Prepreg material preparation

Helmet material preparation process (a) Prepreg roll, (b) Petal marking process, (c) Manual cutting, (d) Dome formation. 

Grafting of maleimide copolymers on conjugated diolefin elastomers has been discovered as a route to new molding resins with improved physical properties.Low-molecular-weight polybutadiene, with substantial 1,2-microstructure, have also been heated with bismaleimides and peroxides to obtain grafted prepreg materials. Composites prepared from these... 

Another method that has great potential for the preparation of advanced prepregs and has been explored extensively requites fine powders. The reinforcing fibers are coated with fine particles of the resin and, when heated, the resin flows over the fiber. This method requites finely divided particles either in aqueous solution, in an inert volatile solvent, or as high dielectric material that can be charged and coated by electrostatic attraction to the fiber. Synthetic methods that make fine particles, similar to that described for PEEK (23), are needed. 

The fabrication of components from advanced composite materials also requires suitable tooling to shape and conform the prepreg during lay-up and epoxy have a role to play in this operation as well. Whilst less durable than conventional tooling constructed from steel or aluminum, tooling prepared from carbon fiber reinforced epoxy resins offers lightweight and, most importantly, a good match with the... 

The neat resin was prepared by casting. The epojgr material was first subjected to degasification at 85°C inside a vacuum oven. The softened liquid v as then poured into a preheated mold. The curing schedule was 121°C for 2 h and 177°C for 2.5 h, followed by a slow cooling at ca. 0.5°C per m n. to room temperature. Symmetrically reinforced (i45°) g Thomel 500/Fiberite 954 laminates were fabricated from prepreg tapes obtained from Piberite Corporation. The details on specimen fabrication are described elsewhere (8). 

Figure L.I Horizontal treater for preparing prepreg for laminates. (Ref Harper, C.A., Laminates and Reinforced Plastic Materials and Processes , Handbook of Plastics, Elastomers, and Composites, 3 ed., C.A. Harper, ed., McGraw-HiU, New York, 1996)...

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