fulltext.study @t Gmail

β- and γ-relaxations of low density polyethylene: Study by fluorescent probes

Paper ID Volume ID Publish Year Pages File Format Full-Text
29058 44117 2006 8 PDF Available
Title
β- and γ-relaxations of low density polyethylene: Study by fluorescent probes
Abstract

The temperatures of γ- and β-relaxation processes in low density polyethylene are studied by means of fluorescence spectroscopy. In this work, the fluorescent sensors employed, p-vinyliden derivatives of N,N-dialkylaminoaryl compounds, were adsorbed in polymer films, and their fluorescence analysed over the temperature range from −200 to 0 °C. In general, the fluorescence of the probes adsorbed in polyethylene decreases as temperature increases, as a consequence of the enhancement of the free volume fraction that favours the radiationless process of the lowest excited singlet state. Slope changes are observed in the temperature ranges −160 to −130 and −70 to −30 °C, attributed to the γ- and β-transitions, respectively. All fluorescent probes exhibit higher sensitivity at β- than at γ-relaxation. Since the former involves longer range segmental motion, and a greater decrease in rigidity of the probe surrounding allows the amino group rotation around the NCAr bond to happen in probes. The results correlated well with those obtained by means of dynamic mechanical analyses, which indicated the ability of these molecular rotors to sense the weak differences in chain mobility due to β- and γ-transitions of LDPE.

Keywords
Poly(ethylene); Relaxation processes; Fluorescent probes
First Page Preview
β- and γ-relaxations of low density polyethylene: Study by fluorescent probes
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 182, Issue 1, 20 August 2006, Pages 52–59
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us