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Irradiation Process (irradiation + process)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

On the Synthesis of Carbon Nanofibers and Nanotubes by Microwave Irradiation: Parameters, Catalysts, and Substrates

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009
Tamara Druzhinina
Abstract The microwave (MW)-assisted synthesis of one dimensional carbon systems is introduced as a promising approach to improve the speed and cost-effectiveness of the fabrication process. Improved reaction conditions are generated by direct MW heating and synthesis under advanced reaction conditions. The influence of the reaction conditions is investigated and the importance of individual process parameters on the synthesis is discussed. Temperature and pressure data recorded during the irradiation process are analyzed in detail and allow the determination of essential process parameters. This leads to improved reaction conditions, better control of the one-dimensional carbon nanosystems by tuning the catalyst materials, and allows expanding this approach to initiate the synthesis on a variety of different substrates, such as quartz glass and mica. [source]

Improved compatibility of EVOH/LDPE blends by ,-ray irradiation

ADVANCES IN POLYMER TECHNOLOGY, Issue 3 2009
Haihong Li
Abstract The change of compatibility of poly(ethylene- co -vinyl alcohol) (EVOH)/LDPE blends induced by,-ray radiation was studied. Gel extraction experiment results show that the gel fraction of blends increases linearly with the content of LDPE and reaches a maximum at 100 kGy, because neat EVOH is difficult to cross-link by irradiation. A comparison of theoretical and experimental gel contents indicates that some EVOH molecular chains enter the LDPE gel network. The peak at 3363 cm,1 on the Fourier transform infrared spectrum of pure blend gel is assigned to typical stretching of an OH bond, which indicates that a "graft" reaction occurs in the interface between EVOH and LDPE phases during the irradiation process. Mechanical property measurement results support such a structural change. The tensile strength of cross-linked blends increases with absorbed dose first, reaches a maximum value at 150 kGy, and then decreases with dose. A similar trend can also be observed in bending tests. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:192,198, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20160 [source]

Simultaneous radiation grafting of vinylbenzyl chloride onto poly(tetrafluoroethylene- co -hexafluoropropylene) films

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009
Junhwa Shin
Abstract In this study, we demonstrated that vinylbenzyl chloride (VBC), a versatile monomer with reactive a chloromethyl group could be grafted onto a poly(tetrafluoroethylene- co -hexafluoropropylene) (FEP) film without a degradation of the chloromethyl group during a simultaneous irradiation process. The effects of various irradiation conditions such as the total dose, dose rate, solvent, and VBC concentration on the degree of grafting of VBC onto a FEP film were also investigated. The prepared PVBC-grafted films were characterized using FTIR, TGA, and SEM EDX. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Precipitation of MgO·nAl2O3 in Mg-Doped ,-Al2O3 under Electron Irradiation

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2003
Kenji Kaneko
A number of nanoscale precipitates with random orientations were produced by electron irradiation of polycrystalline Mg-doped ,-Al2O3. The precipitation behavior and microstructural changes were observed using in situ high-resolution transmission electron microscopy. A ring pattern corresponding to a polycrystalline fcc structure was obtained from the region of these precipitates by selected-area diffraction, and they were identified as nonstoichiometric MgO·nAl2O3. It is believed that Al2O3 with MgO(ss) and/or MgO at the grain boundaries is effectively stabilized by the electron irradiation process, forming the fundamental structure of MgO·nAl2O3. The average size of the precipitates is about 10 nm. [source]