ASTM D1525
Determination of Vicat Softening Temperature of Plastics
Vicat Softening Temperature of Plastics: Why Is It Important?
The ASTM D1525 Vicat Softening Temperature (VST) test gauges the ability of a plastic product to retain its surface mechanical properties at high temperatures.
High-temperature mechanical properties of plastics can limit their widespread application. Some polymers are capable of withstanding temperatures of 200°C or higher, while others fail before reaching 100°C.
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Vicat Apparatus Test Procedure | ASTM D1525/ISO 306 | HDT Vicat Tester Solutions
Vicat Apparatus Test Procedure
he Vicat Softening Temperature test, also known as the Vicat Needle test, is performed by applying a point load onto the specimen and raising the temperature of that specimen at a steady rate. As soon as the point load has penetrated 1 mm into the specimen, the test ends and the temperature is recorded.
The results can then be used for development or quality control purposes, but should not be used in design calculations. The test itself is quite flexible, as there is no prescribed specimen size or shape (beyond a particular minimum footprint), and specimens can have a range of thicknesses.
ASTM D1525/ISO 306
The ASTM D1525 Vicat test has an ISO equivalent, ISO 306. This test is technically equivalent in many ways, but does not account for initial creep in the same way.
The ASTM D1525 standard also allows the use of fluidized powder as a heat-transferring medium. This system has been found satisfactory and safe for short-term heat cycles up to 500°C. It has opened the door to thermo-mechanical testing for materials (e.g., PEEK, PEI, LCP, etc.) whose standard softening temperature is greater than 300°C.
HDT Vicat Tester Solutions
The Instron® HV Series of thermo-mechanical testers is well positioned to comply with all of these standards.
Featuring intuitive on-board control (with optional automation) and easily changed testing heads, these machines are versatile and adaptable to your changing thermo-mechanical testing needs.
We can also supply the system with an oil-free heat transfer medium, for laboratories where oil-based systems are inappropriate.
Additionally, we can supply a number of specimen preparation solutions for punching and milling your specimens in preparation for testing.
To run an ASTM D1525 test, please consult the standard.
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