Thermal expansion and differences can be detrimental and develop internal stresses and unusual warping in the material, which can hurt the integrity of the final part, thus making CLTE crucial for the unit economies of production and the functioning and aesthetics of the product. The linear coefficiency is measured using the following formula: It shows us the dimensional stability of a developed part under temperature variation. The coefficient of linear thermal expansion is a polymer attribute that comprises the ability of a plastic to expand under temperature elevation. The greater the heat deflection higher the chances of a faster molding process in the injection molding method.Įngaging Read – Mechanical Properties of Plastic Materials | The Definitive Guide Coefficient of Linear Thermal Expansion.Provides a value to be compared within different materials.Used in many characteristics products design and manufacturing of parts using thermoplastic components.Simply put, it can be any particular temperature at which the test bar will be warped by 0.35 mm under a given load (0.35 is a random value and has no significance). Heat deflection temperature or heat distortion temperature is a way to measure the polymer’s resistance or withstanding capacity towards distortion at a given temperature. The above table shows that the continuous service temperatures for all the polymers are more than the Tg value. Over the temperature limit, the mechanical and electrical properties of the material will start degrading over a period of time. Continues Service TempratureĬontinuous service temperature is the temperature at which a material can perform assuredly in a long-term application. Interesting Read – How is Plastic Made? A Simple and Detailed Explanation. The crystalline molecules have a melting point, and the amorphous molecules have a glass transition temperature. There are polymers with a partially crystalline structure, with the crystalline regions spread within the amorphous material. however, they have scattered around even though they are not solid-state. Their molecular structure comprises unsynchronized molecular chains not arranged in ordered crystals. These polymers soften upon heating over a wide range of temperatures. Amorphous PolymersĪmorphous polymers are also known for not having a melting point but a glass transition temperature. High crystallinity also means that less light will pass through these materials.Ĭrystallinity will provide benefits like chemical resistance, strength, stability, and stiffness. More crystallinity means more strength and less flexibility for the materials. These polymers have regular chain structures and are more likely to form crystalline regions. It includes materials like PEEK, PPS, PFA, etc. Crystalline materials have a highly ordered and defined molecular structure. Their melting point is a temperature where is ordered molecular structure becomes disordered liquid. Crystalline materials don’t have a specific glass transition temperature.
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