Federal Aviation Administration.
The standard, D7028, Test Method for Glass Transition Temperature (DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA), is under the jurisdiction of Subcommittee D30.04 on Lamina and Laminate Test Methods, part of ASTM Committee D30 on Composite Materials.
According to Michael Stuart, D30 member and senior technical service engineer, Cytec Engineered Materials Inc., the new test method provides instructions on how to measure the glass transition temperature of continuous fiber reinforced composites to determine whether the material falls within FAA guidelines. The DMA Tg value is frequently used to indicate the upper use temperature of composite materials, as well as for quality control of these materials.
Stuart says that ASTM D7028 will be used for research, material characterization and screening and other programs. In addition, the standard will allow for greater and more effective use of glass transition temperature testing. “Many different instruments and analysis methods, which can produce profoundly different values, are used for glass transition temperature measurements,” says Stuart. “A standard was needed to define the test procedure and protocol for Tg measurements to facilitate broader usage within the composites industry.”
Stuart says that the subcommittee welcomes new members to address future revisions of D7028 and related standards, as well as to work on the development of proposed new standards.