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Wire & Cable ASIA – September/October 2007 80 March/April 2014
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 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 3: Weight loss of new coating on single coat fibre at
150°C, 180°C and 200°C
❍
❍ Figure 4: Comparison of weight loss of fibre with new and
commercial coating at isothermal aging at 180°C
Weight loss, % New(°C) Commercial (°C)
5 329 310
10 366 334
20 402 358
❍
❍ Figure 5: Attenuation test for new material single coat optical
fibre samples at 150°C, 180°C and 200°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
200 micron new material fibre
strength at 150°C and 180°C
Coating weight loss, %
Single coat new material (200
micron) fibre coating weight loss
at 150°C, 180°C and 200°C
Exposure time, hours
Coating weight loss, %Exposure time, hours
New
Commercial