Radiation Processing of Elastomers
The chapter provides introduction to radiation processing of solid state materials, using commercially available sources of ionizing radiation, i.e., radio-isotopic and/or accelerated electron beam installations. Dosimetry is described as the method of co
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Abstract The chapter provides introduction to radiation processing of solid state materials, using commercially available sources of ionizing radiation, i.e., radioisotopic and/or accelerated electron beam installations. Dosimetry is described as the method of controlling progress of changes in irradiated material. Distribution of doses in irradiated material is described, allowing proper processing of polymers. Basics of radiation chemistry of polymers is explained, in particular of elastomers. Radiation-induced crosslinking is most interesting reaction, but it can be accompanied by undesired phenomena like chain scission. Specific phenomena like energy transfer occur in radiation processing; therefore, composites of elastomers with components of different radiation characteristics may show unexpected results. Examples of selected cases are described in details. Comparisons between traditional methods of crosslinking with these using ionizing radiation allow consideration of introduction of the latter into industrial praxis.
1 Introduction Application of high energy chemistry in processing of elastomers consists in the supply of specific energy, which, in contrary to thermal energy effects, changes the position of electrons in the outer shell of atoms in the molecule. Particularly important is the abstraction of the electron from the outer orbital, leading to ionization and subsequent chemical reactions. High energy chemistry is that branch of chemistry which applies a physical source of energy to achieve reactions of chemical compounds with the medium and between compounds. There are different high energy chemical effects, but in processing of elastomers, only the Z. P. Zagórski (&) E. M. Kornacka Centre for Radiation Research Institute of Nuclear Chemistry and Technology, PL-03-195 Warsaw, Poland e-mail: [email protected]
P. M. Visakh et al. (eds.), Advances in Elastomers I, Advanced Structured Materials 11, DOI: 10.1007/978-3-642-20925-3_13, Springer-Verlag Berlin Heidelberg 2013
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radiation chemistry approach, discussed in the chapter, can be quantified perfectly by precise dosimetry of applied and really absorbed ionizing radiation. Confrontation of deposited energy with products of irradiation allows exact definition of the radiation yield, i.e. relation between delivered energy and resulting change of chemical energy and achieved effects. Basics of radiation chemistry and radiation processing by ionizing radiation are rather far from chemical technology and conventional processing; therefore a detailed approach is presented. It is needed for understanding of mechanisms and/ or to find a common language with specialist of irradiation devices and technologies collaborating with rubber industry. The knowledge of basics is useful both in research and development and in the application of acquired procedures or patents. Radiation chemistry is a multidisciplinary field, but is most properly considered as a part of physical chemistry. Certainly it is not a pa
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