Real-time micro-raman measurements on stressed polyethylene fibers. 1. Strain rate effects and molecular stress redistribution

Tarantili, PA; Andreopoulos, AG; Galiotis, C

dc.contributor.author	Tarantili, PA	en
dc.contributor.author	Andreopoulos, AG	en
dc.contributor.author	Galiotis, C	en
dc.date.accessioned	2014-03-01T01:14:06Z
dc.date.available	2014-03-01T01:14:06Z
dc.date.issued	1998	en
dc.identifier.issn	0024-9297	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12870
dc.subject	Polyethylene	en
dc.subject	Strain Rate Effect	en
dc.subject	Real Time	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Deformation	en
dc.subject.other	Microcracking	en
dc.subject.other	Molecules	en
dc.subject.other	Monitoring	en
dc.subject.other	Raman spectroscopy	en
dc.subject.other	Real time systems	en
dc.subject.other	Strain rate	en
dc.subject.other	Stresses	en
dc.subject.other	Ultrahigh molecular weight polyethylenes	en
dc.subject.other	Molecular deformation	en
dc.subject.other	Molecular stress redistribution	en
dc.subject.other	Raman band shift	en
dc.subject.other	Remote laser Raman microscopy	en
dc.subject.other	Stress field	en
dc.subject.other	Stretching mode band	en
dc.subject.other	Wavenumber shift	en
dc.subject.other	Plastic filaments	en
dc.title	Real-time micro-raman measurements on stressed polyethylene fibers. 1. Strain rate effects and molecular stress redistribution	en
heal.type	journalArticle	en
heal.identifier.primary	10.1021/ma961498l	en
heal.identifier.secondary	http://dx.doi.org/10.1021/ma961498l	en
heal.language	English	en
heal.publicationDate	1998	en
heal.abstract	The molecular deformation of ultrahigh-molecular-weight polyethylene monofilaments was monitored in real time by remote laser Raman microscopy(ReRaM). A shift to lower wavenumbers of the symmetric and asymmetric C-C stretching mode bands, was observed in agreement with previously published data. The stress or strain dependence of the Raman wavenumbers as a function of strain rate was also examined at room temperature. Furthermore, the broadening of the Raman bands as a function of applied stress or strain was investigated and compared with the wavenumber shift in each case. The Raman band shift for the asymmetric and symmetric C-C stretching modes per stress or strain was found to be only marginally affected for strain rates ranging from 10(-4) to 10(-3) s(-1). The onset of the observed dramatic decrease of the Raman wavenumbers as a function of stress or strain was directly related to the existence of two yield points. The first "yield" point at relatively low applied strain/stress is thought to be associated with the plastic flow of the amorphous part. The second "yield" point at high strain/stress is possibly associated with the initiation of microcracking, which leads to the ultimate failure of the fiber. Finally, the corresponding band broadening indicated the presence of a highly nonuniform stress field acting upon the molecules of the crystalline fraction that give rise to the broad symmetric C-C and asymmetric stretching modes. A number of structural models have been reviewed in the light of the Raman data presented here.	en
heal.publisher	AMER CHEMICAL SOC	en
heal.journalName	Macromolecules	en
dc.identifier.doi	10.1021/ma961498l	en
dc.identifier.isi	ISI:000076389300031	en
dc.identifier.volume	31	en
dc.identifier.issue	20	en
dc.identifier.spage	6964	en
dc.identifier.epage	6976	en