Priming compositions binders

Problems associated with the use of prepreg for composite fabrication included a high bulk factor and difficulties in obtaining an optimum resin pre-cure to ensure correct consolidation. One approach was to use pressure assisted resin injection, where a fiber preform contained in a mold was evacuated and a fairly mobile resin pumped in under pressure [64]. To help maintain the accurate alignment of the fiber in the perform, it was held in place by a resin binder made of about 4% polysulfone applied as a solution in methylene chloride, drying to remove solvent and then followed by a short treatment at 320° C to fuse the polysulfone onto the fiber. Next, a laminate of primed sheets was prepared, which was about 2.5 times the bulk volume of the finished composite (i.e., when compressed at 0.65 f/). Two techniques were used to consolidate a preform. 

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