Crosslinking radiation yield

Photo-crosslinking during UV-radiation, yielding intermediate products with high solubility differences between the exposed and non-exposed regions even in thick layers, and... 

If butadiene is used as a coagent, the dose for gel formation is reduced by a factor 5 [77]. It is of interest that parallel to an increase of radiation yield of crosslinking, the yield of chain sdssions inoeases, as well. For instance, for butadiene, G of cross-linking is 0.69 andG of sdsdtms isO.44 for divinyl sulphone (CH, = CHSO CH=CHj) this value is 0.46 and 1.1, respectively. From the G value it may thus be seen that the... 

Another way of modifying unsaturated PHAs in the bulk is by crosslinking of the material. This has been accomplished by either chemical reaction with sulfur or peroxides [109, 110], or by radiation curing [91, 111]. In all cases, crosslinking altered the ultimate material properties drastically, yielding a true rubbery material. The advantages of applying rubbers from crosslinked PHAs over the use of current rubbers will be elaborated in Sect. 4.5. 

The radiation chemical yields are expressed in terms of G-values. G(scission), G(s), equals the number of main chain scissions produced per 100 eV of energy absorbed and G (cross-linking), G(x), the number of crosslinks formed per 100 eV absorbed. The G-value is a structure dependent constant similar to quantum efficiency in photochemistry. 

This reaction mechanism predicts a small separation distance between the two alkyl radicals in pair determined by the proton-transfer distance. This small separation distance was thought to favor the high yield of the radiation-induced crosslinks. However, the above reaction mechanism seems not to accommodate the results of the ESE study. 

One of the most interesting problems was evaluation of quantum yield for light induced crosslinking of poly(vinyl butyral) in the presence of diphenyl sulphoxide. Mathematical treatment of the molecular changes produced in polymers by light is based on that by ionizing radiation. In our case, as the changes above the gel point were examined, the only suitable approach... 

Copolymers of 2,3-epoxypropyl methacrylate and butadiene prepared by solution free radical polymerization were tested as potential candidates for electrom negative resists.The sensitivity of the copolymers to ionizing radiation was determined with a linear accelerator.The experimental data were treated according to the Saito-Inokuti statistical theory.The calculated crosslinking yield values, G(x),were dependent an... 

---