ASTM D7028-07(2015)

5.1 This test method is designed to determine the glass transition temperature of continuous fiber reinforced polymer composites using the DMA method. The DMA Tg value is frequently used to indicate the upper use temperature of composite materials, as well as for quality control of composite materials.

1.1 This test method covers the procedure for the determination of the dry or wet (moisture conditioned) glass transition temperature (T_g) of polymer matrix composites containing high-modulus, 20 GPa (> 3 × 10⁶ psi), fibers using a dynamic mechanical analyzer (DMA) under flexural oscillation mode, which is a specific subset of the Dynamic Mechanical Analysis (DMA) method.

1.2 The glass transition temperature is dependent upon the physical property measured, the type of measuring apparatus and the experimental parameters used. The glass transition temperature determined by this test method (referred to as “DMA Tg”) may not be the same as that reported by other measurement techniques on the same test specimen.

1.3 This test method is primarily intended for polymer matrix composites reinforced by continuous, oriented, high-modulus fibers. Other materials, such as neat resin, may require non-standard deviations from this test method to achieve meaningful results.

1.4 The values stated in SI units are standard. The values given in parentheses are non-standard mathematical conversions to common units that are provided for information only.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.