Zobrazeno 1 - 10
of 76
pro vyhledávání: '"J Stejny"'
Autor:
Thomas Lüpke, Günter Dlubek, M. Ashraf Alam, D. Bamford, Duncan Kilburn, Tammo J. Menke, J Stejny
Publikováno v:
Macromolecular Chemistry and Physics. 207:492-502
Positron annihilation lifetime spectroscopy, differential scanning calorimetry, wide-angle X-ray scattering, and density measurements were used to systematically study the variation of the glass transition temperature Tg and the mean size ν h of hol
Autor:
S. Bornemann, A Rodriguez-Gonzalez, D. Bamford, Manfred Arnold, M A Alam, J Stejny, Günter Dlubek, B. Schade
Publikováno v:
Journal of Polymer Science Part B: Polymer Physics. 40:434-453
Positron annihilation lifetime spectroscopy (PALS), density, and differential scanning calorimetric (DSC) measurements were used to study systematically the variation of the glass-transition temperature (T g ) and the size v and number density N h of
Autor:
Ch. Hübner, D. Bamford, Günter Dlubek, Th. Lüpke, K. Petters, Mary J. Hill, J Stejny, M A Alam
Publikováno v:
Journal of Polymer Science Part B: Polymer Physics. 40:65-81
High-quality positron lifetime measurements (70 million total counts) are reported for polyethylenes (PEs) of different crystallinities (Xc = 3–82%). The specific volumes of the crystalline and amorphous phases (Vc and Va, respectively) were estima
Publikováno v:
Macromolecules. 34:8156-8159
We assess the size and shape of the free volume holes in crystalline polyethylene fibers (crystallinity ∼85%) via the measurements of confinement momenta of parapositronium trapped within these holes. The holes show considerable anisotropy and a sh
Autor:
J. Stejny, P. K. Lightfoot
Publikováno v:
Journal of Materials Science: Materials in Electronics. 12:581-586
The adhesion strength of a poly(p-xylylene) (PPX) film to a silicon wafer surface deposited from the vapor was studied using a peel test method. It was found that, within the time and the temperature range studied in this work, the adhesion strength
Publikováno v:
Macromolecules. 33:990-996
We report on the local free-volume properties in a series of commercial ethylene−vinyl acetate (EVA) copolymers ranging from PE to PVA, obtained via positron lifetime spectroscopy. The samples were characterized by DMA (dynamic mechanical analysis)
Publikováno v:
Acta Physica Polonica A. 95:521-526
Different definitions of the free volumes are discussed and related to the total specific volume and to the local free (hole) volume. Positron lifetime measurements are reported for polyethylene, polytetrafluoroethylene, and CR39-copolymers. Two long
Publikováno v:
Polymer. 39:4175-4179
Poly(decamethylene sebacate) was crystallized from solution in supercritical carbon dioxide in a high pressure optical cell. Turbidity measurements were used to monitor the crystallization process and to determine the polymer solubility as a function
Publikováno v:
Macromolecules. 31:4574-4580
The effect of cross-linking on the free-volume properties of poly(diethylene glycol bis(allyl carbonate)) networks was studied using a series of networks with progressively decreasing density of cross-links. The networks were prepared by bulk copolym
Autor:
J. Stejny
Publikováno v:
Polymer Bulletin. 36:617-621
The effect of crosslinking on the glass transition temperature and the specific volume of poly(diethylene glycol bis(allyl carbonate)) networks was studied using a series of networks with progressively decreasing density of crosslinks. The networks w