Definitions /Dictionary/Glossary - nptel

Copolymer: A resin produced by copolymerization. A process in which unlike molecules are
arranged in alternate sequence in a chain.
Core: A low-density material used between two FRP skins. Examples are end-grain balsa wood,
urethane foam, PVC foam and various honeycomb materials. The central member, usually foam
or honeycomb, has a sandwich construction to which the faces of the sandwich are attached or
bonded. It is the central member of a plywood assembly. A channel in a mold for circulation of
heat transfer media. A device on which prepreg is wound.
Coronizing: Continuous heat cleaning and weave setting.
Corrosion Resistance: A material’s ability to withstand ambient natural factors or those of a
particular artificially created atmosphere, without degrading or changing in properties. For
metals, this could be pitting or rusting; for or organic materials, it could be crazing.
Coupling Agent: Any chemical substance designed to react with both the reinforcement and
matrix phases of a composite material to form or promote a stronger bond at the interface.
Crazing: It is the cracking of gel coat or resin due to stress. It is the region of ultra-fine cracks,
which may extend in a network on or under the surface of a resin or plastic material. It may
appear as a white band. Often found in a filament-wound pressure vessel or bottle.
Creel: Glass Fiber Manufacturing - A framework used to hold forming cakes so they can be
wound or roved into roving doffs. Creels generally hold 10 to 33 forming cakes that are replaced
randomly when they run out or as doffs are roved.
Composite Fabrication: The area in which pallets of roving are placed and "threaded up"
through metal tubes or guide eyes to a chopper.
Creep: The slow movement of a plastic material with time.
Creep, Rate of: Rate of the slope of the creep-time curve at a given time. It is deflection with
time under a given static load.
Cross-linking: Chemical links between molecule chains in thermosetting resins. Styrene
monomer is a cross-linking agent in polyester resins.
C-Stage: Final stage in the reaction of certain thermosetting resins in which the material is
practically insoluble and infusible.
CTE: see Coefficient of Thermal Expansion
Cure: Cross-linking or total polymerization of a resin’s molecules that alters a material’s
properties, changing it from a liquid to a solid.