Synthesis and characterization of poly(p-chloromethylstyrene) nanocomposite comprising covalently bonded carbon nanocapsules: Superiority of thermal properties to a physical blend

The present study demonstrates the synthesis of poly(p-chloromethylstyrene) (PCMS) nanocomposite containing well-dispersed carbon nanocapsules (CNC) covalently bonded to the polymer molecules and for the first time enables a comparison between this material (PCMS–CNC) and a physical blend of PCMS and CNC (PCMS/CNC). Firstly, the pristine CNC underwent a ligand-exchange reaction with ferrocene, having an exchange frequency of one Cp-Fe- for every 40–50 hexagon on the CNC surface. These Cp-Fe-CNCs were next monolithiated by sec-butyllithium and went through a nucleophilic substitution reaction with PCMS, thus forming successfully a PCMC–CNC nanocomposite with all CNCs covalently bonded to PCMS. Direct evidence for the covalent bonding of PCMS to CNC has been obtained by FTIR, Raman and NMR spectra. Morphology of PCMS–CNC nanocomposite and individual PCMS–CNC particle have been examined by AFM and TEM imagings. Having an average particle size of 45 nm, each CNC has been bonded with multiple coil-shaped PCMS and each PCMS could have been bonded only to one CNC. Covalent bonding of PCMS with CNC does not affect the photoluminescence and PCMS–CNC would provide the same optical properties as PCMS/CNC. At an identical weight composition, DSC thermograms clearly indicate that while Tg of PCMS/CNC blend is only slightly higher than pristine PCMS, Tg of PCMS–CNC is significantly higher due to the slower chain mobility caused by the tethering of PCMS to CNC.