MIL-PRF-5425E
4.5.5 Flexural deformation temperature. Two test specimens shall be tested in accordance
with ASTM-D648 except that the thickness of the sample being tested shall become the width of
the specimen. Those thicknesses not in the range specified in ASTM-D648 shall be plied or
machined. The unmachined surface shall be on a side. The load shall be calculated to give a
maximum fiber stress of 264 psi (1,820 kPa). Each value shall be recorded and shall meet the
requirement in table II.
4.5.6 Mechanical properties. Tensile and elongation test specimens shall be prepared from
as received plastic sheet that is 0.500 inch (12.7 mm) or less in thickness. Plastic sheet that is
over 0.500 inch in thickness shall be machined to 0.500 inch.
4.5.6.1 Tensile strength. Five test specimens shall be tested in accordance with
ASTM-D638. Results shall meet the requirement in table II.
4.5.6.2 Elongation. Elongation shall be determined in accordance with ASTM-D638. The
mean elongation immediately before fracture shall meet the requirement in table II.
4.5.7 Ultraviolet transmittance. The spectral transmittance of a test specimen, 0.250 inch
(6.4 mm) thick, shall be determined with a monochromator having a bandwidth of 10 millimicrons
or less and a photometer having a reproducibility of ±1 percent. Results shall meet the
requirement in table II.
4.5.8 Index of refraction. Three test specimens shall be tested in accordance with the
refractometer procedure of ASTM-D542. Results shall meet the requirement in table II.
4.5.9 Luminous transmittance and haze. Three test specimens shall be examined as specified
in ASTM-D1003, procedure A or B, for luminous transmittance and haze. Specimens subjected
to weathering in 4.5.10 shall be immersed in distilled water for not longer than 10 seconds and
blotted to remove surface moisture prior to examination. Luminous transmittance and haze
results shall meet the requirements in table II.
4.5.10 Weathering properties.
4.5.10.1 Accelerated weathering. Accelerated weathering shall be conducted in accordance
with ASTM-G26 except that the duration of the test shall be 120 hours. Each test specimen shall
be visually examined for conformance to 3.5, then subjected to examinations for luminous
transmittance and haze (see 4.5.9). Separate specimens shall be subjected to the warpage
examination (see 4.5.11).
11
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business