High performance cyclic olefin copolymer (COC) membranes prepared with melt processing method and using of surface modified graphitic nano-sheets for H2/CH4 and H2/CO2 separation

2016 ◽  
Vol 109 ◽  
pp. 455-463 ◽  
Author(s):  
Merve Doğu ◽  
Nevra Ercan
2017 ◽  
Vol 34 (2) ◽  
pp. 140-159 ◽  
Author(s):  
Ali Durmus ◽  
Mine B Alanalp ◽  
Ismail Aydin

In this study, cyclic olefin copolymer/poly(ethylene- co-vinyl acetate) 90/10, 80/20, and 70/30 blends were prepared by melt processing in a twin screw extruder equipped with a cast film haul-off unit to make films. Microstructural, rheological, mechanical, and viscoelastic properties of film samples were investigated by various tests performed in scanning electron microscope, rotational rheometer, dynamic mechanical analyzer, and tensile test machine. We observed that the films exhibited characteristic immiscible “matrix–droplet” or “cocontinuous” blend morphology, depending on the sample composition. Based on the melt rheology and dynamic mechanical analyzer tests, we found that poly(ethylene- co-vinyl acetate) addition changed the viscoelastic properties of cyclic olefin copolymer such as increasing short-term creep strain and relaxation time but reducing relaxation rate in solid state. One can conclude that such effects became more pronounced by adding a compatibilizer (PE-g-MA) at 50% of poly(ethylene- co-vinyl acetate) present in the composition. We also found that poly(ethylene- co-vinyl acetate) addition into cyclic olefin copolymer reduced the Young’s modulus and yield stress and increased the strain at break for the blends.


Author(s):  
Heloise Henry ◽  
Sixtine Gilliot ◽  
Stephanie Genay ◽  
Christine Barthelemy ◽  
Bertrand Decaudin ◽  
...  

Abstract Disclaimer In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose This study evaluated the stability of diluted insulin aspart solutions (containing insulin aspart and preservatives) at their most commonly used concentration in intensive care units (1 unit/mL), in 2 container types: cyclic olefin copolymer (COC) vials and polypropylene (PP) syringes. Methods Insulin aspart solution (1 unit/mL, diluted in 0.9% sodium chloride injection) was stored for 365 days in COC vials with gray stoppers and PP syringes at refrigerated (5±3°C) and ambient temperatures (25°C ± 2°C at 60% ± 5% relative humidity and protected from light). Chemical testing was conducted monthly using a validated high-performance liquid chromatography method (quantification of insulin aspart, phenol, and metacresol). Physical stability was evaluated monthly via pH measurements, visible and subvisible particle counts, and osmolality measurements. Sterility testing was also performed to validate the sterile preparation process and the maintenance of sterility throughout the study. Results The limit of stability was set at 90% of the initial concentrations of insulin aspart, phenol, and metacresol. The physicochemical stability of 1-unit/mL insulin solutions stored refrigerated and protected from light, was unchanged in COC vials for the 365-day period and for 1 month in PP syringes. At ambient temperature, subvisible particulate contamination as well as the chemical stability of insulin and metacresol were acceptable for only 1 month’s storage in PP syringes, while insulin chemical stability was maintained for only 3 months’ storage in COC vials. Conclusion According to our results, it is not recommended to administer 1-unit/mL pharmacy-diluted insulin solutions after 3 months’ storage in COC vials at ambient temperature or after 1 month in PP syringes at ambient temperature. The findings support storage of 1-unit/mL insulin aspart solution in COC vials at refrigerated temperature as the best option over the long term. Sterility was maintained in every condition. Both sterility and physicochemical stability are essential to authorize the administration of a parenteral insulin solution.


2019 ◽  
Vol 10 (41) ◽  
pp. 5578-5583 ◽  
Author(s):  
Takumitsu Kida ◽  
Ryo Tanaka ◽  
Koh-hei Nitta ◽  
Takeshi Shiono

The increase of aggregation number in a star-shaped cyclic olefin copolymer was succeeded by using a triazine-based secondary amine, which caused a drastic change in physical properties without changing the thermal properties.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1908
Author(s):  
Hai Li ◽  
Sooman Lim

Self-polarized piezoelectric devices have attracted significant interest owing to their fabrication processes with low energy consumption. Herein, novel poling-free piezoelectric nanogenerators (PENGs) based on self-polarized polyvinylidene difluoride (PVDF) induced by the incorporation of different surface-modified barium titanate nanoparticles (BTO NPs) were prepared via a fully printing process. To reveal the effect of intermolecular interactions between PVDF and NP surface groups, BTO NPs were modified with hydrophilic polydopamine (PDA) and hydrophobic 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) to yield PDA-BTO and PFD-BTO, respectively. This study demonstrates that the stronger hydrogen bonding interactions existed in PFD-BTO/PVDF composite film comparative to the PDA-BTO/PVDF composite film induced the higher β-phase formation (90%), which was evidenced by the XRD, FTIR and DSC results, as well as led to a better dispersion of NPs and improved mechanical properties of composite films. Consequently, PFD-BTO/PVDF-based PENGs without electric poling exhibited a significantly improved output voltage of 5.9 V and power density of 102 μW cm−3, which was 1.8 and 2.9 times higher than that of PDA-BTO/PVDF-based PENGs, respectively. This study provides a promising approach for advancing the search for high-performance, self-polarized PENGs in next-generation electric and electronic industries.


2009 ◽  
Vol 210 (9) ◽  
pp. 728-735 ◽  
Author(s):  
Filippo Donati ◽  
Andrea Pucci ◽  
Laura Boggioni ◽  
Incoronata Tritto ◽  
Giacomo Ruggeri

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