Ultraviolet-stabilized polycarbonate

A maximum flexural stress of 9,500 psi is assumed for polycarbonate. This conservative stress value should account for degradation in ultraviolet stabilized polycarbonate exposed to long term solar exposure. While more research is required in this area, it is reasonable to expect at least a ten year useful life for ultraviolet stabilized polycarbonate. A Young s modulus of 345,000 psi and a Poisson s ratio of 0.38 are also assumed for polycarbonate. 

Figures 2 through 9 are design charts for ultraviolet stabilized polycarbonate under blast load. Charts are provided for pane thicknesses of 1/4, 3/8, 1/2, and 1 inch for pane areas up to 25 ft at pane aspect ratios (pane length to width ratios) of 1.00, 1.50, 2.00 and 4.00. The charts relate the peak experienced blast overpressure capacity, B, for convenient pane dimensions across the spectrum of encountered blast durations. Depending on the orientation of the window to the charge, the blast overpressure may either be incident or reflected. The pane dimensions (measured across the span from the gasket centerline) peak blast capacity at 1000 msec, B, static frame design pressure, r, and the required bite are printed to the right...

Hydroxy-4 -methylphenyl) benzotria-zole ( Tinuvin P ) n. A non-toxic crystalline powder with high thermal stability, an ultraviolet absorber for polystyrene, acrylics, PVC, polyesters, and polycarbonates. 

Polycarbonate was the first amorphous engineering polymer to be commercialized, and it possesses an enviable combination of performance attributes. Clearly, PC has the most advanced combination of properties such as impact resistance, ductility, clarity, dimensional stability, inherent ignition resistance, high-temperature resistance, rigidity, and creep resistance. On the other hand, the weaknesses of PC lie in its solvent resistance (organics), abrasion resistance, ultraviolet (UV) resistance (limited), notch sensitivity, and hydrolytic stability (limited). 

Blending two or more polymers offers yet another method of tailoring resins to a specific application. Because blends are only physical mixtures, the resulting polymer usually has physical and mechanical properties that lie somewhere between the values of its constituent materials. For instance, an automotive bumper made from a blend of polycarbonate resin and thermoplastic polyurethane elastomer gains rigidity from the polycarbonate resin and retains most of the flexibility and paintability of the polyurethane elastomer. For business machine housings, a blend of polycarbonate and acrylonitrile-butadiene-styrene (ABS) copolymer resins offers the enhanced performance of polycarbonate flame retardance and ultraviolet (UV) stability at a lower cost. 

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