| acrylonitrile |
A monomer used as one of the three ingredients in ABS thermoplastic resin. |
| acrylonitrile-butadiene-styrene |
A thermoplastic polymer used as a resin for traditional composites. ABS is strong, stiff, and resistant to abrasion and impact. |
| alcohol |
An organic compound that reacts with organic acid to create unsaturated polyester. |
| butadiene |
A carbon compound used as one of the three ingredients in ABS thermoplastic resin. |
| C-glass |
A glass fiber that provides greater resistance to chemicals and is used in advanced composites. Fiberglass is generally classified as E-glass, S-glass, and C-glass. |
| composite |
A material made by combining a binding resin with small filaments of solid material. Composites have the strength of metal, the light weight of plastic, and the rigidity of ceramics. |
| creep |
A type of material deformation resulting from stress over time. Composites made from thermoplastics are vulnerable to creep. |
| cross-linking |
The development of primary bonds between polymer molecules. Thermosets are heavily cross-linked, while thermoplastics are not cross-linked or are cross-linked to a weaker degree. |
| drawing |
The process of flowing molten glass through tiny holes in a metal plate to form filaments. Drawing is part of the process for creating fiberglass. |
| E-glass |
A glass fiber with good general properties used for traditional composites. Fiberglass is generally classified as E-glass, S-glass, and C-glass. |
| epoxy |
The most common polymer used for advanced thermoset resins. Epoxies are very tough and heat-resistant. |
| fiberglass |
Reinforcement material made from extremely fine strands of glass. Traditional composites primarily use E-glass fibers. |
| fiberglass reinforced plastic |
A composite made from unsaturated polyester and fiberglass. FRPs make up a large portion of the traditional composites market. |
| filler |
An inert substance added to polymers to fill up space. Unsaturated polyester resin is low in cost because it has a high percentage of fillers. |
| freezing point |
The temperature at which a liquid resin becomes solid. The molecules in a hardened resin are frozen, or locked, in place and cannot move. |
| glass transition temperature |
The temperature at which a rigid solid becomes pliable and can be formed, shaped, or molded. The glass transition temperature is slightly below the melting point. |
| high-performance composite |
A composite made from specially formulated resins and high-performance fibers. High-performance composites are often used in applications requiring parts with high strength, stiffness, and resistance to heat. |
| inert |
Having little or no tendency to react chemically with other materials. A filler is an inert substance that is added to polymers to fill up space and reduce cost. |
| inhibitor |
A substance that slows or stops chemical activity. Inhibitors are added to polyester resin to extend its storage life. |
| liquid |
A state of matter that is cohesive and has the ability to flow. Liquid resin hardens into a solid when it cools. |
| macromolecule |
A large molecule that consists of repeating molecular units. Polymers consist of long chains of multiple macromolecules. |
| matrix |
The material that binds together the reinforcing fibers of a composite. The matrix in traditional composites is usually a polymer. |
| melting point |
The temperature at which resin becomes liquid. When a hardened resin melts to a liquid, the molecules can move about freely. |
| mer |
A basic molecular unit that consists of a collection of atoms. Polymer molecules contain thousands of repeating mers bonded in a long chain. |
| molecule |
The smallest unit into which a material can be divided without changing its properties. A molecule consists of a group of atoms held together by strong primary bonds. |
| monomer |
A small molecule that joins with other molecules to form a polymer. Acrylonitrile-butadiene-styrene is composed of monomers acrylonitrile, butadiene, and styrene. |
| multiple chains, loosely bonded |
A polymer arrangement in which cross-linking occurs to a weaker degree than in a tightly bonded multiple chain. Loose cross-linking, or no cross-linking, produces a more flexible part. |
| multiple chains, tightly bonded |
A polymer arrangement in which cross-linked molecules form strong primary bonds that connect multiple molecule chains together. Heavy cross-linking produces a stronger, more rigid part. |
| nylon |
A thermoplastic polymer used as a resin for traditional composites. There are many types of nylon, and all nylons are strong and flexible. |
| organic acid |
An organic compound that reacts with alcohol to create unsaturated polyester. |
| polyester |
The most widely used thermoset polymer in the composite industry. Fiberglass reinforced plastics are made with unsaturated polyester and fiberglass reinforcement. |
| polyethylene |
A lightweight thermoplastic polymer used to create high-performance reinforcement fibers in composites. Polyethylene is stronger than polypropylene. |
| polymer |
A long chain of very large molecules made up of many parts. Traditional composites use polymers for matrix resins. |
| polypropylene |
A thermoplastic polymer used as a resin for traditional composites. Polypropylene is economical, versatile, and very lightweight. |
| pot life |
The period of time after mixing during which a resin remains suitable for use. Polyester resin has a long pot life. |
| primary bond |
A bond that forms between atoms and that involves the exchange or sharing of electrons. Primary bonds form strong connections within molecules. |
| reinforcement |
The part of the composite that provides strength, stiffness, and the ability to carry a load. In traditional composites, E-glass fibers are the most commonly used reinforcement. |
| resin |
A substance made from either synthetic or natural polymers and used for composite matrices. In essence, a resin is a polymer that has not yet been processed into its final form. |
| secondary bond |
A bond that involves attraction between molecules but has no transfer or sharing of electrons. Secondary bonds are not as strong as primary bonds. |
| S-glass |
A glass fiber that provides greater strength and can withstand higher temperatures than E-glass. Fiberglass is generally classified as E-glass, S-glass, and C-glass. |
| single chain |
A polymer arrangement in which the molecule chains are held together by relatively weak secondary bonds. |
| single chain with branches |
A polymer arrangement in which smaller chains of mer units attach themselves to a longer polymer chain. |
| solid |
A basic non-flowing form of a substance. A solid is the room temperature form of some substances, such as plastic, or the frozen form of others, such as water. |
| strength-to-weight ratio |
The relationship between a material's strength and its weight. To find the ratio, the strength of a material is divided by its density. |
| styrene |
A monomer used as one of the three ingredients in ABS thermoplastic resin. |
| thermoplastic |
The descriptive term for a polymer in which the molecules are not cross-linked or cross-linked to a weaker degree. Thermoplastics can be melted and hardened repeatedly without changing their chemical structure. |
| thermoset |
The descriptive term for a polymer that cannot be remelted or reformed once it has cured. Thermosets have higher rigidity and better thermal stability than thermoplastics. |
| traditional composite |
A composite that uses a relatively consistent combination of resin and fiberglass reinforcement. Traditional composites are low-cost and are processed by traditional methods. |
| vinylester |
A thermoset polymer that shares common qualities with both polyester and epoxy. Vinylester is tougher and more expensive than polyester, but not as tough or expensive as epoxy. |