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Transient Plane Source (TPS) Polymer Series Summary

Transient Plane Source (TPS) Polymer Series Summary

June 4, 2024

Understanding the thermal properties of materials is crucial in various industries, particularly those involving heat transfer and temperature control. Polymers, with their diverse properties and applications, are no exception. The Transient Plane Source (TPS) method offers a reliable and efficient way to evaluate the thermal properties of polymers, providing valuable insights for material selection, design, and performance optimization.

In this article, we’ll explore the TPS Polymer Series, a dedicated set of tools and procedures specifically designed for thermal property analysis of polymers. We’ll also explore this method’s key features and benefits, application process, and advantages compared to other thermal property measurement techniques.

TPS Method Overview

TPS Method Principle

The TPS (Transient Plane Source) method is a technique for measuring the thermal properties of materials. It is based on the transient plane source technique and involves using a sensor in the form of a double spiral.

TPS sensor showcasing the double spiral.

Figure 1. TPS sensor showcasing the double spiral.

To make measurements using the TPS approach, position the sensor between two samples or against the known backing insulation to obtain accurate measurements of the material’s thermal properties. During the measurement, an electrical current passes through the sensor, heating it up. At the same time, the sensor measures the rise in temperature as a function of time. This data creates a time-temperature curve, which offers valuable insight into the material’s thermal behaviour.

Single-sided TPS sensor and a two-sided TPS sensor.

Figure 2. Single-sided TPS sensor and a two-sided TPS sensor.

The time-temperature curve can be used to calculate the material’s thermal conductivity, thermal diffusivity, and specific heat capacity. These properties are important in understanding how a material conducts, transfers, and stores heat.

Overall, the TPS method is a powerful technique that allows for accurate and precise measurement of the thermal properties of materials. It is widely used in various industries and research fields to study the behaviour of materials under different thermal conditions.

Advantages of the TPS Method

The TPS method is a highly effective and reliable non-destructive technique for determining the thermal properties of various materials. Unlike other methods that may require drilling holes, cutting samples, or subjecting them to high pressures, the TPS method ensures that the integrity of the material remains intact, making it particularly suitable for testing delicate materials or samples with limited availability.

Advantages include:

  1. Non-destructive: It does not damage or alter the material tested, allowing for repeated measurements on the same sample or the preservation of the sample for further analysis.
  2. Accurate Measurement of Thermal Conductivity and Diffusivity: This method provides precise thermal conductivity and diffusivity measurements, which is crucial for understanding heat transfer through materials. These accurate measurements are essential for various scientific and engineering applications, including thermal modelling, design optimization, and performance prediction.
  3. Versatility: It can analyze various materials, including solids, pastes, powders, thin films, and even anisotropic materials. Anisotropic materials exhibit varying thermal properties in different directions, and this method can accurately determine these variations, making it a valuable tool for studying and characterizing materials with complex thermal behaviour.
  4. Reliability and Accuracy: This method has been well-established and validated. It provides reliable and accurate measurements, making it highly valuable in scientific and engineering applications where precise data is critical for research, development, quality control, and process optimization.
  5. Wide Range of Applications: This method finds applications in various industries, including research laboratories, manufacturing facilities, and other fields where understanding and optimizing the thermal properties of materials is crucial. The precise measurements obtained through using this method contribute to thermal design optimization, improved energy efficiency, and ensured various systems’ safety and reliability.

The TPS method offers a unique combination of non-destructive testing, accurate measurements, versatility, and reliability, making it a valuable tool for diverse thermal property analysis applications.

What is the TPS Polymer Series?

The TPS Polymer Series is a comprehensive suite designed to measure polymers’ thermal properties accurately. The Thermtest Measurement Platform Advanced (MP-1) measures absolute bulk and directional thermal conductivity and thermal diffusivity for solids, pastes, and powders without calibration or contact agents. It utilizes the well-established Transient Plane Source (TPS) method, which involves:

  • Sensor Placement: A specialized TPS sensor, both a heat source and a temperature sensor, is sandwiched between two halves of the polymer sample.
  • Heat Pulse Application: A short heat pulse is applied through the sensor, raising the sample’s temperature.
  • Temperature Monitoring: The sensor records the temperature rise over time, providing data for analysis.

