Quote from Guest on July 21, 2025, 11:21 am

Plastics are widely used across industries due to their lightweight nature, corrosion resistance, and ease of fabrication. However, their thermal conductivity coefficients play a crucial role in determining their suitability for specific applications, especially in thermal insulation, electronics, and high-temperature environments. Alfa Chemistry provides typical values of thermal conductivity for some common plastics for reference.

Overview of Thermal Conductivity of Plastics

Thermal conductivity (k) is the measure of a material's ability to conduct heat. For plastics, this value is typically low compared to metals, making them excellent thermal insulators. The thermal conductivity of most common plastics ranges between 0.1 to 0.5 W/m·K, although specialty-engineered polymers can achieve higher values.

The following table summarizes the thermal conductivity coefficients of common plastics^[1]:

Plastic	Thermal Conductivity
Polypropylene (PP)	0.11 W/m·K
Polystyrene (PS)	0.14 W/m·K
Polymethyl methacrylate (PMMA)	0.21 W/m·K
Polycarbonate (PC)	0.19-0.22 W/m·K
Polyethylene terephthalate (PET)	0.15 W/m·K
Polybutylene terephthalate (PBT)	0.29 W/m·K
Polyoxymethylene (POM)	0.29 W/m·K
Polyimide (PI)	0.11 W/m·K
Polytetrafluoroethylene (PTFE)	0.25 W/m·K
Polyamide (Nylon)	0.26 W/m·K
Polyethylene, low density (PEL)	0.33 W/m·K
Polyethylene, high density (PEH)	0.44 W/m·K
Polyvinyl chloride (PVC)	0.19 W/m·K
Acrylic	0.2 W/m·K
Epoxy	0.19 W/m·K
Epoxy glass fibre	0.23 W/m·K
Polydimethyl siloxane (PDMS, silicone)	0.25 W/m·K
Polyphenylene sulfide (PPS)	0.3 W/m·K

Factors Influencing Thermal Conductivity

• Molecular Structure

Plastics with highly ordered crystalline structures, such as polyethylene terephthalate (PET), exhibit higher thermal conductivities due to efficient heat transfer along ordered chains. Conversely, amorphous plastics like polystyrene have lower conductivity.

• Filler Materials

The incorporation of thermally conductive fillers such as graphite, boron nitride, or metal oxides can dramatically enhance a polymer's thermal conductivity. For instance, high-density polyethylene (HDPE) filled with aluminum particles can achieve values exceeding 1 W/m·K.

• Processing Conditions

The thermal history and processing parameters, such as cooling rate and annealing, influence crystallinity and void content, which directly affect heat conduction.

• Operating Environment

Factors such as temperature and humidity can alter thermal conductivity. For example, elevated temperatures can increase molecular mobility, enhancing conductivity slightly in some cases.

Applications of Plastics Based on Thermal Conductivity

Thermal Insulation

Low-conductivity plastics like expanded polystyrene (EPS) and polyurethane foam are staples in the construction and refrigeration industries. Their ability to trap air within their structure minimizes heat transfer.

Electronics and Heat Management

For applications requiring thermal dissipation, such as housings for LED lighting or battery casings, specialty thermally conductive plastics are used. Polycarbonate with added fillers is common in these scenarios.

High-Temperature Components

Polymers like PI and PEEK (polyether ether ketone) are utilized in high-performance applications due to their stability and moderate thermal conductivity, which balance insulation and heat resistance.

Understanding the thermal conductivity coefficients of plastics is critical for selecting materials that meet performance and cost requirements. With ongoing advancements in filler technologies and polymer chemistry, plastics are poised to address emerging challenges in thermal management across industries. These properties make plastics not only versatile but also indispensable in modern engineering.