Polyisocyanates nylon

At DuPont corporation in the 1950s, as it became clear that control of nylon 6,6 production and sale would inevitably be out of the corporation s control, a polymer was synthesized, nylon 1, which was designed to allow DuPont to control another nylon-forming fiber that was of possible commercial importance. Anionic polymerization of alkyl isocyanates yields a polymer (R)NCO with stiff fiber-forming properties. However, hopes were dashed when the ceiling temperature of the polyisocyanate (nylon 1) was discovered to be near the boiling point of water. 

The pharmacological activities of other derivatives of these ring systems are examined intensively. Whereas other representatives of the above ring systems are patented as photographic sensitizers, catalysts for curing polyisocyanates, or dyes for acrylic nylon, polyester filters, and photographic material. 

Polyisocyanates are obtained by anionic polymerization using initiators such as NaCN and organo-lithiums and have the structure of 1-nylon (72).146,147 Polymerization of hexyl isocyanate with a halfmetallocene complex (73) leads to a living polymer,148... 

These reactions are discussed in this chapter. A good review of the chain structure, polymerization, and conformations of polyisocyanates should be consulted for further details on the 1-nylon-type polymers [1]. 

Recently polyisocyanates or 1-nylons have received more attention due to their chiral helical [3e] structure and their liquid crystalline properties [3f]. The older methods of polymerization involve anionic polymerization and generally the yields and molecular weights are low. 

Proteins are condensation polymers, formed by coupling amines and carboxylic acids. In proteins, the monomers (amino acids) contain both the amine and the carboxylic acid, and so they are an example of the AB type monomer shown in Figure 13.15. In fact a protein, or more specifically polyglycine, could be described as Nylon-2. Recall that Nylon-1 is the polyisocyanate structure discussed in Section 6.8.1. 

Rayon and nylon are the main fibers with which RFL dips func-tion well directly. For polyester and glass, the textiles require a special treatment, usually involving a polyisocyanate and a reactive silane respectively, to afford appropriate levels of RFL adhesion. In the glass-silane case, the mechanistic contribution is almost surely one of strong adsorption and attachment through the silane s organofunctional end with reactive R-F species. 

Ex. 7. The incorporation of PAPI, a polyisocyanate (XV), in specially compounded rubber-coating compositions has provided improved adhesion of rubber to nylon and polyester cord. " ... 

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