By analyzing the temperature response, the TPS system calculates the following fundamental thermal properties of the polymer sample:

  1. Thermal Conductivity: The ability of the material to transfer heat.
  2. Thermal Diffusivity: The rate at which heat diffuses through the material.
  3. Specific Heat Capacity: The amount of heat required to raise the temperature of a unit mass of the material by one degree.

The TPS Polymer Series also includes the TPS single-sided sensor, specifically designed for situations where only one piece of sample material is available or when testing large, hard-to-handle samples. This sensor configuration allows for thermal property measurements without requiring a second half of the sample, making it ideal for:

  • Limited Sample Availability: When only a single piece of material is available, the TPS single-sided sensor enables thermal property testing without sacrificing the sample.
  • Large or Bulky Samples: Testing large or bulky samples can be challenging with traditional two-sided sensor configurations. The TPS single-sided sensor simplifies the process and allows for accurate measurements of these types of samples.

The TPS Polymer Series, including the single-sided sensor, has been successfully used to evaluate the thermal properties of various polymers, including:

The data obtained from these tests provides valuable insights into the thermal behaviour of these polymers, which can be utilized in various applications:

  1. Material Selection and Design: By understanding the thermal properties of different polymers, engineers and designers can make informed decisions when selecting materials for specific applications with defined thermal requirements.
  2. Quality Control: Thermal property measurements are crucial in quality control processes, ensuring that materials meet the necessary specifications and perform consistently.
  3. Research and Development: The TPS Polymer Series provides valuable data for researchers studying the thermal behaviour of polymers and developing new materials with optimized thermal properties.

Furthermore, the data obtained from TPS testing can be used to create thermal models that predict the behaviour of these materials under different thermal conditions. This information is crucial for optimizing product designs, ensuring efficient heat management, and predicting the performance of polymer components in various applications.

The TPS Polymer Series offers several advantages over other thermal property measurement methods:

  • Fast and Efficient: Provides rapid results, often within minutes, significantly reducing testing time.
  • Minimal Sample Preparation: Samples require minimal preparation, on occasion, only needing to be cut into even samples with smooth surfaces.
  • Wide Range of Materials: The TPS Polymer Series can be used with various polymers, including solids, pastes and powders.
  • Accurate and Reliable: The TPS method meets established international standards, ensuring precise and reliable measurements.

How is the TPS Polymer Series used to evaluate the thermal properties of polymers?

The TPS Polymer Series involves a straightforward process:

  1. Sample Preparation: Polymer samples are cut into even samples with smooth surfaces.
  2. Sensor Placement: The TPS sensor is carefully placed between two halves of the prepared sample, ensuring good thermal contact.
  3. Test Execution: The TPS system applies a short heat pulse and records the sample’s temperature response over time.
  4. Data Analysis: Specialized software analyzes the collected data to calculate the polymer sample’s thermal conductivity, thermal diffusivity, and specific heat capacity.

This process can be repeated for multiple samples of the same polymer or different polymers, allowing for comprehensive comparisons and material selection based on specific thermal property requirements.

TPS Polymer Series

Figure 3. The polymers pictured above can be effectively evaluated using the TPS Polymer Series.

Here are some examples of polymers that can be effectively evaluated using the TPS Polymer Series:

  • Polyetherimide (PEI) is a high-performance polymer known for its excellent thermal stability, mechanical strength, and electrical insulation properties.
  • Polyphenyl Sulfone (PPSU) is highly resistant to chemicals, heat, and wear, making it suitable for demanding applications in the automotive and aerospace industries.
  • Polyphenylene Sulfide (PPS) is a lightweight, dimensionally stable polymer with excellent chemical resistance and high-temperature performance.
  • Polyvinyl Chloride (PVC) is a versatile and cost-effective polymer with a wide range of applications, including construction, pipes, and electrical components.
  • Fluorinated Ethylene Propylene (FEP) is chemically inert and highly resistant to high temperatures, making it ideal for applications requiring exceptional purity and low friction.
  • Polyamide-imide (PAI): High-performance thermoplastic with outstanding thermal stability, mechanical strength, and wear resistance, suitable for demanding aerospace and automotive applications.

