Tensile Testing of Reinforced Thermosetting Plastics

Intertek provides tensile testing for thermosetting plastics, including reinforced formulations.

Tensile testing ASTM D5083 scope:
The ASTM D5083 tensile test measures the force required to break a reinforced thermoset plastic specimen and the extent to which the specimen stretches or elongates to that breaking point. Tensile tests produce a stress-strain diagram, which is used to determine tensile modulus. Data can be used to specify materials, design parts to withstand application forces, and as a material quality control check. Since the physical properties of many materials can vary depending on ambient temperature, it is sometimes appropriate to test materials at temperatures that simulate the intended end use environment.

ASTM D5038 test procedure:
Specimens are placed in the grips of a Universal Test Machine at a specified grip separation and pulled until failure. For ASTM D5083 the test speed may be determined by the material specification. The default test speed is 5 mm/min (0.2 in/min), but modulus determinations may be made at 2 mm/min (0.079 in/min). An extensometer or strain gauge is used to determine elongation and tensile modulus. Depending upon the reinforcement and type, testing in more than one orientation may be necessary.

Elevated or reduced temperature test procedure:
A thermal chamber is installed on a Universal Test Machine. The chamber is designed to allow the test mounts from the base and crosshead of the Universal Test Machine to pass through the top and bottom of the chamber. Standard test fixtures are installed inside the chamber, and testing is conducted inside the controlled thermal environment the same as it would be at ambient temperature. The chamber has internal electric heaters for elevated temperatures and uses external carbon dioxide gas as a coolant for reduced temperatures.

Specimen size:
The standard specimen for ASTM D5083 has a constant rectangular cross section, 25 mm (1 in) wide and at least 250 mm (10 mm) long. Thickness can be between 2 mm (0.079 in) and 14 mm (0.55 in). Optional tabs can be bonded to the ends of the specimen to prevent gripping damage. Intertek PTL can machine the specimens from larger samples and bond tabs if requested.

Data: The following calculations can be made from tensile test results:

• Tensile Strength (MPa or PSI)
• Modulus of Elasticity (MPA or PSI)
• Elongation (%)