GB/T 19466.8-2025Plastics - Differential scanning calorimetry (DSC) method - Part 8: Determination of thermal conductivity (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is Part 8 of GB/T 19466, "Differential Scanning Calorimetry (DSC) Method for Plastics". GB/T 19466 has published the following...

part.

---Part 1: General Rules;

---Part 2: Determination of glass transition temperature and step height;

---Part 3: Determination of melting and crystallization temperatures and enthalpy;

---Part 4: Determination of specific heat capacity;

---Part 5: Determination of temperature, time, enthalpy of reaction, and conversion rate for characteristic reaction curves;

---Part 6: Determination of oxidation induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT);

---Part 7: Determination of Crystallization Kinetics;

---Part 8: Determination of thermal conductivity.

This document is modified to adopt ISO 11357-8:2021 "Plastics - Differential scanning calorimetry (DSC) - Part 8: Determination of thermal conductivity".

This document has undergone the following structural adjustments compared to ISO 11357-7:2022.

---The word order has been changed (see Chapter 4).

The technical differences between this document and ISO 11357-8:2021, and the reasons therefor, are as follows.

---ISO 427 has been replaced by the normatively referenced GB/T 2035 (see Chapter 3), and ISO 11357-1 has been replaced by GB/T 19466.1.

(See Chapters 3, 5.1, 8, 9.3.1, and 9.4) to adapt to my country's technological conditions and increase operability;

---Change the first paragraph of Chapter 4 of ISO 11357-8:2021 to a note (see Chapter 4) to conform to GB/T 1.2-2020.

in principle;

---The phrase "according to ISO/FEPA standards" has been removed and replaced with "according to GB/T 9258.1" (see 6.1) to better suit my country's technical requirements.

The components are designed to be easy for operators to use.

---ISO 6344-1 (see 6.1) has been replaced with the normatively referenced GB/T 9258.1 to adapt to my country's technical conditions and increase operability.

Actual nature;

---ISO 291 has been replaced with the normatively referenced GB/T 2918 (see Chapter 7) to adapt to my country's technical conditions and increase operability.

Actual nature;

---Added the conditional adjustment under the conditions of "temperature (23±2)°C and relative humidity (50±10)%" (see Chapter 7), and added...

Operability;

---The requirements for the use and inspection of heat-contact materials have been changed (see 9.2) to better align with actual testing requirements and increase operability.

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed by the China Petroleum and Chemical Industry Federation.

This document is under the jurisdiction of the National Technical Committee on Plastics Standardization (SAC/TC15).

Introduction

The advantage of using differential scanning calorimetry (DSC) to determine the thermal conductivity of plastics is that specific heat capacity and thermal diffusivity can be obtained using the same instrument.

The efficiency can be determined by dividing the thermal conductivity by the density and specific heat capacity. Furthermore, the differential scanning calorimeter (DSC) is used in the testing machine...

It is used in construction and laboratory settings, so the thermal conductivity can be measured without the need to purchase additional instruments.

GB/T 19466 "Differential Scanning Calorimetry (DSC) Method for Plastics" is a standard that uses differential scanning calorimetry (DSC) to measure the properties of thermoplastic and thermosetting materials.

Standard methods for thermal analysis of polymers, including molding materials and composites, in the field of plastics. These methods include the use of differential scanning calorimetry.

The general rules and methods for various thermodynamic and kinetic determinations of polymers are proposed to consist of eight parts.

---Part 1: General Rules. The purpose is to establish a method for determining the composition of plastics, including molding materials and composites, using differential scanning calorimetry (DSC).

The general principles and relevant rules governing the thermodynamics and kinetics of polymers such as materials.

---Part 2: Determination of Glass Transition Temperature and Step Height. The purpose is to provide a basis for the determination of glass transition temperature and step height.

Establish comparable methods.

---Part 3: Determination of Melting and Crystallization Temperatures and Enthalpy. The purpose is to determine the melting and crystallization temperatures of crystalline and semi-crystalline polymers.

Establish comparable methods for the determination of enthalpy.

---Part 4: Determination of specific heat capacity. The aim is to establish an operable, traceable, and verifiable procedure for determining the specific heat capacity of plastics.

---Part 5: Characteristic Reaction Curves - Determination of Temperature, Time, Enthalpy, and Conversion Rate. The purpose is to provide a basis for determining the reaction rate of solid or liquid monomers.

Establish comparable methods for determining the temperature and time, enthalpy of reaction, and conversion rate of the prepolymer and polymer reaction.

---Part 6: Determination of Oxidation Induction Time (Isothermal OIT) and Oxidation Induction Temperature (Dynamic OIT). The aim is to provide a basis for determining the oxidation induction time (OIT) and oxidation induction temperature (Dynamic OIT) of polymers.

Establish comparable methods for determining the oxidation induction time and oxidation induction temperature of materials.

---Part 7: Determination of Crystallization Kinetics. The aim is to establish comparable methods for determining polymer crystallization kinetics.

---Part 8: Determination of Thermal Conductivity. The aim is to establish comparable methods for determining the thermal conductivity of plastics.

Differential Scanning Calorimetry (DSC) for Plastics Part 8: Determination of Thermal Conductivity

1 Scope

This document describes the determination of unfilled plastics, filled plastics, fiber-reinforced plastics, and composites using differential scanning calorimetry (DSC).

Methods for measuring thermal conductivity.

This document applies to materials with a thermal conductivity not exceeding 1 W·m-1·K-1.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 2035 Plastics Terminology (GB/T 2035-2024, ISO 472:2013, NEQ) GB/T 2918 Standard environment for conditioning and testing of plastic specimens (GB/T 2918-2018, ISO 291:2008, MOD) GB/T 9258.1 Abrasive grain size analysis for coated abrasives – Part 1: Grain size composition (GB/T 9258.1-2000) ISO 6344-1:1998, IDT GB/T 19466.1 Differential Scanning Calorimetry (DSC) for Plastics – Part 1: General Rules (GB/T 19466.1-2025) ISO 11357-1:2023, MOD)

3 Terms and Definitions

The terms and definitions defined in GB/T 2035 and GB/T 19466.1 apply to this document.

4 Principles

Place the empty crucible at the reference end, place the sample directly on the sensor at the sample end, and then place the crucible containing the substance with a known melting temperature on the sensor.

Placed on top of the sample (see Figure 1). During heating, a temperature gradient will be generated in the sample. The temperature at the top of the sample is close to the melting temperature of the molten material.

The temperature remains constant at Tm, while the temperature at the bottom of the sample is consistent with the temperature of the sensor at the end of the sample.

Thermal conductivity is measured over a relatively small temperature range at temperatures slightly above the melting point of the molten material. Within this temperature range, the properties of the molten material are determined.

The melting peak slope of the substance (see 9.4, Figure 2), the difference in heat flow rate between the sample end and the reference end measured by DSC instrument, and the top and bottom of the sample.

The thermal conductivity of the sample is calculated by taking the temperature difference (Tm-Tp) between the two.

Note. According to the procedures proposed in references [1] and [2], the thermal conductivity of the sample needs to be determined by changing the conventional placement of the sample on the sample holder. More details...

For background, results derivation and detailed information on measurement performance, see references [3] and [4].