Radiation Crosslinking of Rubber—Effect of Additives

1958 ◽  
Vol 31 (4) ◽  
pp. 737-746
Author(s):  
D. T. Turner
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Radiation Chemistry ◽  
High Energy ◽  
Radical Mechanism ◽  
Linear Polymers ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Effect Of Additives ◽  
Free Radical Mechanism

Abstract Rubber is one of the linear polymers which may be crosslinked by high energy radiation. In this paper the effect of a range of additives on the cross-linking of rubber by pile and gamma radiation is reported. Many were found to retard crosslinking and this is of interest mechanistically and as an example of protection against high energy radiation. A major problem in radiation chemistry is the relative importance of ions, excited molecules, and free radicals. An ionic mechanism has been suggested for the crosslinking of polyethylene and both excitation transfer and free radical hypotheses of protection have been suggested in the radiolysis of polymethyl methacrylate. The adequacy of a free radical mechanism may be assessed by comparison of protective power and radical acceptance and in this work most of the additives were chosen because of their known, or reasonably inferred, reactivity towards free radicals and, in particular, of polyisoprenyl radicals.

scholarly journals Gel Dosimetry with Radio-Fluorogenic Coumarin

2018 ◽  
Author(s):  
Peter A. Sandwall ◽  
Brandt P. Bastow ◽  
Henry B. Spitz ◽  
Howard R. Elson ◽  
Michael Lamba ◽  
...  
Keyword(s):  
Free Radicals ◽  
Carboxylic Acid ◽  
Three Dimensional ◽  
High Energy ◽  
Water Radiolysis ◽  
Gel Dosimetry ◽  
Rate Dependency ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Hydroxyl Free Radicals

In radiotherapy, accurate deposition of energy to the targeted volume is vital to ensure effective treatment. Gel dosimeters are attractive detection systems, as tissue substitutes with potential to yield three-dimensional dose distributions. Radio-fluorogenesis is creation fluorescent chemical products in response to energy deposition from high-energy radiation. This report shares studies of a radio-fluorogenic gel dosimetry system, gelatin with coumarin-3-carboxlyic acid (C3CA), for the quantification of imparted energy. Aqueous solutions exposed to ionizing radiation result in the production of hydroxyl free radicals through water radiolysis. Interactions between hydroxyl free radicals and coumarin-3-carboxylic acid produce a fluorescent product. 7-hydroxy-coumarin-3-carboxylic acid has a blue (445 nm) emission, following UV to near UV (365–405 nm) excitation. Effects of C3CA concentration and pH buffers were investigated for this system. The response of the system was explored with respect to strength, type, and exposure rate of high-energy radiation. Results show a linear dose response relationship with a dose-rate dependency and no energy or type dependencies. This report supports the utility of gelatin-C3CA for phantom studies of radio-fluorogenic processes.

CORRELATION BETWEEN PHOTOCHEMISTRY AND HIGH-ENERGY RADIATION CHEMISTRY

1968 ◽  
Vol 7 (6) ◽  
pp. 695-703 ◽  
Author(s):  
GEORGE S. HAMMOND ◽  
RICHARD A. CALDWELL ◽  
JOHN M. KING ◽  
HAUKUR KRISTINSSON ◽  
DAVID G. WHITTEN
Keyword(s):  
Radiation Chemistry ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation

THE REACTION OF 2-CYANO-2-PROPYL FREE RADICALS WITH OXYGEN: 2-CYANO-2-PROPYL HYDROPEROXIDE

1960 ◽  
Vol 38 (7) ◽  
pp. 1154-1157 ◽  
Author(s):  
M. Talât-Erben ◽  
Nevzat Önol
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Hydrogen Cyanide ◽  
Elevated Temperatures ◽  
Radical Mechanism ◽  
Acetone Cyanohydrin ◽  
Experimental Conditions ◽  
Polymerization Catalyst ◽  
Free Radical Mechanism ◽  
Induced Decomposition

The reaction with oxygen of cyanisopropyl free radicals generated by the polymerization catalyst 2,2′-azobisisobutyronitrile has been investigated. In xylene, or benzene, as solvent at 55° the products identified are: (1) a new compound, 2-cyano-2-propyl hydroperoxide; (2) acetone cyanohydrin; (3) hydrogen cyanide; (4) cyanogen; (5) acetone; (6) p-methyl benzaldehyde (in xylene only); and (7) tetramethylsuccinodinitrile. The hydroperoxide is surprisingly stable; its physical constants are: b.p. 37 °C at 1 mm Hg; m.p. −9 to −8°; [Formula: see text] 1.4138; d20 1.013 g/ml. In benzene under the same experimental conditions, only a very small amount of the hydroperoxide is obtained, the principal product being acetone cyanohydrin. A free-radical mechanism is proposed. The induced decomposition of the hydroperoxide, which is important in benzene, is almost completely inhibited in the presence of xylene. The new hydroperoxide can be used as a polymerization catalyst at moderately elevated temperatures.

scholarly journals Challenges and Opportunities for CsPbBr3 Perovskites in Low- and High-Energy Radiation Detection

2021 ◽  
pp. 1290-1314
Author(s):  
Lotte Clinckemalie ◽  
Donato Valli ◽  
Maarten B. J. Roeffaers ◽  
Johan Hofkens ◽  
Bapi Pradhan ◽  
...  
Keyword(s):  
Radiation Detection ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Challenges And Opportunities

Ultrasmall Gd@Cdots as a Radiosensitizing Agent for Non-Small Cell Lung Cancer

Nanoscale ◽  
2021 ◽  
Author(s):  
Chaebin Lee ◽  
Xiangji Liu ◽  
Weizhong Zhang ◽  
M. A. Duncan ◽  
Fangchao Jiang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Cross Section ◽  
Cell Lung Cancer ◽  
High Energy ◽  
Small Cell ◽  
Small Cell Lung ◽  
High Energy Radiation ◽  
Energy Radiation

High-Z nanoparticles (HZNPs) afford high cross-section for high energy radiation and have attracted wide attention as a novel type of radiosensizers. However, conventional HZNPs are often associated with issues such...

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