Comparative Study of the Thermal and Mechanical Properties of Nanocomposites Prepared by In Situ Polymerization of g-Caprolactone and Functionalized Carbon Nanotubes

摘要

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(s-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 etha-nol 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-meth-ylpyrrolidine, (ii) carboxyl and hydroxyl, (iii) urethane, and (iv) phenylmethanol groups onto CNTs surface. Nanocomposites were synthesized by in situ polymerization of s-caprolactone (e-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.