Elastomer urethane

Foamed urethane elastomers are also called microcellular elastomers. The densities are in the range of about 20 to 60 pcf (320 to 960 kg/m. Integral-skin foams having a density of ca. 700 to 1,000 kg/m are sometimes referred to as microcellular elastomers. 

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A series of compounded flame retardants, based on finely divided insoluble ammonium polyphosphate together with char-forming nitrogenous resins, has been developed for thermoplastics (52—58). These compounds are particularly useful as iatumescent flame-retardant additives for polyolefins, ethylene—vinyl acetate, and urethane elastomers (qv). The char-forming resin can be, for example, an ethyleneurea—formaldehyde condensation polymer, a hydroxyethylisocyanurate, or a piperazine—triazine resin. 

Uretha.nes. Urethane elastomers are prepared by the reaction of an isocyanate molecule with a high molecular weight ester or ether molecule. The result is either an elastomeric mbber form or a Hquid prepolymer that can be vulcanised with an amine or a hydroxyl molecule (see Urethane POLYAffiRS). 

Uses. Approximately 70% of the U.S. production is used to make poly(tetramethylene ether glycol) [25190-06-1] (PTMEG), also known as poly-THE, which is used in the production of urethane elastomers, polyurethane fibers (ether-based spandex), and copolyester—ether elastomers. PTMEG is also the fastest growing use (see PoLYETPiERS, TETRAHYDROFURAn). The remaining production is used as a solvent for the manufacture of poly(vinyl chloride) cements and coating, precision magnetic tape, a reaction solvent in the production of pharmaceuticals, and other miscellaneous uses. 

FRISCH, K. c.. Recent Developments in Urethane Elastomers and Reaction Injection Moulded (RIM) Elastomers, Rubber Chem. Technol., 53, 126 (1980)... 

Flexural modulus is the force required to deform a material in the elastic bending region. It is essentially a way to characterize stiffness. Urethane elastomers and rigid foams are usually tested in flexural mode via three-point bending and tite flexural (or flex ) modulus is obtained from the initial, linear portion of the resultant stress-strain curve. 

There are several ways to measure a material s resistance to tearing. In these tests, the applied force is not distributed over the entire specimen but is concentrated on a slit or notch and the tear strengtii is reported as the force required to propagate a tear from this point. For urethane elastomers and foams, the most... 

Unsaturated polyester resins (UPRs) Uralkyd resins, 202 Urea-methylol reaction, 410 Urethane alkyds, 241 Urethane coatings, 202 Urethane elastomers, implanted, 207 Urethane foams, tests for, 244 Urethane gels, 205 Urethane-grade ATPEs, 223 Urethane-grade polyol types, 212 Urethane-grade raw materials, 246 Urethane hydrogel, preparation of, 250-251... 

Bmin P, Veensda GJ, Nijenhuis AJ, and Pennings AJ. Design and synthesis of biodegradable poly(ester-urethane) elastomer networks composed of non toxic building blocks. Makromol Chem Rapid Common, 1988, 9, 589. 

Leis, D.G., Reinforced RIM Urethane Elastomer—A New Material of the Automotive Industry, 34th SPI Reinf. Plast./Compos. Conf, p. 11 A, 1979. 

Balas, A., Palka, G., Foks, J., and Janik, H., Properties of cast urethane elastomers prepared from poly( e-caprolactone)s,... 

Also, polymer additives in medical plastics have been analysed by means of GC-MS [293]. 4,4 -Methyl-enebis(2-chloroaniline) (MBOAC), used in the polymer industry to cure urethane elastomers and epoxy resins, has been analysed in body fluids by means of GC-MS [294]. GC-MS has also been used to examine extracted PP/Triclosan (sanitiser) [243]. 

Castor oil-urethane elastomers were prepared by reacting 2,4 tolylene diisocyanante, TDI, 80/20 2,4/2,6 TDI, or hexamethylene diisocyanate (HDI) with castor oil. The last reaction was rather slow and thus dibutyltin dilaurate, 0.001 gm per gm of HDI, was used as a catalyst. Since TDI hydrolyses significantly in the presence of trace amounts of water, DB grade castor oil from the Baker Castor Oil Company (NL Industries) was employed. 

In order to synthesize the IPN, the urethane elastomer was swelled with styrene containing 0.4% benzoin as initiator and 1% divinyl benzene (DVB) as crosslinker. Polymerization of the styrene was carried out by ultraviolet radiation at room temperature for 24 hours. 

Cellasto Microcellular urethane elastomer North American Urethane... 

Observations Although poly(urethane) elastomers have been used extensively in... 

The diphenylmethane 4.4 diisocyanale is used in the manufacture of solid urethane elastomers (primarily lor heavy-duty tires) and chemically resistant coatings. 

Fig. 10. Compression stress-strain properties of various elastomeric syntactic foams129> (l)urethane elastomer binder and glass microspheres y = 640 kg/m3, void fraction 0.321 (2) polysulfide elastomer binder and phenolic microspheres y = 1500 kg/m3, void fraction 0.133 (3) silicone elastomer binder and glass microspheres y = 610 kg/m3, void fraction 0.407...

Magnus, G., R.A. Dunleavy, and F.E. Critchfield. "Stability of Urethane Elastomers in Water, Dry Air and Moist Environments." Rubber Chemistry and Technology (1967) 1328-1337. 

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