{"id":19500,"date":"2017-10-25T12:36:00","date_gmt":"2017-10-25T10:36:00","guid":{"rendered":"https:\/\/www.uw-elast.se\/polyuretan\/glossary-materials-science\/"},"modified":"2026-05-27T14:15:38","modified_gmt":"2026-05-27T12:15:38","slug":"glossary-materials-science","status":"publish","type":"page","link":"https:\/\/www.uw-elast.se\/en\/polyurethane\/glossary-materials-science\/","title":{"rendered":"Glossary \u2013 materials science"},"content":{"rendered":"

Adiprene<\/h3>\n
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Uniroyal’s trade name for polyurethane based on toluene diisocyanate and polyether glycols.<\/p>\n

Allophanate groups<\/h3>\n

Formed by the reaction between isocyanate groups and urethane groups.<\/p>\n

Amines<\/h3>\n

Ammonia derivatives where one or more hydrogen atoms in ammonia have been replaced by carbon-containing radicals. Amines are used, among other things, as chain extenders (curatives) and catalysts in the manufacture of polyurethanes. <\/p>\n

Aliphatics<\/h3>\n

Acyclic compounds in which the carbon atoms are bonded to each other in open, straight, or branched chains.<\/p>\n

Aliphatic isocyanates<\/h3>\n

Isocyanates based on aliphatic compounds.<\/p>\n

Aromatics<\/h3>\n

Homocyclic compounds with six carbon atoms in the ring, which are unsaturated. Aromatics can consist of several such rings. The simplest aromatic compound is benzene. <\/p>\n

Aromatic isocyanates<\/h3>\n

Isocyanates based on aromatic compounds. They are cheaper than aliphatic ones but discolor upon aging. <\/p>\n

Antioxidants<\/h3>\n

Chemical compounds that are sometimes added to prevent oxidation of, among other things, polyurethane.<\/p>\n

Elongation at break<\/h3>\n

The elongation when the specimen breaks under load.<\/p>\n

Pot life<\/h3>\n

English: “pot life”. The period during which a mixture of prepolymer and chain extender remains castable. <\/p>\n

Butanediol<\/h3>\n

Difunctional alcohol, which is used, among other things, as a chain extender in the manufacture of polyurethanes.<\/p>\n

Castomer<\/h3>\n

Baxenden Chemicals’ trade name for a series of urethane prepolymers.<\/p>\n

Hydrogen cyanide<\/h3>\n

Highly toxic. Can be formed when heating polyurethanes and isocyanates. <\/p>\n

Diisocyanates<\/h3>\n

Contains two isocyanate groups (see isocyanate). O=C=N-R-N=C=O. <\/p>\n

Tensile strength at break<\/h3>\n

The highest tensile stress a material can withstand before it breaks.<\/p>\n

Elastomers or elasts<\/h3>\n

Collective term for rubber and thermoplastic elastomers. According to ISO 1382: “polymeric material that rapidly returns to almost its original dimensions and shape upon unloading after having been subjected to severe deformation by the action of low mechanical stress.” <\/p>\n

Modulus of elasticity<\/h3>\n

E-modulus, Young’s modulus gives the relationship between stress (\u03c3) and strain (\u03b5). For practical use, steel follows Hooke’s law E=\u03c3\/\u03b5. Polymeric materials follow Hooke’s law only at very low strains. <\/p>\n

Elasticity<\/h3>\n

The ability of molecular chains to return to their original position when the load ceases.<\/p>\n

Ester groups (-COOR)-<\/h3>\n

Occur in polyester urethanes. Provide good mechanical properties but can impair hydrolysis resistance. <\/p>\n

Ether groups -O-<\/h3>\n

Provide good hydrolysis resistance in polyurethane systems, but particularly soft polyurethanes have lower mechanical properties than corresponding polyester urethanes.<\/p>\n

“Green strength”<\/h3>\n

Refers to the strength at the time of demolding.<\/p>\n

Rubber<\/h3>\n

Elast that is cross-linked or can be cross-linked so that it is practically insoluble (but can swell) in boiling solvents such as benzene and methyl ethyl ketone.<\/p>\n

Hydrophilic<\/h3>\n

Opposite of hydrophobic.<\/p>\n

Hydrophobic<\/h3>\n

Water-repellent<\/p>\n

Hydrolysis<\/h3>\n

From the Greek hydro=water, lysis=decomposition. Certain polyester urethanes are easily hydrolyzed by hot water or steam. <\/p>\n

Hydrolysis stabilizer<\/h3>\n

Carbodiimides added to polyester urethanes to delay hydrolytic degradation.<\/p>\n

Hydroxyl<\/h3>\n

Reactive group -OH<\/p>\n

Curative<\/h3>\n

Chain extender used to cure prepolymers into polyurethane. Multifunctional amines and glycols are used as curatives. <\/p>\n

Hardness<\/h3>\n

The ability of the surface to resist penetration. For polyurethanes, it is most often measured in Shore A or D. There is a certain relationship between E-modulus and hardness. <\/p>\n

