ISO 11357-2:2013 pdf download.Plastics一Differential scanning calorimetry (DSC)-Part 2:Determination of glass transition temperature and glass transition step height.
This part of Iso 11357 specifies methods for the determination of the glass transition temperature and the step height related to the glass transition of amorphous and partially crystalline plastics.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1 1357-1, Plastics — Differential scanning calorimetry (DSC) — Part 1: General principles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11357-1 and the following apply.
3.1
glass transition
reversible change in an amorphous polymer or in amorphous regions of a partially crystalline polymer from (or to) a viscous or rubbery condition to (or from) a hard and relatively brittle one
3.2
glass transition temperature
Tg
characteristic value of the temperature range over which the glass transition takes place
Note 1 to entry: The assigned glass transition temperature (Tg) may vary, depending on the specific property and on the method and conditions selected to measure it.
3.3
glass transition step height
difference in specific heat capacity at Tg
Note 1 to entry: See Figure 1 and Figure 2.
Note 2 to entry: For partially crystalline polymers, the glass transition step height is proportional to the amorphous content.
4 Principle
The principle is specified in Iso 11357-1.
The change in heat flow rate as a function of temperature is measured and the glass transition
temperature and step height are determined from the curve thus obtained.
5 Apparatus and materials
The apparatus and materials are specified in ISO 11357-1.
6 Test specimens
The test specimens are specified in ISO 11357-1.
7 Test conditions and specimen conditioning
The test conditions and specimen conditioning are specified in ISO 11357-1.
8 Calibration
The calibration is specified in ISO 11357-1.
9 Procedure
9.1 Setting up the apparatus
The procedure for setting up the apparatus is specified in ISO 11357-1.
9.2 Loading the test specimen into the crucible
The procedure for loading the test specimen into the crucible is specified in ISO 11357-1.
Determine the mass of the test specimen to the nearest 0,1 mg. Unless otherwise specified in the materials standard, use a mass of between 5 mg and 20 mg. For partially crystalline materials, use a mass near the higher limit.
9.3 Insertion of crucibles
The procedure for inserting the crucibles is specified in ISO 11357-1.
9.4 Temperature scan
9.4.1 Allow 5 mm for nitrogen pre-purge prior to beginning the heating cycle.
9.4.2 Perform and record a preliminary thermal cycle at a temperature scan rate of 20 K/min, heating the cell to a temperature high enough to erase the test material’s previous thermal history.
DSC measurements on polymers are greatly affected by the thermal history and morphology of the sample and the test specimen. A first heating scan shall be performed using the test specimen as received and measurements shall be taken preferably from the second heating scan (see ISO 11357-1). In cases where the material is reactive or where it is desired to evaluate the properties of a specially pre-conditioned specimen, data may be taken during the first heating scan. This deviation from the standard procedure shall be recorded in the test report (see Clause 12).ISO 11357-2 pdf download.