BS ISO 19935-2:2020 pdf download – Plastics — Temperature modulated DSC Part 2: Measurement of specific heat capacity c p
This document establishes a method for measurement of specific heat capacity, c p , using temperature modulated differential scanning calorimetry.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 472, Plastics — Vocabulary
ISO 11357‑1, Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles
ISO 19935‑1, Plastics — Temperature modulated DSC — Part 1: General principles
ISO 80000‑5, Quantities and units — Part 5: Thermodynamics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472, ISO 11357‑1, ISO 19935‑1 and ISO 80000‑5 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at
— IEC Electropedia: available at
4 Symbols and abbreviated terms
4.1 Temperature modulation, T(t)
According to ISO 19935‑1.
4.2 Scanning rate
According to ISO 19935‑1.
4.3 Heat flow rate, Φ(t)
According to ISO 19935‑1.
b) Depending on the relation of the underlying scanning rate β 0 to the amplitude of sample temperature profile T A ω (where ω the angular frequency) four cases of scanning rates are distinguished.
1) Quasi–isothermal mode, β 0 = 0. If β 0 = 0, heat capacity can be measured as function of time,e.g. during chemical reactions like curing or during crystallization. All other calorimetric
methods measure heat capacity as function of temperature only.
2) For other modes, such as T A ω > β 0 , T A ω < β 0 , and T A ω = β 0 , refer to ISO 19935‑1.
c) Any mode of temperature modulation specified in ISO 19935‑1 can be used.
7 Calibration
7.1 General
According to ISO 19935‑1.
7.2 Calibration of modulation amplitude
According to ISO 19935‑1.
7.3 Calibration of phase
According to ISO 19935‑1.
8 Procedure
8.1 General
The procedures of temperature modulated DSC (setting up the apparatus, loading the specimen into  the crucibles, insertion of crucibles into the instrument, performing measurements, and removal of crucibles) shall be in accordance with ISO 11357‑1.
The experimental conditions specified for temperature modulated DSC (for example, amplitude of the modulated heat flow rate, amplitude of modulated temperature, and the frequency of the modulation superimposed on the underlying rate) to be used depend on the magnitude of the specific heat capacity to be determined.
8.2 Calculation of the specific heat capacity
Specific heat capacity is calculated as Formula (2):
c p is the specific heat capacity of the specimen, in Jg −1 K −1 ;
T A is the amplitude of sample temperature profile, in K;
Φ A is the amplitude of the periodic part of the modulated heat flow rate, in mW;
m is the mass of the specimen, in mg;
ω is the angular frequency of the modulated temperature, in rad/s; ω = 2π f, where f is the frequency in Hz;
K(ω) is the calibration constant calculated according to the definition in ISO 19953-1.
For precise measurements, ω shall be low (typically ω < 60 mrad/s), so that K(ω) becomes independent on ω.
For the case of step scan mode, Formula (1) shall be used to calculate c p .
8.3 Examples of the results
8.3.1 Modulated heat flow rate and scanning rate of modulation
Figure 1 shows a typical example of modulated temperature and scanning rate (of modulation) derived by a derivative of modulated temperature of a sinusoidal waveform for the heat flux DSC plotted vs time. The scanning rate of modulation is measured as a sinusoidal wave.
9 Precision and bias
The precision and bias of the method described are not known because interlaboratory data are not available at the time of publication.
10 Test report
The test report shall include the following information:
a) a reference to this document, i.e. ISO 19935‑2:2020;
b) type and complete identification of specimen;
c) type (heat flux or power compensated), manufacturer and model of DSC instrument used;
d) material, type and mass of crucible used;BS ISO 19935-2 pdf download.