Cross-linking in these compounds can result in the formation of an allophane group. They are used in
Cross-linking in these compounds can result in the formation of an allophane group. They are used in Numa and Vyrene as well as lightweight cores for aircraft wings, and common raw materials in their preparation include MDI and TDI. They are formed when those di-isocyanates react with diols, since their repeating units are synthesized by an alcohol group adding across a carbon-nitrogen double bond resulting in a carbonyl single bonded to an NH. FTP, name ►these polymers used in Lycra and other spandex fibers, as well as flexible and rigid foams.
Cross-linking in these compounds can result in the formation of an allophane group.
polyurethanes 