Reinforcement effect of carbon nanofillers in an epoxy resin system: Rheology, molecular dynamics, and mechanical studies

Kotsilkova, R; Fragiadakis, D; Pissis, P

dc.contributor.author	Kotsilkova, R	en
dc.contributor.author	Fragiadakis, D	en
dc.contributor.author	Pissis, P	en
dc.date.accessioned	2014-03-01T01:23:01Z
dc.date.available	2014-03-01T01:23:01Z
dc.date.issued	2005	en
dc.identifier.issn	0887-6266	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16771
dc.subject	Carbon nanoparticles	en
dc.subject	Critical filler concentration	en
dc.subject	Dispersions	en
dc.subject	Dynamic mechanical properties	en
dc.subject	Epoxy resin	en
dc.subject	Molecular dynamics	en
dc.subject	Nanocomposites	en
dc.subject	Reinforcement	en
dc.subject	Relaxation	en
dc.subject	Viscoelastic properties	en
dc.subject	Viscosity	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Carbon	en
dc.subject.other	Crosslinking	en
dc.subject.other	Differential scanning calorimetry	en
dc.subject.other	Dispersions	en
dc.subject.other	Epoxy resins	en
dc.subject.other	Reinforcement	en
dc.subject.other	Viscoelasticity	en
dc.subject.other	Viscosity	en
dc.subject.other	Carbon nanoparticles	en
dc.subject.other	Critical filler concentration	en
dc.subject.other	Dynamic mechanical properties	en
dc.subject.other	Relaxation	en
dc.subject.other	Viscoelastic properties	en
dc.subject.other	Nanostructured materials	en
dc.title	Reinforcement effect of carbon nanofillers in an epoxy resin system: Rheology, molecular dynamics, and mechanical studies	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/polb.20352	en
heal.identifier.secondary	http://dx.doi.org/10.1002/polb.20352	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	The reinforcing effect of carbon nanoparticles in an epoxy resin has been estimated with different approaches based on rheology, molecular dynamics (evaluated by differential scanning calorimetry, dielectric relaxation spectroscopy, and thermally stimulated depolarization current), and dynamic mechanical analysis. Carbon particles aggregate as the volume increases and form a fractal structure in the matrix polymer. The dispersion microstructure has been characterized by its viscoelastic properties and relaxation time spectrum. The scaling of the storage modulus and yield stress with the volume fraction of carbon shows two distinct exponents and has thus been used to determine the critical carbon volume fraction of the network formation ((Phi) for the carbon/epoxy dispersions. At nanofiller concentrations greater than Phi, the overall mobility of the polymer chains is restricted in both dispersions and solid nanocomposites. Therefore, (1) the relaxation spectrum of the dispersions is strongly shifted toward longer times, (2) the glass-transition temperature is increased and (3) the relaxation strength of both the secondary (0) and primary (a) relaxations increases in the nanocomposites, with respect to the pure polymer matrix. The dispersion microstructure, consisting of fractal flocs and formed above Phi*, is proposed to play the main role in the reinforcement of nanocomposites. Moreover, the network structure and the interface polymer layer (bond layer), surrounding nanoparticles, increases the relaxation strength and slows the cooperative alpha relaxation, and this results in an improvement of the mechanical properties. (C) 2005 Wiley Periodicals, Inc.	en
heal.publisher	JOHN WILEY & SONS INC	en
heal.journalName	Journal of Polymer Science, Part B: Polymer Physics	en
dc.identifier.doi	10.1002/polb.20352	en
dc.identifier.isi	ISI:000227015500006	en
dc.identifier.volume	43	en
dc.identifier.issue	5	en
dc.identifier.spage	522	en
dc.identifier.epage	533	en