Glossary of terms used in the polyurethanes business

Courtesy of Smithers-Rapra & Cromar Solutions Ltd, UK

 

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Cast, casting The filling of essentially open moulds with liquid mixtures of polyurethane reactants or liquid monomers and allowing them to polymerise in situ. A CPU is a cast polyurethane.

Catalyst A substance which accelerates the reactions of chemicals without itself being consumed.

Cell structure Open cells - interconnecting cells in a foam. Closed cells - cells enclosed by continuous membranes and struts. Cell opening - the breaking of intercellular membranes. This can occur naturally during foam rise, or later by foam crushing. Cell count - the number of cells per linear centimetre.

Chain extenders Substances which lengthen the main chain of a polymer molecule by causing end-to-end attachments. Chain extenders usually have a functionality of 2.

Component When applied to polyurethane manufacture, a component is one of at least two reactive materials which are mixed together to form a polymer.

Condensation polymerisation A polymerisation reaction in which two or more molecules combine with the production of by-products, such as water.

Covalent A chemical bond between two separate atoms in a molecule involving the sharing of electrons by two atomic nuclei.

Critical velocity The rate of flow of a liquid at which smooth laminar flow changes to turbulent flow.

Crosslinking Formation of bridges between different polymer chains
  • Chemically, through reaction
  • Physically, by e.g hydrogen bonding, covalent linkages

Crystallinity State of repeated, and ordered, molecular organisation.

Cure Refers to the completeness of chemical reaction processes.