Maximum stress sustained by a composite specimen before it fails in a tension test.
A unit of linear density. Mass in grams per 1000 metres of yarn, fibre or other strand. Also known as Bundle Tex or Strand Tex.
Ability to transfer heat.
A polymer based material that will repeatedly soften when heated and harden when cooled.
A polymer based material that will undergo or has undergone a chemical cross linking reaction by the action of heat, catalyst, ultraviolet light etc, leading to a solid state which cannot be reversed.
Materials which are gel-like at rest but flow easily when agitated. These materials have a high static shear strength and a low dynamic shear strength.
A measurement of thixotropic nature using a Brookfield viscometer, calculated as the low speed viscosity divided by the high speed viscosity.
An ultra-thin non-woven mat of reinforcing fibres. The tissue supports a resin rich layer in a laminate. It is also called veil.
The mould, either open or closed, in or upon which composite materials re-formed.
An untwisted bundle of continuous filaments. Tow is usually written in the form of a number followed by K e.g. 16K, where K indicates multiplication by 1000 (16K tow has 16,000 filaments).
A fibre, tow or yarn, usually a contrasting colour added to a fabric to verify fibre alignment.
Wrinkling of gelcoat caused by styrene attack of under-cured gelcoat when the backing resin is applied.
Negative or reverse draft on the mould. Split moulds are necessary to shape parts that are undercut.
Fabric, tape or laminate where the fibres are all oriented in the same direction (straight, parallel and continuous).
VACUUM ASSISTED RESIN TRANSFER MOULDING (VARTM)
A composite fabrication process using infusion. A vacuum draws resin into a one-sided (open) mould which has a rigid or flexible cover placed over the top to form a vacuum tight seal.
VACUUM BAG MOULDING
A composite fabrication process where the reinforcement and resin are applied by hand lay-up or spray-up and then a flexible bag is sealed over the part and a vacuum drawn whilst the part cures.
An ultra-thin non-woven mat of reinforcing fibres. The veil supports a resin rich layer in a laminate. Also called tissue.
VINYL ESTER RESIN
A type of thermosetting resin that is usually derived from an epoxide, glycol and unsaturated acid, with styrene monomer added.
The tendency of a fluid to resist flow.
A pocket of entrapped gas that has been cured into a laminate.
VOLATILE ORGANIC COMPOUNDS (VOCS)
Carbon containing chemical compounds (e.g. solvents and styrene) that evaporate readily at ambient temperatures. Regulations often limit exposure to VOCs so that low VOC content is preferable.