Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates

A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polyp...

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Bibliographic Details
Published in:Soft matter 2016-01, Vol.12 (1), p.77-86
Main Authors: Santos, R. M, Vilaverde, C, Cunha, E, Paiva, M. C, Covas, J. A
Format: Article
Language:English
Subjects:
Cycloaddition
Dispersion
Electrical conductivity
Electrical resistivity
Graphite
Melts
Nanostructure
Rheometers
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Summary:A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene- graft -maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity. Preparation of polymer composites with as-produced and chemically functionalised graphite nanoplates: analysis of nanoparticle agglomerate dispersion and re-agglomeration upon relaxation.
ISSN:1744-683X
1744-6848
DOI:10.1039/c5sm01366f