Effects of out-time on cure kinetics and rheological properties of out-of-autoclave and autoclave prepregs

Abstract

In aerospace applications, multiple rolls of prepreg are often used to manufacture large parts and the material is kept outside for several days during fabrication. This requirement raises issues for the fabrication of large parts where stacks of prepreg plies placed on a tool would remain at room temperature until the rest of the part is laid-up. As such, it is always a concern that the part's quality could be affected due to the material advancement in curing during outtime under ambient conditions. Although the reaction is more progressive at an elevated temperature, extended out-time at a lower temperature could also cause problems, such as a decrease in tackiness and the processability of prepreg. (Shortened)