Adhesion to Reinforcement
The supreme advantage of epoxy is its excellent adhesion to almost any surface. Epoxy adheres tenaciously to a broad range of substrates, particularly those that are frequently used as reinforcement in composite parts and structures.
· Carbon Fiber: Carbon fiber commonly has an epoxy binder. This binder further promotes the adhesion of epoxy to the substrate and makes an epoxy the ideal resin system for the fabrication of carbon fiber composites.
· Kevlar®: Kevlar® typically does not have a binder. In this case, the superior adhesion characteristics of epoxy make it preferable to other organic polymers for the fabrication of Kevlar® composites.
· Fiber Glass: More so than carbon fiber and Kevlar® composites, fiber glass composites are susceptible to attack by water vapor. Water vapor attacks the interface between resin and reinforcement, and leads to degradation of the composite structure. In the long term, epoxy provides a barrier against water vapor that is superior to other organic polymers and can be used to fabricate more durable fiber glass composites. Fiber glass is available with a wide variety of binders. A number of these binders have been formulated to promote the adhesion of specific organic polymers to fiber glass. As such, it is important to select a grade of fiber glass with an epoxy compatible binder when using an epoxy resin system to construct fiber glass composites.
· Core Material: Where core material has been incorporated into the design of a laminate to produce a light weight composite structure, using an epoxy resin system can provide further weight savings. The superior adhesion characteristics of epoxy eliminate the need for a resin rich mat between the structural reinforcement and the core material.
Epoxy resin systems can be formulated with various curing agents, diluents, fillers and other additives to produce an almost unlimited range of properties. The tremendous versatility of epoxy makes it possible to tailor the handling and mechanical properties of an epoxy resin system to what is needed.
Epoxy resin systems exhibit little shrinkage during cure and allow for the precise reproduction of mold surfaces. The dimensional stability provided by an epoxy resin system gives rise to the fabrication of composite parts and structures with lower ingrained stress levels. As a result, finished pieces are stronger and more durable than those produced using organic polymers that exhibit higher values of shrinkage.
Properly cured epoxy resin systems have excellent chemical resistance to acids, bases and solvents. In contrast to other organic polymers, epoxy resin systems are particularly resistant to caustic substances.
No Volatile Loss
Epoxy resin systems formulated for the fabrication of structural composites are typically 100 percent solids. No byproducts, volatile or otherwise, are formed as these systems polymerize. By and large, there are no VOC issues associated with the handling of epoxy resin systems.