Thermo-electrofluctuation method for studying polymer properties

Zelenev, Yu. V.; Ivanovskii, V. A.

doi:10.1016/0032-3950(90)90121-l

Cited by 1 publication

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The internal pressure ρ′ was determined according to [5]. Table 3 gives the results of estimating the physical characteristics of polymer systems of different structural organisation and chemical composition by the thermal electrical fluctuation method.…”

Section: Figurementioning

confidence: 99%

“…In this context, to analyse processes of molecular mobility, it is expedient to use methods that make it possible to carry out tests in the absence of any force fields, and that are sensitive to the appearance of as large a number of temperature transitions of the m∆T series as possible. One such method is the thermal electrical fluctuation method [5].…”

mentioning

confidence: 99%

“…A second aspect of using the thermal electrical fluctuation method for analysis of structurally inhomogeneous polymer systems is the determination of their physical properties, which is possible on the basis of measuring the mean square stress of thermal electrical fluctuations U T 2 (t, T). As shown in [5,6], U T 2 (t, T) can be written in the form…”

mentioning

confidence: 99%

See 2 more Smart Citations

Using the Thermal Electrical Fluctuation Method to Investigate Molecular Mobility in Structurally Inhomogeneous Polymer Systems

Zelenev

Ivanovskii

Valgin

2003

International Polymer Science and Technology

View full text Add to dashboard Cite

This work demonstrates the relationship between the intensity of electrical fluctuations and features of the structural organisation of polymer systems of different classes.The results of analysing processes of molecular mobility in the polymers polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), low-density polyethylene (LDPE), polytetrafluoroethylene, natural rubber, and SKMS-10 butadiene-methylstyrene rubber and in the copolymer vinylidene fluoride + tetrafluoroethylene (VDF + TFE) have been interpreted in accordance with the theory of temperature transitions in solids, according to which they can be observed after 12.5 K.An investigation was made of the dependence of the spectral density of the stress of electrical fluctuations on the frequency in the range 0.15-1.0 MHz.The thermal electrical fluctuation method was used to determine the physical quantities of polymer systems that are connected with their structural organisation: dielectric characteristics, effective dipole moment, internal pressure. The correlation was shown between the physical characteristics of PVC when modifier MBS is introduced and the thickness-related spectral density of the stresses of electrical fluctuations.Molecular mobility in polymers is due to vibrations of individual groups and fragments of macromolecules which are represented by different subsystems: the set of elements of supermolecular structures, macromolecules of identical or different length, free and combined segments, and different quasiparticles [1]. In a study of molecular motions in polymers of different structure by methods of relaxation spectrometry in wide temperature and frequency ranges it was established that the temperature values at which temperature transitions appear depend considerably on the types of force field and their strengths.With increase in the strength of the force field (as with increase in the frequency of external action), the regions of relaxation that appear are displaced towards higher temperatures, which makes it difficult to assess the true values of the temperature coefficients of the relaxation times and the effective size of the kinetic units. Furthermore, not all temperature transitions can be recorded by existing methods used to study relaxation effects in polymeric materials and systems.It is known [2][3][4] that the temperatures of the transitions in solids can be placed in the serieswhere m is an integer and ∆T = 12.5 K.Thus, in the range 0-400 K, up to 30 temperature transitions can appear. However, in real polymers no more than 10-12 are recorded. This is due firstly to the structural inhomogeneity of the polymer systems, and secondly to the insensitivity of the existing methods of relaxation spectrometry that are used for analysis.In this context, to analyse processes of molecular mobility, it is expedient to use methods that make it possible to carry out tests in the absence of any force fields, and that are sensitive to the appearance of as large a number of temperature transitions of the m∆T series as...

show abstract

Section: Figurementioning

confidence: 99%

mentioning

confidence: 99%