Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene-co-(acrylic acid)]

Four binary polymer blends containing poly [ethylene-co-(acrylic acid)] (PEAA) as one component, and poly(4-vinyl phenol-co-2-hydroxy ethyl methacrylate) (P4VPh-co-2HEMA) or poly(2-ethyl-2-oxazoline) (PEPx) or poly(vinyl acetate-co-vinyl alcohol) (PVAc-co-VA) or poly (vinylpyrrolidone-co-vinyl acetate) (PVP-co-VAc) as the other component were prepared and used as a matrix of a series of composite materials. These binary mixtures were either partially or completely miscible within the composition range studied and were characterized by differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). Carbon nanotubes (CNTs) were prepared by a thermal treatment of polyester synthesized through the chemical reaction between ethylene glycol and citric acid over an alumina boat. High resolution transmission electron microscopy (HRTEM) was used to characterize the synthesized CNTs. Films of composite materials containing CNTs were obtained after evaporation of the solvent used to prepare solutions of the four types of binary polymer blends. Young's moduli of the composites were obtained by thermomechanical analysis at room temperature. Only one glass transition temperature was detected for several compositions on both binary blends and the composite material matrices. Evidence of hydrogen bond formation was recorded for both miscible blends and composite materials. The degree of crystallinity and Young's moduli of the CNT-polymer composites increased compared to the single polymer blends. © 2008 Wiley Periodicals, Inc

Comparative study of the thermal and mechanical properties of nanocomposites prepared by in situ polymerization of ?-caprolactone and functionalized carbon nanotubes

As an effort to compare the influence of several types of functionalized carbon nanotubes (CNTs) upon the mechanical and thermal properties of nanocomposites prepared with a poly(?-caprolactone) (PCL) as matrix and functionalized CNTs as fillers; nanocomposites of PCL-CNTs were studied in this study. CNTs were synthesized by chemical vapor deposition using dry ethanol as the carbon source. High resolution scanning electron microscopy, high resolution transmission electron microscopy, and Raman and infrared spectroscopies were used to characterize the CNTs obtained. Four chemical synthesis routes were exploited to add different types of chemical groups onto the surface of purified CNTs. Specifically, the authors inserted: (i) N-methylpyrrolidine, (ii) carboxyl and hydroxyl, (iii) urethane, and (iv) phenylmethanol groups onto CNTs surface. Nanocomposites were synthesized by in situ polymerization of ?-caprolactone (?-CL) in presence of 1 wt% of each type of functionalized CNTs. Young's moduli of the nanocomposites prepared with N-methylpyrrolidine or carboxyl and hydroxyl functionalized CNTs are higher than the one of pure PCL, whereas all the mechanical properties of the nanocomposites containing urethane or phenylmethanol groups evaluated at the break point were higher than those of pure PCL. Thermal stability of all the nanocomposites studied improved with respect to pure PCL. � 2012 Society of Plastics Engineers