Prepreg: The Ultimate Composite Material

by Önder Güney, Selim Coşkun, Z. Beril Akıncı

Issue 56

Prepreg (abbreviation for pre-impregnated) is a high-tech material fabricated by the combination of a resin matrix and a fiber reinforcement material.  At this time, they are used in all aerospace programs worldwide, with Boeing 787 and Airbus A350XWB, containing more than 50% by weight of advanced composite components and other new generation high-speed vehicles such as F1 cars and racing boats and sporting tools [1]. By avoiding variable quality conditions resulting due to different laminators and non-consistent mixing processes, prepregs with real performance benefits took over a large share in the composite market.

Currently resins used in the production of prepregs are prevalently thermoset based and the most frequently used resin types are epoxy, phenolic and bismaleimide resins. Thermoset based prepregs are produced with the pre-curing of the impregnated reinforcement fibers at suitable temperatures. This action is also known as gellation where polymeric matrix transforms from A-stage to B stage. In the prepreg production the thermoset resin is in liquid form and the fiber matrix is “impregnated” within the resin. Upon removal of the excess resin, the prepreg is partially cured and the resin solidifies yet stays still tacky. At this step the prepreg is called as the “B-stage”. The full polymerization is achieved by heating this B-stage prepreg in an oven or autoclave by the end composite manufacturer. The full polymerization is achieved by heating this prepreg material in an oven or autoclave by the end composite manufacturer. This action causes the cross-linking of the polymer chains and results in the formation of a solid material, which is durable, temperature resistant, very rigid and extremely lightweight [1-2].

Login or Register PAID subscription for reading whole article.