LED thermal expansion coefficient of epoxy
resin Thermal expansion refers to the size or length of an object
increases with temperature and increasing the physical properties,
while the thermal expansion coefficient of an object in the unit
temperature changes, the material rate of change in length or volume,
which indicated that the method is (coefficient × ppm ( 10-6 ℃).
expansion coefficient is important to understand the physical nature of
the operation of the design is also forming an important parameter. the
different coefficient of thermal expansion will cause the internal
stress of polymer resin, making materials, premature rupture. plastic
expansion and contraction of metal is about 6 ~ 9 times. Coefficient of
thermal expansion as the glass transition temperature before and after
will have different values, lower than the glass transition temperature
Tg, because the more brittle material present state, it will be lower
coefficient of thermal expansion; one but above the glass transition
temperature, due to material Softening become rubber state, will become
a higher coefficient of thermal expansion. It is proposed that after
the forming operation and curing temperature near the glass transition
temperature, operating temperature is too high will easily lead to a
high coefficient of thermal expansion, thermal stress cracking gum
large produce; operating temperature is low then hardened slowly, and
inconsistent production efficiency and easy to harden enough. That the
use of thermal mechanical analyzer (TMA) test sample specimen of the
thermal expansion coefficient, Tg results of their analysis prior to
the thermal expansion coefficient of 60ppm, after the thermal expansion
coefficient of
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