Improved metalized polycarbonate capacitor
Modified metallized polycarbonate-film capacitor withstands 500 thermal cycles between 55 and 125 C replacing conventional devices which typically withstand 10 such cycles.
Kellerman, H. J.↗
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Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer
A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.
Hilado, C. J.↗
Solid state photochemistry of polycarbonates
The quantum yield of photoFries rearrangement in a polycarbonate film has been analyzed as a function of temperature and humidity on the basis of previously reported (Koyler and Mann, 1977) experimental data. Results indicate that in the homogeneous amorphous phase, photoFries rearrangement is a concerted process proceeding either from the pi star reversed arrow n singlet, in which case it must be subject to considerable self quenching, or from a triplet, presumably the first triplet since the lifetime of higher triplets is expected to be very short in the solid phase. If the parent excited state is the first triplet, chain scission is possibly an independent process, probably occurring from the pi star reversed arrow n singlet. Evidence of chain scission on photodegradation in the solid state includes loss of C-O and C-C bond intensities revealed in the Fourier transform infrared spectra, gel permeation chromotography elution profiles of degraded film samples dissolved in CHCl3, and a decrease in tensile strength and T sub g as photodegradation proceeds. Chain scission is apparently inhibited as photoFries products accumulate.
Gupta, A.↗
Reproducibility of polycarbonate reference material in toxicity evaluation
A specific lot of bisphenol A polycarbonate has been used for almost four years as the reference material for the NASA-USF-PSC toxicity screening test method. The reproducibility of the test results over this period of time indicate that certain plastics may be more suitable reference materials than the more traditional cellulosic materials.
Hilado, C. J.↗
Nonlinear viscoelastic characterization of polycarbonate
Uniaxial tensile creep and recovery data from polycarbonate at six temperatures and six stress levels are analyzed for nonlinear viscoelastic constitutive modeling. A theory to account for combined effects of two or more accelerating factors is presented.
Caplan, E. S.↗
Review of the NASA Voyager spacecraft polycarbonate capacitor failure incident
The premission failure of a Voyager spacecraft capacitor has prompted an investigation into the use of polycarbonate capacitors in high impedance circuits, during which capacitor failures were induced by thermal cycling together with extended periods at high temperature. Measurement of leakage path temperature coefficients indicates that there are two distinct leakage types whose mechanisms are complicated by movement within the capacitor during temperature changes. A novel system for pulse detection during capacitor burn-in and ramp testing has proven to be beneficial.
Ott, F. M.↗
Cumulative creep damage for polycarbonate and polysulfone
The literature for creep to failure cumulative damage laws are reviewed. Creep to failure tests performed on polycarbonate and polysulfone under single and two step loadings are discussed. A cumulative damage law or modified time fraction rule is developed using a power law for transient creep response as the starting point. Experimental results are approximated well by the new rule. Damage and failure mechanisms associated with the two materials are suggested.
Zhang, M.↗
Cumulative creep damage for polycarbonate and polysulfone
Creep to failure tests performed on polycarbonate and polysulfone under single and two step loadings are discussed. A cumulative damage law or modified time fraction rule is developed using a power law for transient creep response as the starting point. Experimental results are approximated well by the new rule. Damage and failure mechanisms associated with the two materials are suggested.
Zhang, M. J.↗
Reinforcing of thermoplastic polycarbonate and polysulfone with carbon fibers: Production and characteristics of UD-compound objects
The production and characteristics of the carbon fiber reinforced thermoplastics polycarbonate and polysulfone are described. The production of prepregs from defined polymer solutions is emphasized along with methods of optimizing the production of compounds. The characteristics of unidirectionally reinforced thermoplastics, such as shear strength, bending strength, and impact resistance are compared with regard to fracture behavior, the influence of intermediate layers, and the behavior under cryogenic conditions and under slightly elevated temperatures. The problem of adhesion between high strength carbon fibers and thermoplastics is examined, taking into account the effect of moisture on the shear strength and the impact resistance.
Fitzer, E.↗
Plasma-polymerized coating for polycarbonate: Single-layer, abrasion resistant, and antireflection
Plasma-polymerized vinyl trimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Post-treatment of the vinyl trimethoxy silane films in an oxygen glow discharge further improved their abrasion resistance. The coatings were characterized by elemental analysis of the bulk, ESCA analysis of the surface, transmission, thickness, abrasion resistance, haze, and adhesion. This patented process is currently used by the world's largest manufacturers of non-prescription sunglasses to protect the plastic glasses from scratching and thereby to increase their useful lifetime.
Wydeven, Theodore↗
Biaxially Stretched Polycarbonate Film For Capacitors
Report describes experiments on effects of biaxial stretching on crystal structures, dielectric properties, and sellected thermal and mechanical properties of biaxially stretched polycarbonate films. Highest stretch ratios produce highest degree of crystallinity, with single crystalline phase and distribution of crystallites more nearly isotropic than uniaxially oriented film. Electrical properties at high temperatures improved.
Yen, Shaio-Ping S.↗
Effect of structure and morphology on thermal and electrical properties of polycarbonate film capacitors
Research is reported to identify polycarbonate (PC) film characteristics and fabrication procedures which extend the reliable performance range of PC capacitors to 125 C without derating, and establish quality control techniques and transfer technology to US PC film manufacturers. The approach chosen to solve these problems was to develop techniques for fabricating biaxially oriented (BX) 2 microns or thinner PC film with a low dissipation factor up to 140 C; isotropic dimensional stability; high crystallinity; and high voltage breakdown strength. The PC film structure and morphology was then correlated to thermal and electrical capacitor behavior. Analytical techniques were developed to monitor film quality during capacitor fabrication, and as a result, excellent performance was demonstrated during initial capacitor testing.
Yen, S. P. S.↗
Internal stabilization of polycarbonate resins by two stage radiation process
A new polycarbonate copolymer resin is formed by internal generation of stabilizers bound to the polymer chain. Irradiation of a solid piece or a deoxygenated solution of the resin at a first frequency below 300 nm generates 2 to 8 mol percent of phenyl salicylate groups which are rearranged to dihydroxybenzophenone groups by irradiating the resin under oxygen excluding conditions at a second frequency from 300 to 320 nm.
Gupta, Amitava↗
Spectrographic observations of polycarbonate, polyethylene, and polyformaldehyde in a ballistic range, an arc jet, and a diffusion flame.
Photographic spectra of ablating plastics in thermodynamic environments related to species and temperatures in boundary layers
ABLATING MATERIAL↗
Spectrographic observations of polycarbonate, polyethylene, and polyformaldehyde in a ballistic range, an arcjet, and a diffusion flame.
Photographic spectra of ablating plastics in thermodynamic environments related to species and temperatures in boundary layers
SPECTROGRAPHY↗
Polyurethanes of fluorine containing polycarbonates
The polyurethane polymer prepared by reacting a hydroxy-terminated carbonate with an organic diisocyanate is examined.
Trischler, F. D.↗
Abrasion-resistant antireflective coating for polycarbonate
Following plasma-polymerization technique, treatment in oxygen glow discharge further enhances abrasion resistance and transmission. Improvement in abrasion resistance was shown by measuring percentage of haze resulting from abrasion. Coating samples were analyzed for abrasion using standard fresh rubber eraser. Other tests included spectra measurements and elemental analysis with spectrometers and spectrophotometers.
Wydeven, T. J.↗
Photochemical processes in polymeric systems. II - Photochemistry of a polycarbonate of bisphenol A in solution and in the solid phase
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Gupta, A.↗