreased thermal stability of nanocomposites was ascribed to thermal instability of organic modifiers of the clays. The Halpin-Tsai model was used to compare the theoretically predicted values of the Young’s modulus with experimentally obtained ones in tensile tests.[Projekat Ministarstva nauke Republike Srbije, br. 172062]

Keywords

• biodegradable
• aliphatic polyester
• layered silicate
• solution casting