Filament photostability

The photostability of vitamin solutions under the influence of various light sources was studied by DeMerre and Wilson (96). The results of this study indicated that the rate of photolysis of vitamin is influenced by the intensity as well as the type of light source used. The loss in potency of vitamin B solution was about 10% for every 30 minutes of exposure to bright natural daylight of 8000 foot-candles. When the same solution was irradiated with a 300 W incandescent reflector-type filament lamp, the losses after two hours of exposure were 11% at 7000 foot-candles and 45% at 14,000 foot-candles. 

Melt Oxidation. In the absence of a morphological effect on oxidation of our series of PPH filaments, differences in their photostabilities must depend upon differences in the concentrations of UV absorbing impurities... 

Figure 3. Effects of hopper blanketing and extrusion temperature on PPH photostability. Filaments extrude into air with 20 m min 1 wind-up rate. Extruded temperature (hopper atmosphere) O, 200°C (N2) , 225°C (N2) +, 280°C (N2) A, 225°C (air) ...

Figure 5. Effect of draw atmosphere on PPH photostability. Filaments undrawn (0) or drawn X3 at 1000% min"1 at 25°C in air (+) and vacuum (A).

Slow cold drawing (X2 at 50% min"1) of commercial (Amtech) monofilament that already was highly oriented had a similar effect on photostability. After cold drawing, filament UV lifetime was 60% of that of the commercial filament, despite the presence of 0.24 wt % of P-2. 

Butola, B.S., Joshi, M. Photostability of FIDPE filaments stabilized with UV absorbers (UVA) and light stabihzers (HALS). J. Eng. Fibers Fabr. 8, 61-68 (2013)... 

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