Radiation chemistry

Radiation chemistry is a branch of chemistry . It deals with chemical and biochemical reactions that are triggered by ionizing radiation . This differs from nuclear chemistry , which deals with the synthesis and reactions of radioactive elements themselves. The reactions are usually highly complex, since the irradiated substance unselectively absorbs the absorbed radiation energy and radiation-chemical primary reactions occur at the same time. Secondary and subsequent reactions follow with the formation of more or less stable reaction products.

There are a considerable number of different sources of radiation, from ⁶⁰ Co sources (γ-rays) to electron accelerators [accelerated electrons (β-rays)].

Classification

A distinction is made between

direct radiation chemical processes (end products are formed stoichiometrically from the primary products)
indirect radiation chemical processes (end products are not derived from the primary products)
radiation-induced processes (a primary product induces the start of a radical chain reaction )

application

Electron beams are used for cross-linking of plastics used for. B. for networking cable and wire insulation made of polyethylene (PE), EP rubber or silicone rubber . Radiation crosslinking is also used industrially as a pre-crosslinking of tire components ( innerliner ), in the production of adhesive tapes and in the crosslinking of thermoplastics . The use of high-energy rays to crosslink polymers has several advantages over crosslinking under the influence of peroxides :

Carried out at room temperature
no crosslinking agent is required.

On the other hand, networking with electron beams has the disadvantages of high investment costs and the need for expensive radiation protection measures.

history

The blackening of a photographic plate by radiation emitted by uranium ores was the first known radiation-chemical reaction; it was discovered in 1895 by Wilhelm Conrad Röntgen .

literature

Adolf Heger: Technologie der Strahlenchemie von Polymers , Akademie-Verlag Berlin 1990, ISBN 3-05-500200-8

Individual evidence

↑ ^a ^b Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, pp 1349-1350.
↑ Sebastian Kotzenburg, Michael Maskus, Oskar Nuyken: Polymers - Synthesis, Properties and Applications , Springer Spectrum, 2014, p. 406, ISBN 978-3-642-34772-6 .
^ Fritz Röthemeyer, Franz Sommer: Kautschuktechnologie , Carl Hanser Verlag Munich Vienna, 2nd edition, 2006, pp. 324–329, ISBN 978-3-446-40480-9 .

[ABC_Chemie-1] Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, pp 1349-1350.

[Kotzenburg-2] Sebastian Kotzenburg, Michael Maskus, Oskar Nuyken: Polymers - Synthesis, Properties and Applications , Springer Spectrum, 2014, p. 406, ISBN 978-3-642-34772-6 .

[Röthemeyer-3] Fritz Röthemeyer, Franz Sommer: Kautschuktechnologie , Carl Hanser Verlag Munich Vienna, 2nd edition, 2006, pp. 324–329, ISBN 978-3-446-40480-9 .