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These are tough elastomeric materials used in covering car steering wheels or shoe soles. The properties of a polyurethane are greatly influenced by the types of isocyanates and polyols used to make it. Long, flexible segments, contributed by the polyol, give soft, elastic polymer. High amounts of crosslinking give tough or rigid polymers. Long ...
Thermoplastic polyurethane (TPU) is any of a class of polyurethane plastics with many properties, including elasticity, transparency, and resistance to oil, grease, and abrasion. Technically, they are thermoplastic elastomers consisting of linear segmented block copolymers composed of hard and soft segments.
In the specific case of shear deformation, the elastomer besides abiding to the simplest model of rubber elasticity is also incompressible. For pure shear we relate the shear strain, to the extension ratios lambdas. Pure shear is a two-dimensional stress state making lambda equal to 1, reducing the energy strain function above to:
TPE became a commercial reality when thermoplastic polyurethane polymers became available in the 1950s. During the 1960s styrene block copolymer became available, and in the 1970s a wide range of TPEs came on the scene. The worldwide usage of TPEs (680,000 tons/year in 1990) is growing at about nine percent per year.
Polyurethane dispersion, or PUD, is understood to be a polyurethane polymer resin dispersed in water, rather than a solvent, although some cosolvent may be used.Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG (polyethylene glycol) incorporated into, or pendant from, the polymer backbone. [1]
The prepolymer, or quasi-prepolymer, can be made of an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin. [1] The resin blend may be made up of amine-terminated polymer resins, and/or amine-terminated chain extenders. The amine-terminated polymer resins do not have any intentional hydroxyl moieties. Any hydroxyls are the ...
Industrial Insulation. Rigid polyurethane foam is used in various industries to provide thermal insulation to installations and pipes. In particular, the piping for district heating systems in Europe is primarily insulated using a pre-insulated pipes sandwich assembly composed of a steel heat service pipe, an insulating layer (polyurethane foam) and a polyethylene (PE) casing, which are bonded ...
The polyurethane urea elastomer (PUU), or poly (urethane urea) elastomer, is a flexible polymeric material that is composed of linkages made out of polyurethane and polyurea compounds. Due to its hyperelastic properties, it is capable of bouncing back high-speed ballistic projectiles as if the material had “hardened” upon impact.