THE ROLE OF BREATHERS AND VOLATILES IN THE MANUFACTURING OF COMPOSITESTRUCTURES

Breathers have been an integral part of composite manufacturing and re pair for nearly 30 years. Yet despite their long history and almost co mmonplace usage, the function of breathers in composite manufacturing has received little attention. In this study, four different commercia l prepreg systems were consolidated in an autoclave to determine the f unction breathers play in volatile removal, part compaction, and in th e final morphology of composite parts. Breathers did not provide a gas path for the removal of volatiles during autoclaving, but were found to facilitate part compaction, In exploring the function of breathers, autoclave volatile evolution was also investigated. In the systems st udied, approximately 0.10 wt% volatiles evolved during a standard auto clave cycle. Volatiles or solvents were shown to dramatically lower th e glass transition temperature of the final composite. Ultimately, thi s work provides a scientific basis for understanding the functions of breathers in composite manufacturing.