نتایج جستجو برای: glassy polymers

تعداد نتایج: 77458  

2007
Wenbo Luo Wenxian Liu

Crazing is usually a precursor of the brittle fracture of glassy polymers. In this paper, an optical technique is presented to quantify the crazing dominated creep damage that occurs on a stressed transparent glassy polymeric sheet of polymethyl methacrylate (PMMA). The specimens, with various sections, are loaded for a predefined period of time under a constant load at room temperature, and th...

2009
Junqiang Liu Tae-Hyun Bae Wulin Qiu Shabbir Husain Sankar Nair Christopher W. Jones Ronald R. Chance William J. Koros

For the first time, we report the C4s’ transport properties: solubility, diffusivity, permeability in 6FDA–DAM polymer, one of most permeable glassy polymers with significant nC4 vs. iC4 selectivity. An nC4 permeability of 3.7 Barrer, and nC4/iC4 ideal selectivity of 21 was found in pure 6FDA–DAM polymer membrane. Mixed matrix films were successfully fabricated using a 6FDA–DAM as the matrix, w...

Journal: :European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences 2009
Fesia Lestari Laksmana Paul Jean Antoine Hartman Kok Herman Vromans Kees Van der Voort Maarschalk

Prediction of diffusion coefficient of polymer materials is important in the pharmaceutical research and becomes the aim of this paper. This paper bases the prediction method on the estimation of the polymer fractional free volume at different environmental conditions. Focussing on glassy polymers, the free volumes of polymer films were estimated using the model of Vrentas et al. [J.S. Vrentas,...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2011
Martin Kiemes Panayotis Benetatos Annette Zippelius

Motivated by the structure of networks of cross-linked cytoskeletal biopolymers, we study orientationally ordered phases in two-dimensional networks of randomly cross-linked semiflexible polymers. We consider permanent cross-links which prescribe a finite angle and treat them as quenched disorder in a semimicroscopic replica field theory. Starting from a fluid of un-cross-linked polymers and sm...

1996
NIKOLAOS A. PEPPAS DAVID J. AM ENDE

Release of essential oils from glassy hydrophilic copolymers of 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) was studied in a range of releasing media at 307C. The release of carvone, limonene, and eugenol was investigated using swelling-controlled release systems based on these copolymers. By changing the crosslinking ratio of the copolymers it was possible to ...

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