Isocyanates<\/h3>\n

Reactive groups \u2013 N=C=O, which react, among other things, with hydroxyl groups (-OH) to form urethanes and with amine groups (NH2) to form urea (carbamide).<\/p>\n

Blowing agent<\/h3>\n

Used in the manufacture of cellular plastics. Blowing agents for polyurethanes include hydrofluorocarbons, hydrochlorofluorocarbons, and carbon dioxide (formed by the reaction between isocyanate and water). <\/p>\n

Catalysts<\/h3>\n

Substances that accelerate a chemical reaction without being consumed themselves. For polyurethane production, amines and tin salts are used as catalysts. <\/p>\n

Chain extender<\/h3>\n

See curative<\/p>\n

Chain length<\/h3>\n

The length of the polymer chains. Mechanical properties improve with increasing chain length. <\/p>\n

Compressibility<\/h3>\n

Rubber materials are practically considered incompressible. At high pressures, however, compressibility must be particularly considered for polyurethanes and silicone rubber. <\/p>\n

Nitrogen oxides<\/h3>\n

Hazardous to health. Formed during the combustion of polyurethanes and isocyanates. <\/p>\n

LIM<\/h3>\n

Liquid Injection Moulding.<\/p>\n

MDI<\/h3>\n

Diphenylmethane diisocyanate. An aromatic diisocyanate for the manufacture of solid and cellular polyurethanes. Not as volatile as TDI. <\/p>\n

Abrasion resistance<\/h3>\n

A material\u2019s ability to resist abrasion. Distinguish between abrasion parallel to the surface and “abrasion” caused by incoming material at a large angle of incidence. <\/p>\n

Polymer<\/h3>\n

From the Greek poly=many and mer=unit, i.e., large molecules.<\/p>\n

Polyurethane<\/h3>\n

Polymer containing urethane groups.<\/p>\n

Read more about polyurethane<\/a>.<\/p>\n

Pot life<\/h3>\n

See pot life<\/p>\n

Prepolymer<\/h3>\n

Not fully polymerized product.<\/p>\n

RIM<\/h3>\n

Reaction Injection Moulding. Often used solely for high-pressure molding. <\/p>\n

R RIM<\/h3>\n

Reinforced Reaction Injection Moulding. Reaction molding of reinforced polymers. <\/p>\n

Impact strength<\/h3>\n

A material’s ability to withstand impact stresses.<\/p>\n

Silicone oil<\/h3>\n

Often used release agent for polyurethane. Causes adhesion problems during bonding and painting. <\/p>\n

Slitan<\/h3>\n

UW-ELAST’s trade name for a series of polyether and polyester urethanes.<\/p>\n

Read more about Slitan<\/a>.<\/p>\n

Stress<\/h3>\n

Denoted by \u03c3 and is the force F divided by the area A. Often expressed in MPa.<\/p>\n

Compression set<\/h3>\n

Residual deformation after loading.<\/p>\n

Thermoelast<\/h3>\n

Elast in which the cohesive forces necessary for the material’s elastic deformation are of a physical nature and can thus be canceled by heating, whereby the material becomes plastically deformable at elevated temperatures to return to its highly elastic state upon cooling.<\/p>\n

Toluene diisocyanate<\/h3>\n

Commonly occurring aromatic diisocyanate for the manufacture of solid and cellular polyurethanes. Due to volatility and health risks, a polyurethane is often manufactured first. <\/p>\n

Trekollan<\/h3>\n

Trekollan is both a polyurethane material and a former company that is now part of UW-ELAST AB.<\/p>\n

Read more about Trekollan.<\/a><\/p>\n

Viscoelasticity<\/h3>\n

The polymer returns, with a certain time delay, to its original shape after loading. The viscoelastic part is mechanically reversible but thermodynamically irreversible. <\/p>\n

Vulkollan<\/h3>\n

Bayer’s trade name for a polymer based on naphthalene diisocyanate and polyester glycols.<\/p>\n

Read more about Vulkollan<\/a>.<\/p>\n

Urea groups -NHCONHR<\/h3>\n

Formed by the reaction between isocyanates and amine groups NH2. Also called carbamide.<\/p>\n

Urethane groups -NHCOOR<\/h3>\n

Formed by the reaction between isocyanates -N=C=O and hydroxyl groups -OH.<\/p>\n

Urethane prepolymer<\/h3>\n

Reactive viscous liquid, usually isocyanate-terminated. Provides, among other things, lower health risks than monomeric isocyanates. <\/p>\n

Vibrathane<\/h3>\n

Uniroyal’s trade name for a series of castable polyurethanes.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":4,"featured_media":0,"parent":18193,"menu_order":14,"comment_status":"closed","ping_status":"closed","template":"side-navigation.php","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-19500","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/pages\/19500","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/comments?post=19500"}],"version-history":[{"count":1,"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/pages\/19500\/revisions"}],"predecessor-version":[{"id":20909,"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/pages\/19500\/revisions\/20909"}],"up":[{"embeddable":true,"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/pages\/18193"}],"wp:attachment":[{"href":"https:\/\/www.uw-elast.se\/en\/wp-json\/wp\/v2\/media?parent=19500"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}