Degradation studies radiation

Thermal degradation studies of EB-cured terpolymeric fluorocarbon rubber [430] by nonisothermal thermogravimetry in the absence and presence of cross-link promoter TMPTA reveal that thermal stability is improved on radiation and more so in the presence of TMPTA. Initial decomposition temperature, maximum decomposition temperature and the decomposition... 

A radioactivity detector is used to measure radioactivity in the HPLC eluent, using a flow cell. The detection principle is based on liquid scintillation technology to detect phosphors caused by radiation, though a solid-state scintillator is often used around the flow cell [17,31]. This detector is very specific and can be extremely sensitive. It is often used for conducting experiments using tritium or C-14 radiolabeled compounds in toxicological, metabolic, or degradation studies. 

Although it is well established that polyisobutylene degrades under radiation, the main-chain scission radicals were never observed as primary radicals in any of these ESR studies. A possible explanation is that the two free radicals formed by chain scission are unable to migrate from the reaction site. The two end-group radicals are then likely to react with each other by either recombination or disproportionation. 

Getoff N (1991) Radiation- and Photoin-duced Degradation of Pollutants in Water. A. Comparative Study, Radiat. Phys. Chem. 37, No. 5/6 673-680. 

Figure 3. Schematic of the carborane modified PDMS system used for the radiation degradation study.

Bowmer and Bowden75 studied the radiation degradation of poly-2-methyl-l-pentene sulfone and found that at low radiation doses the S02/olefin ratio is 2 1, however at high doses this ratio is decreased and is close to unity. Thus the oligomerization of the olefin, which is the cause for the discrepancy between G(S02) and G(olefin), appears to be reversible. 

Early in the 1950s, Stacey was successful in his negotiations to have a 60Co source of y-rays installed in his laboratory. Then, in collaboration with Barker and Bourne, a series of investigations of the effects of y-radiation on saccharides was started. Both polymer formation from simple sugars and the degradation of polysaccharides were studied. 

The effect of °Co y-ray irradiation on the mechanical properties, surface morphology, and fractography of blends of plasticized PVC and thermoplastic copolyester elastomer, Hytrel (E.I. Du Pont de Nemours Company, Inc., Wilmington, Delaware), have been studied by Thomas et al. [445]. Radiation has two major effects on the blend cross-linking of the Hytrel phase and degradation of PVC phase. Both effects are found more prominent at higher radiation dose. 

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