Investigation of PCM microcapsules at various temperatures and pressures by PALS method

Zgardzińska, B.; Tydda, Maciej; Blazewicz, A

doi:10.1088/1742-6596/618/1/012028

Cited by 2 publications

(5 citation statements)

References 6 publications

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“…The measurements as a function of pressure were performed for three selected temperatures: 293 K, 298 K and 303 K. The results at 293 K were presented previously in [2]. Now we have found that the PALS parameters change similarly for all mentioned temperature.…”

Section: Resultssupporting

confidence: 56%

“…This shifts of phase transition points may suggest that the core material feels lower pressure than applied one, perhaps due to the protective role of the polymer shell. Comparing the values of lifetimes and intensities from the measurements vs. T [2] and p one can conclude that:…”

Section: Resultsmentioning

confidence: 96%

“…Above this pressure the o-Ps lifetime in the shell is constant, but the lifetime in the core is stable up to 80 MPa only. At higher pressures one can observe the shortening of the lifetime in the core material: first, faster between 80 and 125 MPa, and then slower (see [2]). The o-Ps intensity in the shell drastically increases in the range: 6-50 MPa.…”

Section: Resultsmentioning

confidence: 97%

“…Their behavior as a function of pressure seems to be important from the viewpoint of possible applications. The properties of these materials, as well as other similar microcapsules were previously investigated by PLAS technique as a function of temperature [2,3] -some general properties of microcapsules have been determined. Basing on these results we were able to state that in the microcapsules two o-Ps components are resolved.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Micro-Sized Capsules at High Pressure by PALS Method

Zgardzińska

Tydda

Wawryszczuk

2017

DDF

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The positron annihilation lifetime spectroscopy (PALS) was applied to investigate the properties of capsules composed of n-alkanes (filling material) and polymer (shell) in the broad range of pressures up to 450 MPa. These microcapsules aggregate into the grains having about 200 μm in diameter. Their properties were investigated as a function of pressure (p) at several selected temperatures: when the filling material is in liquid, rotator and solid phase. Pressure experiments were performed without gas access to the sample and in an argon atmosphere. Two o-Ps components were found, the longer-lived correspond to the filler material, and the shorter-lived one – to the shell. These components change with p; even a small pressure (6 MPa) reduces considerably the o-Ps lifetimes (τ). At 303 K the o-Ps lifetime in the core changes non-monotonically, and at 60 MPa τ is higher than at 20 MPa. The increase of pressure induces the phase changes in the filling material, and also produces the deformation of microcapsule aggregates and crash of small capsules at the grain boundary region. Internal structure of the microcapsules was observed by SEM.

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Section: Resultssupporting

confidence: 56%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of Micro-Sized Capsules at High Pressure by PALS Method

Zgardzińska

Tydda

Wawryszczuk

2017

DDF

View full text Add to dashboard Cite

show abstract

“…The positron annihilation lifetime spectroscopy (PALS) proposed here was already successfully used in numerous studies of material structure, ranging from metals to organic matter [summarized in Ref.9] and recently applied to study of microcapsules [10,11]. The method is based on the use of positronium (Ps), bound state of an electron e-and positron eþ (positron is the antiparticle of the electron), as a probe of matter.…”

Section: Experimental Methodsmentioning

confidence: 99%