标准编号：ISO 6721-7:2019
中文名称：塑料 动态机械性能的测定 第7部分：扭转振动 非共振法
英文名称：Plastics — Determination of dynamic mechanical properties — Part 7: Torsional vibration — Non-resonance method
发布日期：2019-04
标准范围
This document describes a torsional, non-resonance method for determining the components of the
shear complex modulus G* of solid polymers in the form of bars or rods at frequencies typically in the
range 0,001 Hz to 100 Hz. Higher-frequency measurements can be made, but significant errors in the
dynamic properties measured are likely to result (see 10.2.1 and 10.2.2). The method is suitable for
measuring dynamic storage moduli ranging from about 10 MPa, which is typical of values obtained for
stiff rubbers, to values of about 10 GPa which are representative of fibre-reinforced plastics. Although
materials with moduli less than 10 MPa can be studied, more accurate measurements of their dynamic
properties can be made using simple shear (see ISO 6721-6) or torsional deformations of thin layers
between parallel plates.
This method is particularly suited to the measurement of loss factors greater than 0,02 and may
therefore be conveniently used to study the variation of dynamic properties with temperature and
frequency through most of the glass-rubber relaxation region (see ISO 6721-1). The availability of data
determined over wide ranges of both frequency and temperature enable master plots to be derived,
using frequency-temperature shift procedures, which display dynamic properties over an extended
frequency range at different temperatures.
NOTE Although loss factors below 0,1 can be more accurately determined using the torsion pendulum
(see ISO 6721-2), the method described in this document enables a much wider and continuous frequency range
to be covered.
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