ISO 19935-2-2020 pdf free.Plastics — Temperature modulated DSC.
This document establishes a method for measurement of specific heat capacity, c., using temperaturemodulated differential scanning calorimetry.Normative references:The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references,only the edition cited applies.Forundated 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 principlesISO 19935-1, Plastics —Temperature modulated Dsc — Part 1: General principles.ISo 80000-5,Quantities and units — Part 5: Thermodynamics.
For the purposes of this document, the terms and definitions given in lSO 472,ISO 11357-1,IS0 19935-1and Iso8oooo-5 apply.
Principles of determination of specific heat capacity with temperaturemodulated Dsc
The use of temperature modulated DSC is advantageous for the measurement of specific heat capacitynot only outside the region of a transition, because it does not require a stable baseline to achieve highaccuracy.The measurement of specific heat capacity is only based on the amplitude of the modulatedheat flow rate signal.Assuming the linear response theory, the input of multiple frequencies or random pulses as a modulatedheat source are analysed with the procedures in the ISO 19935-1.An example is shown in Annex D.
Temperature control of the modulated differential scanning calorimeter Specifications of temperature control required for temperature modulated DSC are added as follows.a)Capability to vary temperature periodically, or stepwise, or by an input of a pulse sequence with an amplitude, typically in the range of (+0,1 to 2,0) K, and a frequency, typically down to 10 mHz,superimposed on the underlying rate, typically less than 3 K/min.b) Depending on the relation of the underlying scanning rate βg to the amplitude of sample temperature profile T;o (where w the angular frequency) four cases of scanning rates are distinguished.1) Quasi-isothermal mode,β = 0. If β = 0, heat capacity can be measured as function of time, e.g. during chemical reactions like curing or during crystallization.All other calorimetricmethods measure heat capacity as function of temperature only.2) For other modes, such as Txo >Bo.TAo<Bo, and TRo = Bo, refer to lSo 19935-1.c)Any mode of temperature modulation specified in ISO 19935-1 can be used.ISO 19935 pdf download.