Polyamide Backbone Research Articles

Chemically modified nylons as supports for enzyme immobilization. Polyisonitrile-nylon

Four-component condensations between amine, carboxyl, isocyanide and aldehyde lead to the formation of N-substituted amides (Ugi, 1962). The present paper describes the use of such condensations for the introduction of chemically reactive groups on to the polyamide backbone of nylon. Polyisonitrile-nylon was synthesized by partial hydrolysis of nylon-6 powder, followed by resealing of the newly formed -CO(2)... NH(2) (-) pairs via a four-component condensation, by using acetaldehyde and 1,6-di-isocyanohexane. Polyisonitrile-nylon could also be converted into a diazotizable arylamino derivative, polyaminoaryl-nylon, by a four-component condensation by using a bifunctional amine, pp'-diaminodiphenylmethane, in the presence of an aldehyde and a carboxylate compound. The versatility of four-component condensations involving the isocyanide functional group of polyisonitrile-nylon allowed coupling of proteins, in an aqueous medium at neutral pH, through either their amino or carboxyl groups. Trypsin and papain were bound to polyisonitrile-nylon through their amino groups by a four-component condensation by using acetaldehyde and acetate; conversely, succinyl-(3-carboxypropionyl-)trypsin, pepsin and papain were coupled through their carboxyl groups in the presence of acetaldehyde and an amine (Tris). Diazotized polyaminoaryl-nylon could be utilized for the immobilization of papain, via the tyrosine residues of the enzyme.

Graft copolymers of phenolic novolacs on polyamide backbones

AbstractThe formation of graft copolymers of novolacs on polyamide backbones was carried out under conditions which permitted product isolation and investigation. Grafting was performed on nylons 11, 610, 66, and 6 with the use of the condensates of formaldehyde with either phenol, p‐cresol, or p‐nonyl phenol. Physical properties of the reaction products were studied, and the proof of grafting was established by means of chemical, infrared, and NMR investigations.