Irradiated plastics

Foamed plastic insulation (electron-beam-irradiated plastics)... 

Yagoubi, N. Baillet, A. Pellerin, F. Ferrier, D. Physicochemical behavior of P-irradiated plastic materials currently used as packages and medical products. Nucl. Instrum. Methods Phys. Res. 1995, 105, 340-344. 

Kim-Kang, H. Gilbert, S.G. Permeation characteristics of and extractables from gamma-irradiated and non-irradiated plastic laminates for a unit dosage injection device. Packag. Technol. Sci. 1991, 4, 35-48. 

Kim-Kang, H. Gilbert, S.G. Isolation and identification of potential migrants in gaimna-irradiated plastic laminates by using GC/MS and GC/IR. Appl. Spectrosc. 1991, 45, 572-580. 

Radical anions of c-CnF2n (n = 3-5) were generated and stabilized in y-irradiated (plastically crystalline) tetramethylsilane (TMS) and (rigid) 2-methyltetrahydrofuran (2-MTHF) matrices. The identification of radical anions was confirmed by generating the identical ESR spectra in photoionization... 

O. SismanandC. D. Bopp, Physical Properties of Irradiated Plastics, ORNL-928, Nat. Tech. Info. Ser., Operations Div. Springfield, Virginia, (1951). 

GC/FT-IR can be used for amino acid profiling with tert-butyldimethylsilyl derivatization, for the investigation of food-packaging materials, the analysis of biologically active wheat straw extracts with allopathic activity, that of cis- and traws-octadecanoic acids in margarines and of sugar units in disaccharides, for the identification of small molecular migrants extracted from y-irradiated plastic laminates or the radiolysis products of y-irradiated medazepam solution. 

Specimens used in tests were sections of cables with PVC outer coating. PVC was plasticized with DOF softener. The materials considered were exposed to the radiation and thermal aging. The samples have been irradiated at room temperature by hard gamma rays with 10 rad/sec dose power. A number of samples had been heated for long different times at 90°C. Besides a special specimens were cut out from outer coating for test on tensile machine like "Instron". The total doses of irradiation, times of heating and elongations at break obtained with "Instron" are listed in Table 1. 

The ETEE copolymer can be cross-linked by radiation (30), despite the high content of tetrafluoroethylene units. Cross-linking reduces plasticity but enhances high temperature properties and nondrip performance. The irradiated resia withstands a 400°C solder iron for 10 min without noticeable effect. 

The above-mentioned codes contain requirements for accelerated durabiUty tests. In addition, interlayer manufacturers and laminators expose test samples for several years under extreme weather conditions, eg, the Florida coast and Arizona desert. The laminated products weather extremely well, with no change in the plastic interlayer. Occasionally, clouding is noted around the edges when exposed to high humidity for long periods, but this is reversible. Colored areas of PVB laminates may fade while subjected to extensive uv/solar irradiation, which could cause an appearance issue. This has not, however, been shown to alter the laminate s other performance properties. 

Fluorescent ultraviolet lamps within an apparatus that allows condensation cycles rather than the water spray typical of xenon arc tests have been developed for plastics testing (279). The spectral cutoff wavelength of the lamps used in the apparatus determines the severity of the test. Ultraviolet B (UVB) 313 lamps allow a significant irradiance component below 290 nm, which is normally filtered out by the earth s atmosphere. Ultraviolet A (UVA)... 

J. H. Erankfort, Proceedings of Information Meeting on Irradiated Wood-Plastic Materials, Report ORNL-llC-7, Chicago, lU., 1965. 

The use of nylon-11 for powder coatings or dry coatings (qv) has been developed in response to a growing concern for the environment (44) (see Coating PROCESSES, powder technology). Electrostatic deposition allows thin films to be appHed to metal substrates. Once the powder is appHed, it must be melted and coalesced into a continuous plastic film. Eorced draft or irradiant ovens are used for fusion, and because no polymerization or cross-linkage are required for curing, coated objects can be processed quickly and air-cooled (45). 

Hollomon s ethos, combined with his ferocious energy and determination, and his sustained determination to recruit only the best researchers to join his group, over the next 15 years led to a sequence of remarkable innovations related to materials, including man-made diamond, high-quality thermal insulation, a vacuum circuit-breaker, products based on etched particle tracks in irradiated solids, polycarbonate plastic and, particularly, the Lucalox alumina envelope for a metal-vapour lamp. (Of course many managers besides Hollomon were involved.) A brilliant, detailed account of these innovations and the arrangements that made them possible was later written by Guy Suits and his successor as director, Arthur Bueche (Suits and Bueche 1967). Some of these specific episodes will feature later in this book, but it helps to reinforce the points made here about Hollomon s coneeption of broad research on materials if I point out that the invention of translucent alumina tubes for lamps was... 

Polychloroprene (neoprene) Good Discolors. The addition of aromatic plasticizers renders the material more stable to irradiation. 

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