Preforming behaviors of carbon fiber fabrics with different contents of binder and under various process parameters

Current reported works of preforming behaviors mainly focus on the fabrics without binder and under constant process parameters. By contrast, in this work, preforming experiments and analysis were systematically conducted for typical carbon fiber fabrics to explore the influences of binder contents and process parameters on the preforming behaviors. We clearly reveal that the binder content has remarkable influence on the preforming behaviors. Specifically, the increasing binder content will significantly enlarge the initial thickness and the compression distance and time. Besides, it is demonstrated that the relaxation ability is also enhanced with the adding binder. The binder can also lower the elastic recovery, and oppositely increase the viscoelastic recovery, leading remarkable increment of permanent deformation. It is found that the binder should not be unlimitedly added, since over adding binder can not pronouncedly enhance the relaxation rate, and the content of 4 wt % is a relative optimal value for preforming process. We further reveal that the compression thickness can be reduced by lowering the compression speed. This approach will oppositely raise the preforming time. Thus, the compression speed should be carefully selected with the comprehensive consideration of both desired volume fraction and efficient. For the carbon fiber fabrics both with and without binder, the recovery thickness increases with the increasing maximum pressure. Besides, as the holding time increases, the permanent recovery ratio is also remarkably raised. The results obtained here provide systematical process reference to the preforming process of the fabrics with binder.