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