| Popis: |
Multiwalled carbon nanotubes (MWNTs) were functionalized with 2-hydroxyethyl benzocyclobutene (BCB-EO) through a Diels-Alder cycloaddition reaction. The functionalized MWNTs were utilized for the surface initiated ring opening (ROP) catalyzed and anionic polymerization of ε-caprolactone (ε-CL) and ethylene oxide (EO), respectively. The kinetics of the ROP of ε-CL was monitored through thermogravimetric analysis (TGA) which revealed that the polymerization proceeds very fast as compared to that of EO and that both polymerizations could be controlled with time. 1H NMR, Raman and FTIR spectroscopy, TGA, DSC, and transmission electron microscopy (TEM) were employed for the characterization of these polymer/CNT hybrids. DSC results showed that a remarkable nucleation effect is produced by MWNTs that reduced the supercooling needed for crystallization of both PεCL and PEO. Furthermore, the isothermal crystallization kinetics of the grafted PεCL and PEO was substantially accelerated compared to the neat polymers. The strong impact on the nucleation and crystallization kinetics is attributed to the covalent MWNT-polymer bonding. © 2009 Wiley Periodicals, Inc. |
