Thermal conductivity tester for testing the thermal conductivity of rubber

Thermal conductivity is a key thermophysical parameter of a material, which characterizes its ability to transfer heat. Rubber, as a commonly used elastic material, is widely used in fields such as sealing, shock absorption, insulation/heat dissipation (such as tires, sealing rings, electronic equipment insulation pads, etc.). Its thermal conductivity directly affects product functionality (such as heat dissipation efficiency in high-temperature environments or insulation effect in low-temperature environments). Therefore, accurately measuring the thermal conductivity of rubber is of great significance for material selection, structural design, and performance optimization.

1、 Experimental equipment and materials

1.1 Experimental Equipment

DZDR-AS Thermal Conductivity Tester

1.2 Experimental Samples

Select three typical rubber samples:

Natural rubber (NR): Shore hardness 60, density 1.15g/cm ³;

Methyl vinyl silicone rubber (VMQ): Shore hardness 50, density 1.10g/cm ³;

Nitrile rubber (NBR, acrylonitrile content 33%): Shore hardness 70, density 1.20g/cm ³.

Sample size: diameter ≥ 40mm or length and width ≥ 40mm, with thicknesses of 2mm, 5mm, and 10mm respectively (3 sets of thickness were tested for each type of rubber to investigate the effect of thickness on the results).

1.3 Experimental steps

Sample pretreatment: Cut the rubber sample into circular thin sheets, vacuum dry at 60 ℃ for 24 hours, cool to room temperature, and place in a dryer for later use (to avoid moisture absorption affecting thermal conductivity).

Instrument calibration: Use standard acrylic sheets for instrument calibration to verify the accuracy of the testing system.

Sample clamping: Lay the sample to be tested flat on both sides of the probe, gently press to ensure close contact between the probe and the sample (apply thermal conductive silicone grease), and ensure no bubbles.

Testing process: Start the instrument, set the heating time (usually 160 seconds), and record the real-time temperature change data of the probe over time.

Data collection and storage: Export the original temperature time curve, and automatically calculate the thermal conductivity through instrument matching analysis software.

1.4 Data Processing and Result Analysis

Test results

The thermal conductivity test results (mean ± standard deviation) of three types of rubber are shown in the following table:

Measurement result analysis

Thickness influence: The deviation of test results for different thicknesses (2-10mm) of the same material is less than 5%, indicating that the TPS method is insensitive to sample thickness (lateral heat loss can be ignored when the thickness is greater than 5mm).

Repeatability: Samples from the same batch were tested 5 times, and the relative standard deviation (RSD) was less than 3%, indicating good repeatability of the transient heat source method.

Comparison with literature values: The test results are in good agreement with the literature values (relative error<5%), verifying the accuracy of the transient heat source method.