Synthesis and self‐assembly of polystyrene‐grafted multiwalled carbon nanotubes with a hairy‐rod nanostructure

Abstract

Polystyrene‐grafted multiwalled carbon nanotubes (PS‐g‐MWNTs) with a hairy‐rod nanostructure were synthesized by the in situ free‐radical polymerization of styrene in the presence of multiwalled carbon nanotubes (MWNTs) terminated with vinyl groups. To quantitatively study the molecular weight and composition of polystyrene (PS) chains in PS‐g‐MWNTs, PS‐g‐MWNTs were fully defunctionalized by hydrolysis. The results showed that 1 of every 100 carbon atoms in MWNTs was functionalized at the tips and outer walls of the carbon nanotubes and grafted by PS with a weight‐average molecular weight of 9800 g/mol; therefore, a uniform thin layer (ca. 8–10 nm) of a PS shell was formed on the outer wall of MWNTs. PS‐g‐MWNTs were soluble in dimethylformamide and tetrahydrofuran. The thermal stability and glass‐transition temperature of PS in PS‐g‐MWNTs were obviously increased. Nanopins were formed on the glass substrates by the self‐assembly of PS‐g‐MWNTs, and the dewetting effect between the glass substrate and PS chains covered MWNTs during the evaporation of the solution. Both the length and diameter of the nanopins increased with the solution concentration. When PS‐g‐MWNTs were compression‐molded, MWNTs were dispersed uniformly in the PS matrix and formed good networks, such as circlelike and starlike structures, because of the entanglements of hairy PS chains on MWNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3869–3881, 2006

Thermal properties and transition studies of multi-wall carbon nanotube/nylon-6 composites

“…When CNTs are added to a polymer, T g typically increases a few degrees [30,31] but may also increase a few tenth of degrees [32]. Because of its nano- After HP&HT treatment at 1 GPa and 530 K (see experimental), the T g features of the Pcomposite and nylon-6 vanished.…”

Effects of carbon nanotubes on polymer physics

“…56 Table 1 only includes changes that occur upon mixing a polymer with a nanotube and not covalently bonding a polymer to the nanotube; covalently attaching a polymer to the nanotube consistently increases the glass transition temperature of the attached polymer. 57,58 Some of the large slopes in Table 1 are due to something other than introducing a nanotube surface into a polymer. Materials created where the nanotubes are dispersed before polymerization of the monomer (termed dispersion-reaction in Table 1) could have effects on the T g due to reaction completeness, that is, nanotubes may alter the chemical reaction which in turn causes changes in conversion that will affect the glass transition temperature.…”

Recent developments concerning the dispersion of carbon nanotubes in surfactant/polymer systems by MD simulation

“…Although covalent functionalization methods have also been developed for MWCNTs [63], fewer investigations have been devoted to this type of nanotube. A number of routes to functionalized CNTs have been reported experimentally, including small molecules [64], linear polystyrene (PS) [65], hyperbranched poly (urea-urethane) [66], biodegradable poly (e-caprolactone) (PCL) [67], ionic polymers [68], and photoresponsive polyurethane containing azobenzene [69] are well soluble in water or organic solvents. In this regard, Subramanian et al [70] were utilized classical MD simulations to investigate the covalent functionalization of CNT and its interaction with ethylene glycol (EG) and water molecules.…”