Thermoplastics Dictionary

If you’re not familiar with terms used in thermoplastics, it can be overwhelming to know which one to choose for your specific application. To give you a basic understanding of common thermoplastics terms, here are some good ones to know:

Thermoplastics: A thermoplastic is a plastic polymer substance that is pliable when heated and solidifies when cooled. This heating and cooling process can be performed indefinitely without losing its characteristics.

High-Performance Plastics: These are thermoplastics that have higher requirements and characteristics than standard or engineering plastics

Specific Gravity: Refers to the weight of the part. The higher the specific gravity, the heavier the material.

Tensile Strength: The amount of force required to pull a material apart.

Flammability: In plastics, ratings are listed by thickness and time. The resin supplier generally provides the information.

Coefficient of Friction: The force needed to start a material to slide (static) and keep it moving (dynamic).

Dielectric Constant: This characteristic compares materials based on the rate at which electrical current passes through them.

Volume Resistivity: A measure to estimate how many amps go through the material with a given application of volts.

Moisture Absorption: The dimensional stability (the more water it absorbs, the more the material enlarges) and changes in properties (the more water it absorbs, the softer and less wear-resistant it becomes).

Flexural Strength: The max bending load a cross-section of the material can withstand, whether fixed at one end with a load at the other or suspended at both ends with the load in the middle.

Compressive Strength: The amount of stress required to deform a material by 10%.

Sheer Strength: The amount of stress a material can withstand when pulled/loaded in opposite directions.

Rockwell Hardness (R and M scales): The resistance to indentation a material can withstand. It is measured on an R scale for softer materials and an M scale for harder materials.

Melt Point: The temperature at which crystalline/semi-crystalline material melts (the part will often fail before it gets to this point).

Continuous Use Temperature (CUT): The maximum temperature the material can withstand in air, for 100,000 hours (11 years), with no load and still retain at least 50% of its physical properties.

For more details on these and other properties, read our Plastics Properties Understandable guide or contact us about your needs, and we’ll find a thermoplastic that meets your specifications.

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