Poly radiation effects

Temperature dependence (related to the temperature dependence of the conformational structure and the morphology of polymers) of the radiation effect on various fluoropolymers e.g., poly (tetrafluoroethylene-co-hexafluoropropylene), poly(tetrafluoroethylene-co-perfluoroalkylvinylether), and poly(tetrafluoroethylene-co-ethylene) copolymers has been reported by Tabata [419]. Hill et al. [420] have investigated the effect of environment and temperature on the radiolysis of FEP. While the irradiation is carried out at temperatures above the glass transition temperature of FEP, cross-linking reactions predominate over chain scission or degradation. Forsythe et al. [421]... 

Anderson, S.L., F.L. Harrison, G. Chan, and D.H. Moore II. 1990. Comparison of cellular and whole-animal bioassays for estimation of radiation effects in the polychaete worm Neanthes arenaceodentata (Poly-chaeta). Arch. Environ. Contam. Toxicol. 19 164-174. 

LOV MOLECULAR WEIGHT MODEL COMPOUNDS. The mechanisms of radiation effects on polymers are frequently investigated by studies of low molecular weight model compounds. Analysis of the chemical reactions is much easier than with high molecular weight polymers. Thus, N-acetyl amino acids can be studied as model compounds for poly(amino acid)s and hence for proteins. 

Berkowich, J., A. Charlesby, and V. Desreux Radiation effects on aqueous solutions of poly (vinyl alcohol). J. Polymer Sci. 25, 490 (1957). 

A number of investigations on radiation effects of polymers at ambient temperature have been carried out and summarized in some recent publications [38-40]. However, there are very few experimental results on cryogenic temperature irradiation of conventional polymers. Figure 5 shows the summary of early experiments on irradiation of polymers at 77 K up to y-ray dose of 2 x 106 Gy [41,42]. As is evident from Fig. 5, the candidate polymers that can be used at cryogenic temperatures are only aromatic based epoxy resins, poly-imides, and polystyrene. This means that the choice of polymers for superconducting magnets to be operated in a radiation environment is rather limited. Therefore, the intention of this chapter is to give information on the radiation tolerance of recently developed polymers. 

Fig. 10. Radiation effects on the flexural strength on pure and glass-fabric filled poly-imides irradiated at 4.9 K. (O) Spaulrad ( ) Norplex (A) Vespel...

Radiation-induced Degradation.—There have been several reports on radiation effects in polymers,288 including single crystals,287 fluoropolymers,288 polyamides,289 polysiloxanes,270 polyethylene and its copolymers,271 polypropylene,272 polyolefins,273 polystyrene and its copolymers,274 poly(vinyl chloride) and related polymers,275 rubbers,278 polysulphones and other sulphur-containing polymers,277 polycarbonate,278 nylon,279 poly(vinylpyridines),280 and wool.281... 

Dalai, S., Wenxiu, G., Radiation effects on poly(propylene) (PP)/ethylene-vinyl acetate copolymer (EVA) blends. Journal of Applied Polymer Science 2002, 86, 3420-3424. 

Gupta M.C., Deshmukh V.G., Radiation effects on poly(lactic acid). Polymer, 24, 1983, 827-830. 

Satti, A. J. Nador, F. Vitale, C. Radivoy, G. Andreucetti, N. N. Ciolino, A. E. Valles, E. M., Synthesis, Characterization, and Gamma Radiation Effects over Well-Defined Poly(vinylsiloxanes) Copolymers. J.Appl. Polym. Sci. 2012,124, 832-839. 

S.C.J. Loo, C.P. Ooi, Y.C.F. Boey, Radiation effects on poly(lactide-co-glycolide) (PLGA) and poly(l-lactide) (PLLA), Polym. Degrad. Stability 83 (2) (February 2004) 259—265. 

Vaughan AS, Sutton SJ (1995) On radiation effects in oriented PEEK. Polymer 36 1549-1554 Wang Z, Li Y, Yang J, Gou Q, Wu Y, Wu X, Liu P, Gu Q (2010) Twisting of lamellar crystals in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) ring-banded spherulites. Macromolecules 43 4441-4444... 

The theory of radiation-induced grafting has received extensive treatment. The direct effect of ionizing radiation in material is to produce active radical sites. A material s sensitivity to radiation ionization is reflected in its G value, which represents the number of radicals in a specific type (e.g., peroxy or allyl) produced in the material per 100 eV of energy absorbed. For example, the G value of poly(vinyl chloride) is 10-15, of PE is 6-8, and of polystyrene is 1.5-3. Regarding monomers, the G value of methyl methacrylate is 11.5, of acrylonitrile is 5.6, and of styrene is >0.69. 

Figure 4. Effect of radiation on the poly(ethylene terephthalate-co-2,6-naphthalene-dicarboxylate) yarns mole % of 2,6-DMN (%) 0.0 (X) 0.5 fA) 1-0 (O) 2.0 ...

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