WCA March 2014

Figure 2 shows TGA test plots for optical fibre samples made with single coat 200 μm OD of new and commercial coatings. The results show better thermal stability of the new coating in fibre format. The weight loss results of fibre with the new coating tested isothermally at 150, 180 and 200°C are shown in Figure 3 . The comparative plot of thermal stability of 200-micron single coat fibre with new and commercial coatings is shown in Figure 4 . Under isothermal heat aging at 150°C for more than 1,000 hours, the new coating again shows superior performance. 3 New coating material fibre sample tests Attenuation temperature sensitivity was measured for temperatures of 150°C, 180°C and 200°C. Because measurements were done manually at room temperature after particular exposure to elevated tem- peratures, the measurement procedures might contribute some ‘noise’ in the test data. Results of the attenuation test at 1550nm wavelength for single mode fibres with a single layer of new coating material at several temperatures are shown in Figure 5 . Attenuation below 180°C is low and stable. The experiment at 200°C will be continued for more data. Fibre strength was measured by a tensile tester at 500mm/min with a gauge length of 0.5 metres. The mean strength, the strength at 50% failure probability in the Weibull plot, of aged fibre samples is plotted in Figure 6 . ❍ ❍ Figure 5 : Attenuation test for new material single coat optical fibre samples at 150°C, 180°C and 200°C

Single coat new material (200 micron) fibre coating weight loss at 150°C, 180°C and 200°C

Coating weight loss, %

Exposure time, hours

❍ ❍ Figure 3 : Weight loss of new coating on single coat fibre at 150°C, 180°C and 200°C

New Commercial

Coating weight loss, %

Exposure time, hours

Simultaneous TG/DTA220 in air at a heating rate of 10°C/ min. Figure 1 compares the weight loss vs temperature of the new material to a commercially available coating. The TGA of the two coatings diverge at 290°C with the new coating showing a smaller weight loss and, therefore, a higher thermal stability. The temperature at selected weight loss is listed in Table 1 . 2.2 Optical fibre samples Single-mode fibre samples were drawn with a glass cladding outer diameter (OD) of 125 μm and new material single coat OD of 200 μm. Draw conditions (draw speed and UV lamp settings) were selected to deliver a standard degree of cure of the coating materials. This coating design allows direct comparison with commercially available Corning mid-temperature fibres with a single coat design and coating OD of 200 μm. 2.3 TGA tests A dynamic TGA test was conducted in air, and the fibre specimen weight change was measured at different heating rates in a temperature range between room temperature and 600-700°C. The heating rates were 5°C/min, 10°C/min, 15°C/min, and 20°C/min during these tests. ❍ ❍ Figure 4 : Comparison of weight loss of fibre with new and commercial coating at isothermal aging at 180°C

200 micron new material fibre strength at 150°C and 180°C

❍ ❍ Table 1 : The temperatures at weight loss of 5, 10 and 20% between new and commercial coating Exposure time, hours Delta attn at 1550mm, dB/km

Commercial (°C)

Weight loss, % New (°C)

5

329 366 402

310 334 358

10 20

80

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Wire & Cable ASIA – September/October 2007 March/April 2014