Crosslinking and Radiation Effects in Some Natural and Synthetic Rubbers

1957 ◽  
Vol 30 (1) ◽  
pp. 27-41 ◽  
Author(s):  
A. Charlesby ◽  
D. Groves
Keyword(s):  
Radiation Dose ◽  
Natural Rubber ◽  
Radiation Effects ◽  
Main Chain ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Physical Technique ◽  
Chemical Agents ◽  
Natural And Synthetic

Abstract When subjected to atomic energy radiation certain polymers crosslink, a process which is equivalent to vulcanization, but occurs without the admixture of extraneous chemical agents. Other polymers degrade by main chain fracture, a process which occurs at random throughout the molecule, and is different from thermal or ultraviolet degradation. Methods available for detecting crosslinking in irradiated polymers, include those based on solubility and swelling which have been used to study the effect of high energy radiation on a number of natural and synthetic rubbers. The polymers investigated include natural rubber, polychloroprene, polyisobutylene, polybutadiene, and thioplasts, as well as some copolymers. The results show the degree of crosslinking to be proportional to radiation dose, and to be reduced by the presence of styrene or acrylonitrile units in copolymers. Possible applications of this physical technique of linking molecules are discussed briefly.

scholarly journals Physics of intense, high energy radiation effects.

2011 ◽  
Author(s):  
Harold Paul Hjalmarson ◽  
E. Frederick Hartman ◽  
Rudolph J. Magyar ◽  
Paul Stewart Crozier
Keyword(s):  
Radiation Effects ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation

Comparison of alpha and gamma radiation effects in polyethylene

1964 ◽  
Vol 277 (1370) ◽  
pp. 348-364 ◽  
Keyword(s):  
Gamma Radiation ◽  
Radiation Effects ◽  
Main Chain ◽  
High Energy ◽  
The Other ◽  
High Energy Radiation ◽  
Polyethylene Films ◽  
Subsequent Exposure ◽  
The Difference ◽  
Thin Polyethylene

Exposure of polyethylene and paraffins to high-energy radiation produces main chain (transvinylene) unsaturation, and this rises to a maximum limiting concentration with increasing dose. On the other hand, vinylun saturation initially present diminishes on irradiation. Comparison of the effects of a- and y-irradiation of thin polyethylene films show that the initial G value for the formation of transvinylene unsaturation is not significantly affected by the l.e.t. of the radiation, but the maximum values reached differ by a factor of over 4. Similarly the decay of vinyl unsaturation is four times slower with a-radiation. The destruction of unsaturation is ascribed to the reaction of H atom s liberated by radiation with the unsaturated groups acting as a scavenger. The difference between a- and y-radiation is due to an l.e.t. effect, more H atoms being available from radiation of lower l.e.t. Estimates are made of the proportion of H atoms which escape from the tracks of the two forms of radiation. The difference is much smaller than in the case of irradiated aqueous solutions. Data are also presented on the formation of carbonyl with a- and y-radiation, both in the presence of air, an d during subsequent exposure.

scholarly journals Radiation therapy with neutrons and hydrons of the liver region using the MCNP code: المعالجة الاشعاعية بالنترونات والهدرونات لمنطقة الكبد باستخدام الكود MCNP

2021 ◽  
Vol 5 (4) ◽  
pp. 141-131
Author(s):  
Lara Kamal Jarouj, Anis Bilal, Nikola Abo Issa Lara Kamal Jarouj, Anis Bilal, Nikola Abo Issa
Keyword(s):  
Radiation Therapy ◽  
Radiation Dose ◽  
3D Model ◽  
High Energy ◽  
Radiation Doses ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Liver Region ◽  
High Depth ◽  
Tumor Area

CT images were read and a 3D model of the tumor was created in the liver area, Then the values ​​of the radiation dose in terms of the depth resulting from (photons, neutrons and protons) were estimated and studied using the code (MCNP) after entering the data into it. The value of the radiation dose in terms of depth and curvature in photons, neutrons and protons radiation therapy was studied, from our findings in the research we note that protons are the best option for radiation therapy for high-depth liver cancer of photons and neutrons due to the lower dose at entry compared to the dose absorbed in the tumor area and its ability to deliver a greater amount of dose of neutrons and photons to the tumor area. We note that the values reached are acceptable for the treatment of tumors at a depth close to the surface. As for a large-depth tumor, it is necessary to increase high-energy radiation doses deep in the tumor area by accelerating proton therapy to protect natural organs from high-energy radiation doses.

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