Polyamides properties and applications

In addition to chemical hydrolysis, hydrolysis by enzymes can operate as an alternative degradation process. It has become widely accepted that biodegradable synthetic polymers tend to be designed to mimic those structures prevailing in nature, since enzymes produced by microbial populations may not discriminate between polymers of similar structure.11 Synthetic nonpolypeptidic, chiral polyamides could mimic natural peptides or proteins, resulting in biodegradable products useful in biomedicine. 

Carbohydrate-based synthetic polymers can be prepared by polymerization of small, activated carbohydrate-derived monomers. A pioneering study in this field was the preparation and polymerization26 of methyl 2,3,4,6-telra-O-allyl-a-D-glucopyranoside (1). Under the influence of oxygen and heat, compound 1 gradually polymerizes, first to a viscous liquid and finally to a colorless, transparent resin. Similarly, acrylate and 

Diamino derivatives of carbohydrates have been employed for polycondensation reactions with carboxyl-activated aliphatic and aromatic dicar-boxylic acids. The resulting polyamides are of the AABB type (nylons-m,n analogs), and therefore, the regio- and stereoregularity in the polyamide chain is determined by the configuration of the carbohydrate precursor. When such a molecule lacks a C2 axis of symmetry, random polymerization leads to nonstereoregular polyamides. 

Anhydroalditols, which are thermostable, proved to be suitable carbohydrate precursors for polymer synthesis. Thus chiral, civ-fused bicyclic 

The polyamides 35 and 37 arc stcrcorcgular, as the precursor diamines 25 and 30 posses a C2 axis of symmetry (a symmetric distribution of the stereo-centers) and the two amino functions are topologically and stcreochemi- 

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