Irradiated polycarbonate

Fluorescence spectra were recorded on a Shimadzu RF-1501 spectrofluorimeter. The irradiated polycarbonate samples were dissolved in dichloromethane (0.001 wt% PC in DCM). Emission spectra were recorded using an excitation wavelength of 310 nm (7). The second-order Rayleigh scattering peak (located at 622 nm) was used to scale the recorded fluorescence spectra (8). 

Fig. 22. Absorption spectrum of polycarbonate (concentration 0.51 g l-1 in chloroform, 0.5 cm cell) 1, unirradiated 2, irradiated 5 h 3, irradiated 30 h 4, irradiated 120 h 5, spectrum of the yellow product isolated after complete hydrolysis of irradiated polycarbonate [reproduced with permission from Ref. 108].

This mechanism is supported by the fact that a bright yellow substance can be isolated from the products of complete alkaline hydrolysis of irradiated polycarbonate, the ultraviolet and infrared spectra of which are very similar to those of 2,2 -dihydroxybenzophenone (see Figs. 22 and 23). This substance is most probably the dimer, with a structure similar to... 

Counting of High Energy Radiation Tracks. A computerized Image analyzer, the Cambridge Instrument model 900, was used to count the radiation tracks of the Irradiated polycarbonate samples. The measurements Include track size (diameter), track density In each field of view, roundness, sample area In each field, and total area of the sample. Samples of polycarbonates examined Included those prepared In our laboratory and neutron Irradiated samples provided by Dr. G. Tarle of University of California at Berkeley. 

Fig. 30 Distribution of absorbance in 7 ( Co)-irradiated polycarbonate for various doses and bght wavelengths (dose rate 2.55 kGy.h ). The data were taken from [03G1].

Other topics recently studied by XPS include the effects of thermal treatment on the morphology and adhesion of the interface between Au and the polymer trimethylcy-clohexane-polycarbonate [2.72] the composition of the surfaces and interfaces of plasma-modified Cu-PTFE and Au-PTFE, and the surface structure and the improvement of adhesion [2.73] the influence of excimer laser irradiation of the polymer on the adhesion of metallic overlayers [2.74] and the behavior of the Co-rich binder phase of WC-Co hard metal and diamond deposition on it [2.75]. 

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... 

During the course of this study, styrylpyridine based polyesters and polycarbonates as well as their related model compounds were synthesized and characterized by TGA, 01, and UV irradiation to determine the effect of the structure on thermal and UV stability. 

An increase of char yield is generally reflected as an improvement in oxygen index. In the styrylpyridine based polyesters and polycarbonate an intermolecular thermally induced Diels-Alder reaction has occurred through the double bond, this increased the char yield and decreased the flammability. The Fries rearrangement, as well as dimerization and isomerization, occurred simultaneously during the UV irradiation of p-VPPB, but no dimerization or isomerization occurred for p,p -BVPDPC, probably due to steric effects. 

The photochemistry of aryl carbonates and aryl carbamates is interesting, as these compounds are building blocks of polycarbonates and polyurethanes. Diphenyl carbonate (165) has been irradiated with ultraviolet (UV) light [122,123] and... 

Figure 18 Stability test carried out with two sealed DSSCs over 7000 hr of continuous illumination with visible light (polycarbonate 395-nm cutoff filter) at 1000 W/m2 light intensity. The photocurrent and voltage drop measured across an external load resistor of 10 ft are plotted as a function of irradiation time. Cell 1 (solid line) was continuously illuminated at 35°C the same for cell 2 (broken line) except that it was operated for a 700-hr period at 75°C and for 1000 hr at an open circuit. (From Ref. 153.)...

Standards used for comparators are either well documented materials (U.S.G.S. BCR-1 Basalt, NBS Orchard Leaves, NBS Bovine Liver, etc.) or are prepared in the laboratory by pipetting known quantities of elements onto high purity cellulose material. Standards are weighed into polycarbonate and packaged for irradiation in the same manner as the samples. 

Alkyd and polyester resins, epoxy compounds, phenol-formaldehyde resin, urea and/or melamine-aldehyde resin, cyclic urea resin, carbamide acid ester formaldehyde resin, ketone formaldehyde resin, polyurethane, polyvinylester, polyvinyl acetate, polyvinyl chloride and polymer mixtures, polyethylene, polystryrene, styrene mixtures and graft copolymers, polyamide, polycarbonate, polyvinyl ether, polyacrylic and methacrylic acid esters, polyvinyl flouride, polyvinylidene chloride copolymers, UV and/or electron irradiated lacquers. 

Suzuki, T., Kondo, K., Hamada, E., Ito, Y. (2001) Positron irradiation effects on positronium formation in polycarbonates during a positron annihilation experiments . Acta physica polonica A. 99, 515. 

Figure 9 Ultraviolet spectral absorption of 2 mil polymer films and spectral irradiance of sunlight. Abbreviations PVC, Polyvinyl chloride PE, polyethylene PS, polystyrene PC, polycarbonate AP, aromatic polyester PSF, polysulfone PET, poly(ethylene terephthalate) PAR, polyacrylate. Source From Ref. 16.

FIGURE 43.7 Examples of porous structures produced in thin polymeric films using various methods of irradiation and chemical treatment. (Reprinted from Apel, P., Radial. Meas., 34, 559, 2001. With permission from Elsevier.) (A) Cross section of a polycarbonate membrane with cylindrical nonparallel pore channels (B) polypropylene membrane with slightly conical parallel pores (C) polyethylene terephthalate membrane with cigar-like pores and (D) polyethylene terephthalate membrane with bow-tie pores. 

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