Electron-beam radiation

The anaerobic reaction of sulfur dioxide with aqueous ammonia produces a solution of ammonium sulfite [10192-30-0]. This reaction proceeds efficientiy, even with a gas stream containing as Httie as 1 wt % sulfur dioxide. The sulfur dioxide can be regenerated at a high concentration by acidulation or by stream stripping of the ammonium sulfite solution, or the sulfite can be made to precipitate and the ammonia recovered by addition of lime (243). The process can also be modified to produce ammonium sulfate for use as fertili2er (244) (see Fertilizers). In a variant of this process, the use of electron-beam radiation cataly2es the oxidation of sulfur dioxide in the presence of ammonia to form ammonium sulfate (245). 

Campbell, F.J. and Brenner, W., Curing high performance structural adhesives by electron-beam radiation. Nav. Eng. J., June, p. 160 (1982). 

Parameters/Units Used in Electron Beam Radiation-Induced... 

Ic E, Kottapalli B, Maxim J and Pillai SD. 2007. Electron beam radiation of dried and nuts to reduce yeast and mold bioburden. J Food Prot 70(4) 981-985. 

To conduct such an experiment using electron beam radiation is more tedious, since the absorption cross section of organic materials to electrons is... 

Figure 5. Inverse number average molecular weight vs dose of PMMA exposed to electron beam radiation.

Exposure of resist materials to electron beam radiation results in dose deposition throughout the thickness of the film for films of nominal l- m... 

PBS (Figure 30) is an alternating copolymer of sulfur dioxide and 1-butene. It undergoes efficient main chain scission upon exposure to electron beam radiation to produce, as major scission products, sulfur dioxide and the olefin monomer. Exposure results first in scission of the main chain carbon-sulfur bond, followed by depolymerization of the radical (and cationic) fragments to an extent that is temperature dependent and results in evolution of the volatile monomers species. The mechanism of the radiochemical degradation of polyolefin sulfones has been the subject of detailed studies by O Donnell et. al. (.41). 

Figure 41. A plot of sensitivity to Mo (5.4k) x-ray radiation and 20 kV electron beam radiation for several resists. EPB is epoxidized polybutadiene, P(GMA-EA) is a copolymer of glycidyl methacrylate and ethyl acrylate (COP), PGMA is poly (glycidyl methacrylate), PBS is poly (butene-1 -sulfone), FBM-1 is poly (2,2,3,3-tetrafluoropropyl methacrylate), P(MMA-MA) is a copolymer of methyl methacrylate and methacrylic acid, PMMA is poly (methyl methacrylate). (Reproduced with permission from Ref. 56J...

The first example of resist relief image formation in the absence of a wet developing step was reported by Bowden and co-workers in 1974 60). These workers reported that exposure of certain poly (olefin sulfones) to electron beam radiation resulted in spontaneous relief image formation. If the films were cast thin enough and the substrates were heated, it was possible to produce clean images in the resist films by exposure alone, thereby avoiding a wet development step. 

Films of polyphthalaldehyde, sensitized by cationic photoinitiators, have been imaged at 2-5-mJ/cm in the deep ultraviolet (DUV) (see Section 3.10), at 1 pC/cm (20 kV) electron beam radiation and at an unspecified dose of Al-A x-ray radiation. The ultimate utility of this "self-developing" resist system will depend upon its efficacy as an etch barrier. It seems clear that such materials would not serve as adequate etch masks for... 

The electron beam radiation process is practically free of waste products, and therefore is no serious environmental hazard. 

Laminating adhesives generally bond clear laminate plastic films. As long as the films are clear, the adhesive can be cured by UV energy if they are opaque, electron beam radiation is a better choice. 

In the past, electron beam radiation was applied to produce PSA exclusively however, recent improvements in UV curing technology (precise UV dose control, suitable photoinitiators) permit UV to be used to produce pressure-sensitive adhesives. PSA formulations can vary in consistency from low-viscosity liquids up to solids melting at 80°C (176°F). Therefore, applications may vary from screen printing to roll coating to melt extrusion. Coat weights for most PSA materials vary from 1 to 10 g/m. ... 

Two-sided irradiation of a wire by electron beam. (Radiation Processing of Polymers (Singh, A., and Silverman, J., Eds.), Carl Hanser Publishers, p. 82 (1992). With permission from Carl Hanser Publishers.)... 

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