Standard Test Method for Prepreg Resin Impregnation Level

ABSTRACT: Research will be conducted to develop a standardized test for accurately determining the resin impregnation level in prepreg materials. A permeability type test apparatus will be developed and used to quantify the level of impregnation of polymer matrix prepreg materials. This type of test equates to open volume in a prepreg material that is available for gas and volatile transport. The test will be developed so that material specifications can be incorporated into acceptance requirements for prepreg materials. This will enable greater confidence in the quality and reproducibility of the prepreg from a manufacturing perspective and final part performance. Ultimately, this test will enable cost savings in manufacturing prepreg based composites parts and especially out-of-autoclave, vacuum bag only cure composite parts. BENEFIT: The test developed in this research 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.