Long Out-time, Out-of-Autoclave Cure Composites

As the size of composite parts exceed that of even the largest autoclaves, new out-of-autoclave processes and materials are necessary to achieve the same level of performance as autoclave cured composites. Unfortunately, the quality of composites manufactured with current out-of-autoclave prepreg systems is limited by their short shelf-life at ambient conditions. The resin advancement, due to long lay-up times, commonly causes variations in fiber volume and higher void content in the cured structures. Also, current out-of-autoclave prepreg systems do not provide the same level of performance, especially damage tolerance, as many current autoclave cured prepreg systems. It is the objective of this work to develop a matrix and prepreg system for out-of-autoclave processing that has a year out-time at ambient conditions while also providing an excellent balance of mechanical properties and damage tolerance. As an additional functionality, the out-of-autoclave prepreg system will be developed to have inherent skin-core self-adhesive properties so that film adhesives are not required for designs with honeycomb cores. It is expected that the TRL will be 4 at the end of this Phase I program.