Urethane network polymers

Urethane network polymers are also formed by trimerization of part of the isocyanate groups. This approach is used in the formation of rigid polyurethane-modified isocyanurate (PUIR) foams (3). 

Wiggins,J.S. and Storey, R. (1992) Synthesis and characterization of l.-lysine based poly(ester-urethane) networks. Polym. Preprints., 32, 516-517. 

Modification of poly(carbodiimide) foams with polyols afford hybride foams containing urethane sections. However, the thermal stabilities of the poly (urethane carbodiimide) foams are lower. Using isocyanate trimerization catalysts, such as l,3,5-tris(3-dimethylaminopropyl)hexahydro-s-triazine, in combination with the phospholene oxide catalyst gives poly(isocyanurate carbodiimide) foams with improved high temperature properties. The cellular poly(carbodiimide) foams derived from PMDI incorporate six-membered ring structures in their network polymer structure. ... 

Coatings from Urethane Interpenetrating Polymer Networks (IPNs)... 

When the process involves two competitive reactions, some people prrfer to call those modified polymers interpenetrated polymer networks (IPNs) [5]. The formation of a polyether-urethane network in a loosely crosslinked poly(methyl methacrylate) matrix to increase its toughness can serve as one of the examples. From a general point of view, the analysis of the reaction-induced phase separation is the same (perhaps more complex) for IPNs than for rubber-modified epoxies or for high-impact polystyrene. 

Storey RF, Wiggins JS, Puckett AD. Hydrolyzable poly(ester-urethane) networks from L-lysine diisocyanate and D,L-lactide/e-caprolactone homo- and copolyester triols. JPolym Sci, Part A Polym Chem 1994 32(12) 2345-2363. 

Cardiothane Kontrol, Inc. A silicone-urethane interpenetrating polymer network. Limited availability. 

Yu. S. Lipatov, L. V. Karabanova, T. S. Khramova, and L. M. Sergeeva, Study of Physicochemical Properties of Interpenetrating Polyurethane and Poly(urethane acrylate) Polymer Networks, Vysokomol. Soedin. Ser. A 20(1), 46 (1978). Thermodynamics and Swelling of IPNs and PU-based IPNs. 

M. Matsuo, T. K. Kwei, D. Klempner, and H. L. Frisch, Structure Property Relations in Polyacrylate-Poly(urethane-urea) Interpenetrating Polymer Networks, Polym. Eng. Sci. 10(6), 327 (1970). Polyacrylate/polyurethane urea lENs. Polyurethane/ureapolyacrylate lENs. Morphology via electron microscopy. 

L. H. Sperling, J. A. Manson, G. M. Yenwo, A. Conde, and N. Devia, Castor Oil Based Interpenetrating Polymer Networks, Polym. Prepr. Am. Chem. Soc. Div. Polym. Chem. 16(2), 604 (1975). Castor oil-urethane/PS IPNs. Glass transitions and morphology. 

Wilson, T.S., Bearinger, J.P., Herherg, J.L., Marion, J.E., Wright, W.J., Evans, C.L., Maitland, D.J., 2007. Shape memory polymers based on uniform aliphatic urethane networks. Journal of Applied Polymer Science 106,540-551. 

Richter, E.B. and Macosko, C.W. (1980) Viscosity changes during isothermal and adiabatic urethane network polymerization. Polym. Eng. Sci., 20, 921-924. 

Ahir, S. V., Tajbakhsh, A. R.,Terentjev, E. M. (2006), Self-assembled shape-memory fibers of tri-block liquid-crystal polymers,. Advanced Functional Materials, 16,556-60. Alteheld, A., Feng, Y. K., Kelch, S., Lendlein, A. (2005), Biodegradable, amorphous copolyester-urethane networks having shape-memory properties, Angewandte Chemie - International Edition, 44,1188-92. 

Network polymers, e.g., silicones, epoxies, and urethane foams... 

Siloxane-based electrolytes appear to be an excellent choice due to the low glass transition temperature of many siloxane polymers. The si loxane-based electrolyte described here consists of a methyls loxane backbone with pendent polyether sidechains and crosslinks. Other siloxane electrolytes which have been studied Include a copolymer liquid electrolyte comprised of dimethylsiloxane and ethylene oxide repeat units, and a urethane network of poly(dlmethyIsiloxane grafted ethylene oxide). Initial reports have also appeared on siloxane-... 

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