PTC effect and structure of polymer composites based on polyethylene/polyoxymethylene blend filled with dispersed iron

Mamunya, YP; Muzychenko, YV; Lebedev, EV; Boiteux, G; Seytre, G; Boullanger, C; Pissis, P

dc.contributor.author	Mamunya, YP	en
dc.contributor.author	Muzychenko, YV	en
dc.contributor.author	Lebedev, EV	en
dc.contributor.author	Boiteux, G	en
dc.contributor.author	Seytre, G	en
dc.contributor.author	Boullanger, C	en
dc.contributor.author	Pissis, P	en
dc.date.accessioned	2014-03-01T01:26:56Z
dc.date.available	2014-03-01T01:26:56Z
dc.date.issued	2007	en
dc.identifier.issn	0032-3888	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18297
dc.subject	Iron	en
dc.subject	Polyethylene	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Electric conductivity	en
dc.subject.other	Iron	en
dc.subject.other	Plastics fillers	en
dc.subject.other	Polyethylene glycols	en
dc.subject.other	Polyethylenes	en
dc.subject.other	Polymer blends	en
dc.subject.other	Positive temperature coefficient	en
dc.subject.other	Structure (composition)	en
dc.subject.other	Thermal expansion	en
dc.subject.other	Dispersed iron	en
dc.subject.other	Percolation thresholds	en
dc.subject.other	Polymer phases	en
dc.subject.other	Temperature dependence	en
dc.subject.other	Composite materials	en
dc.title	PTC effect and structure of polymer composites based on polyethylene/polyoxymethylene blend filled with dispersed iron	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/pen.20658	en
heal.identifier.secondary	http://dx.doi.org/10.1002/pen.20658	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	The temperature dependence of resistivity, structure, and thermal expansion of composites based on polyethylene/polyoxymethylene (PE/POM) blends filled with dispersed iron (Fe) have been studied. The dependence of conductivity on filler content shows percolation behavior, with the values of the percolation thresholds equal to 21 vol% for PE-Fe, 24 vol% for POM-Fe, and 9 vol% for the filled blend PE/POM-Fe, with two-step character of the conductivity curve. The evolution of structure of the composite PE/POM-Fe demonstrates transition from polymer matrix POM-Fe, with inclusions of PE through cocontinuous phases of both POM-Fe and PE, to PE matrix, with inclusions of POM-Fe. Such a structure occurs due to localization of the filler only in one of the polymer phases, namely in POM. Measurements of the coefficient of thermal expansion alpha show the presence of two values of alpha: higher value (equal to et of PE) and lower value (equal to alpha of POM-Fe), the transition between them corresponding to the structure with cocontinuous phases. The PE/POM-Fe composites demonstrate double-positive temperature coefficient (PTC) effect, with the presence of two transitions and a plateau between them. In such a system, two contributions to the PTC effect coexist: the first contribution originates from the thermal expansion of the nonconductive PE phase with higher value of the coefficient alpha, which leads to the break of the continuity of the conductive POM-Fe phase; the second contribution originates from the break of the conductive structure of the filler inside the POM-Fe phase because of the morphological changes in the vicinity of the melting temperature of POM. The double PTC effect is explained in terms of these two processes (thermal expansion and melting). (c) 2006 Society of Plastics Engineers	en
heal.publisher	JOHN WILEY & SONS INC	en
heal.journalName	Polymer Engineering and Science	en
dc.identifier.doi	10.1002/pen.20658	en
dc.identifier.isi	ISI:000243414900004	en
dc.identifier.volume	47	en
dc.identifier.issue	1	en
dc.identifier.spage	34	en
dc.identifier.epage	42	en