Research will be conducted to develop a standardized test for accurately determining the resin impregnation level in polymer matrix prepreg materials. A permeability type test will be developed which enables measurement of the open area in a prepreg material that is available for gas and volatile transport. The test will be developed into an ASTM standard so that permeability specifications can be incorporated into prepreg acceptance requirements. As a consequence of the developed test, prepreg manufacturers, composite part fabricators, and end part users can have greater confidence in the quality and reproducibility of the prepreg material from a manufacturing perspective and final part performance. Accordingly, this test will result in cost savings in manufacturing out-of-autoclave, vacuum bag only cure composite parts as well as parts made with other forms of prepreg materials.
Benefit:The test developed in this program will ultimately lead to greater quality and reproducibility of prepreg materials for use in composite part manufacturing. This test will be able to determine accurately the level of impregnation of prepreg materials, which is especially necessary for vacuum bag only cure materials. All forms of prepregs will be able to be characterized including woven fabrics and uni-tapes. It is anticipated that this test will be used by prepreg manufacturers to provide batch specification details but also used by part manufacturers for quality and process control. This test may also be used to understand the gas and volatile transport in various layups as a function of material and orientation, and therefore intra and interply permeability. Further testing of how the permeability of the prepreg or layup changes during the cure cycle could also be undertaken with this test. It is anticipated that prepreg manufacturers will also find use for this test in the design of prepreg materials through analysis of how prepreg process parameters affect the level of impregnation. Ultimately, this low cost test will become a standard that can be used universally in the composite industry for quantifying one of the most important prepreg parameters (permeability) that relates to manufacturability of fiber reinforced composites.
