Luminescence spectra of impure molecules and polymer matrix structure

Egorov, G. P.; Moisya, E. G.

doi:10.1002/polc.5070160418

Cited by 6 publications

(1 citation statement)

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“…1). In those (2) curve for samples loaded during five days, relaxed for one day, and subsequently subjected to the same loading; (3) same as (2), but relaxation allowed after nine days. Impurity anthracene spectra were measured using spectrometer ISP-51 at 77'K, anthracene fluorescence exited with the aid of a DRS-500 lamp with light filter l,,, = 365 nm.…”

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Structural changes in polyethylene films at small deformations

Lipatov¹,

Moisya²,

Logvinenko³

et al. 1976

J of Applied Polymer Sci

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SynopsisStructural changes in PE films at deformation 2-7% under constant load were studied by molecular probe method. It was shown that at these conditions some structural rearrangements take place which involve more than 20% of polymer volume, only 2-3% being transformed in the state of three-dimensional ordering. The most part of ordering observed was connected with two-dimensional ordering in the AC plane of molecular folding, involving tie chains near the crystallites. The effect of relaxation process during deformation on structural rearrangements in P E films was also investigated.Structural changes in semicrystalline polymers during uniaxial stretching studied by many authors yielded information concerning some general features of the phenomena involved, but in no case so far detailed was a study of structural changes accompanying small deformations reported. Moreover, since deformation processes in this range are reversible, it is usually tacitly assumed that after unloading, the initial structure of a specimen is reversible recovered. However, using the molecular probe (MP) technique in the investigation of structural changes in polymer subjected to various physical actions, we were able to discover distinct signs of structural transformations even at rather small levels of deformation, which stimulated undertaking their detailed investigation.In this paper, we present some results of investigatiom of structural changes in films from low-pressure polyethylene (PE). Film thickness was about 100 microns. As b e f~r e , l -~ anthracene (A) molecules were used as impurities, their concentration in P E being g/g. Anthracene was melted with P E at 20" above the polymer melting point in a pressform, the time of melting being about 50 min. Cooling was realized in the pressform by a natural heat transfer in three ways: down to 50°, to room temperature, and to room temperature with following heat treatment at 100° under vacuum during 1 hr. As a result of such preparations, we obtained PE films with more or less ordered initial structure. Relative elongation of specimens during 25-30 days of constant load action ranged from 2% to 7%.Absorption and/or fluorescence spectra of molecule probes in amorphous

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