The TPS Polymer Series offers several advantages for polymer evaluation:

  1. Comprehensive Characterization: This provides a complete picture of the thermal properties, including conductivity, diffusivity, and specific heat capacity.
  2. Material Selection Optimization: Enables informed material selection based on specific thermal performance requirements.
  3. Quality Control and Assurance: Ensures consistent thermal properties within material batches.
  4. Process Optimization: Helps optimize processing conditions to achieve desired thermal characteristics.

Results and Applications

The TPS Polymer Series generates accurate and reliable data on the thermal properties of polymers. These results find applications in various industries, including:

  • Automotive: Optimizing thermal management in engine components, electrical systems, and interior parts.
  • Aerospace: Selecting materials for high-performance aircraft components requiring exceptional thermal stability and lightweight properties.
  • Electronics: Ensuring efficient heat dissipation in electronic devices and circuits.
  • Medical Devices: Selecting biocompatible polymers with suitable thermal properties for medical applications.

The results obtained through the TPS Polymer Series can be compared with established reference values or data from other measurement methods to validate accuracy and ensure consistency with industry standards.

Polymer Name
Bulk Thermal Conductivity

Bulk Thermal Diffusivity

General/ High Temperature

Isotropic/ Anisotropic
Reference Thermal Conductivity
Polyetherimide (Ultem) 0.22377 0.17325 High Temperature Isotropic 0.221
Polyphenyl sulfone (PPSU) 0.3097 0.2043 High Temperature Isotropic 0.302
Polyphenylene sulfide (PPS) 0.2989 0.1928 High Temperature Isotropic 0.303
Polyvinyl chloride (PVC) 0.18716 0.14783 General Isotropic 0.164
Fluorinated ethylene propylene (FEP) 0.21953 0.13689 High Temperature Isotropic 0.20 ± 0.045

Table 1. Summary table of polymers measured with corresponding bulk thermal property values and reference thermal conductivity values.

Polyamide-imide (Torlon) was measured using the TPS anisotropic module after it was discovered that the measured bulk thermal conductivity value was quite high compared to the reference. An important consideration when comparing bulk to through-thickness values, like measured values by ASTM C177, is the possibility that the materials may be anisotropic. It was then decided that the Torlon sample should be investigated for anisotropy.


Through-Thickness Thermal Conductivity

Through-Thickness Diffusivity
General/ High Temperature
Isotropic/ Anisotropic

Reference Thermal Conductivity
Polyamide-imide (Torlon) 0.55045 0.45871 High Temperature Anisotropic 0.546

Table 2. The Summary table for Torlon has corresponding through-thickness thermal properties values and reference thermal conductivity values.

The experimental results showed the accuracy of the transient plane source (TPS) method for testing low-conductivity materials such as plastic polymers. It is also a valid indication of the high precision and accuracy of the transent plane source single-sided sensor when double-sided testing is not favourable.

Conclusion and Takeaway

The Transient Plane Source Polymer Series offers a valuable tool for accurately and efficiently evaluating the thermal properties of diverse polymers. The TPS Polymer Series empowers researchers, engineers, and manufacturers to make informed material selection decisions, optimize processes, and ensure consistent thermal performance in various applications by providing comprehensive data on thermal conductivity, diffusivity, and specific heat capacity.

Understanding and characterizing the thermal properties of polymers is crucial for their successful implementation in a wide range of industries. The TPS Polymer Series provides a reliable and efficient solution, paving the way for optimized material selection and improved product performance.


  1. Writer, S. (2019, January 27). What is polyetherimide (PEI)?. Thomasnet® – Product Sourcing and Supplier Discovery Platform – Find North American Manufacturers, Suppliers and Industrial Companies.
  2. (n.d.). Polyetherimide. Science Direc. Retrieved May 1, 2024, from
  3. (n.d.). What is Fluorinatedethylenepropylene (FEP). Fluorocarbon. Retrieved May 1, 2024, from
  4. Thermtest. (n.d.). Testing Polyphenyl Sulfone (PPSU) & Polyphenylene Sulfide (PPS). Retrieved from

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