Positronium in solid phases of n-alkane binary mixtures

Zgardzińska, B.; Goworek, T.

doi:10.1016/j.chemphys.2015.06.002

Cited by 4 publications

(2 citation statements)

References 35 publications

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“…The behavior of alkanes and their mixtures as a function of pressure is well known [4][5][6][7]. The phase change (for example from liquid to rigid crystal) can be realized as a result of the decrease of temperature or increase of pressure.…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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

Zgardzińska

Tydda

Wawryszczuk

2017

DDF

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“…Moreover, this technique provides reliable information concerning changes in any free volumes with diameters below 2 nm up to several tens of nanometers. Its usefulness for investigation of various free spaces, which include mesopores (He et al 2013;Hill et al 2009), micropores (Kullmann et al 2010), and even intermolecular free volumes (Zgardzińska and Goworek 2015) has already been recognized.…”

Section: Introductionmentioning

confidence: 99%

Positron porosimetry study of mesoporous polymer–silica composites

et al. 2016

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The polymer-SiO 2 composites prepared using polymers with different chemical composition and porosity (i.e. XAD4, XAD16, and XAD7) as well as series of composites synthesized with different contents of silica species and at different pH were investigated. The study was conducted to compare the results of nitrogen adsorption and positron porosimetry for these three sets of samples. The possible causes of the inconsistency between the results of both methods are discussed. The impact of the chemical character of the polymer support surface on the final properties of the polymer-silica composite was found to be greater than its porosity (i.e. the shape of pores and their connectivity). Changing the SiO 2 content influences mostly the pore volume of composites. To significantly modify their pore size distribution, more than 30 wt% of silica species are required. The composite synthesized at pH 5 has the widest pore size distribution among all samples supported by XAD7. The discrepancies concerning the porosity derived with both methods are the smallest for composites where XAD7 was used as the support. This allows determination of the relation V = (3.38 V PALS -0.03) cm 3 /g, which may be useful for estimation of pore volumes corresponding to those found by nitrogen adsorption.

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Enthalpic perspective on thermodynamic equilibrium of bulk and confined liquids: A review

Khoshooei

Maham

2021

Journal of Molecular Liquids

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Positronium in solid phases of n-alkane binary mixtures

Cited by 4 publications

References 35 publications

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

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

Positron porosimetry study of mesoporous polymer–silica composites

Enthalpic perspective on thermodynamic equilibrium of bulk and confined liquids: A review

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