Tensile strength measurements have been made on coated fused silica fibers at gage lengths up to 50 m. At gage lengths between 0.04 and 10 m, the average strength is essentially constant at about 5 GN/m2 (700 ksi). At gage lengths greater than 20 m the length dependence becomes important and by 50 m the strength has decreased to about 2 GN/m2 (300 ksi). The minimum strength recorded in the testing of samples taken continuously from a length of 1031.6 m was 0.43 GN/m2 (64 ksi). A ’’weakest link’’ model appears to be obeyed.

synopsisColor stability in irradiated PVC may be achieved by (1) structural modification to block dehydrochlorination, (2) addition of radiation protectors, or (3) addition of radical scavengers. This study explores the latter approaches. Twenty-six compounds representing a variety of structural types were screened for their effectiveness as measured by subsequent color development. Fifteen of the compounds imparted partial or complete postirradiation stability. Possible stabilizer mechanisms are discussed.

Laser-drawn epoxy-acrylate-coated fused silica fibers (∼110 μm fiber diameter) have been produced with high and exceptionally uniform strength. When tested in 20-μm lengths, they show a single-moded Weibull distribution, (m∼25), a median tensile strength Sm of 750 ksi (5.25 GN/m2), and a coefficient of variation (ν) of about 0.04. Using the previously justified ’’weakest link’’ model, this predicts Sm∼600 ksi (4.2 GN/m2) for l-km gauge lengths. The measured strength of a 1680-m-long fiber (i.e., the minimum strength found in testing 84 20-m lengths) is 620 ksi (4.35 GN/m2). The capability of drawing kilometer lengths of fibers with strengths of this magnitude and uniformity is extremely important for the production of optical fiber cables.

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Antioxidant additives in polyethylene films have been shown to diffuse to the surface where they are subsequently lost, exposing the polymer to oxidation. Compatibility of antioxidants with polyethylene may be increased by use of silane coupling agents. In this study, three approaches to antioxidant modification are examined: (1) bonding antioxidant directly to silicon, (2) coupling the silane to an antioxidant hydroxyl function, and (3) dissolving antioxidants in silanes. All three approaches are shown to be effective in reducing antioxidant loss by diffusion.