YBB 00202003-2015
YY / YBB
National Drug Packing Container (Material) Standard
Test for coefficient of mean linear thermal expansion
平均线热膨胀系数测定法
ISSUED ON. AUGUST 11, 2015
IMPLEMENTED ON. DECEMBER 01, 2015
Issued by. China Food and Drug Administration of PRC
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Test for coefficient of mean linear thermal expansion
This method specifies the method of determining the average linear thermal expansion
coefficient of elastomeric glass far below the transition temperature.
This method is applicable to the determination of the average linear thermal expansion
coefficient of medical glasses of different materials.
Definition
(1) Average linear thermal expansion coefficient α (t0; t)
It refers to, in a certain temperature interval, the ratio of the length change of the test
product and the temperature interval and test product initial length, which is expressed
by the formula (1).
Where
t0 is the initial temperature or reference temperature, °C;
t is the actual temperature of the test product, °C;
L0 is the length of the glass test product at the temperature t0 during the test, mm;
L is the length of the test product at the temperature t, mm.
This method specifies that the nominal reference temperature t0 is 20 °C, so the mean
linear thermal expansion coefficient is expressed as α (20 °C; t).
(2) Transition temperature tg
It refers to the temperature when the glass has a dynamic viscosity of 1012.3 Pa • s, which
represents the transition of the glass from the brittle state to the viscous state, AND it
corresponds to the temperature at the intersection of the tangent line of the high
temperature portion and that of the low temperature portion of the thermal expansion
curve.
Instrumentation
(1) Device used to measure the length of the test product, in the accuracy of 0.1%.
(2) Push rod expansion instrument (horizontal or vertical), which can measure the length