Grafting of Polymers onto Carbon Microcoil by Use of Carboxyl Groups on the Surface and Electric Properties of Conductive Composite Prepared from Silicone Rubber with the Polymer-Grafted Carbon Microcoil

Abstract

ABSTRACT:Carboxyl groups were successfully introduced on carbon microcoil (CMC) surface by the treatment with nitric acid. The carboxyl group content increased with increasing reaction time and reached to 1.34 mmol/g after 10 h. Poly(ethylene glycol) (PEG) was grafted onto the CMC surface by the reaction of carboxyl groups with terminal hydroxyl groups of PEG in the presence of condensing agent such as N,N 0 -dicyclohexylcarbodiimide or Lewis acid catalyst such as scandium (III) trifluoromethanesulfonate. Carboxyl groups on CMC surface have ability to initiate the cationic polymerization of vinyl monomers, such as isobutyl vinyl ether and N-vinylcarbazole and the corresponding polymers were grafted onto the surface. By grafting of polymers onto the surface, the entanglement of CMC was effectively destroyed and polymer-grafted CMC uniformly dispersed in good solvents for grafted polymer and silicone rubber. The inductance, capacitance, and resistance of conductive composite prepared from polymer-grafted CMC responded to acetone vapor. The inductance of the composite from polymer-grafted CMC increased in acetone vapor, and returned to initial value when it was transferred into air. The capacitance and resistance of the composite decreased in acetone vapor, and returned to initial value when it was transferred into air.

Surface Functionalization of Carbon Micro Coils and Their Selective Immobilization on Surface-Modified Silicon Substrates

“…Then the amount of oxides as COOH groups calculated from the weight loss was estimated as 1.1, 1.9, and 2 6 × 10 −3 mol/g for 7, 10, and 12 h treatments, respectively. From the titration measurement, it was reported that the amount of oxides was 1 34 × 10 −3 mol/g for CMC after nitric acid treatment of 10 h. 24 The present result is considerably consistent with the previous report. As compared to the related nanocarbon material, the amount of carboxyl groups for multiwalled carbon nanotube was 3 7 × 10 −3 mol/g after 48 h acid-treatment.…”

Growth and Properties of Carbon Microcoils and Nanocoils

“…Carboxyl group functionalized CMCs were prepared using nitric acid and then coated with poly(ethylene glycol) (PEG) or poly(isobutyl vinyl ether) (IBVE). The PEG-coated CMCs were dispersed in water and poly-IBVE-coated CMCs were well dispersed in silicone rubber [63]. Bi et al [64,65] demonstrated nickel-phosphorus (Ni-P) coating on the surface of double helical CMCs (Figure 23) using an electroless plating process to add magnetic properties.…”