Synthesis and Characterization of New Optically Active Poly (ethyl L-lysinamide)s and Poly (ethyl L-lysinimide)s

Ethyl L-lysine dihydrochloride was reacted with three different dianhydrides to yield the poly (ethyl L-lysinimide)s ( ); it was also reacted with two different diacyl chlorides to yield the poly (ethyl L-lysinamide)s ( ). The resulting polymers have inherent viscosities in the range of 0.15 to 0.42？dL？ . These polymers are prepared from an inexpensive starting material and are optically active, potentially ion exchangeable, semicrystalline, thermally stable, and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc, and sulfuric acid. All of the above polymers were fully characterized by FT-IR and NMR spectroscopy, elemental analysis, WAX diffraction, TGA, inherent viscosity measurement, and specific rotation. 1. Introduction Polyamides, Polyimides, and their copolymers are certainly one of the most useful classes of high-performance polymers, which have found many applications in industries as discussed by Mittal [1] and Abade [2]. Aromatic polyimides are an important class of heterocyclic polymers with remarkable heat resistance and superior mechanical and electrical properties, and also durability as discussed by Banihashemi and Abdolmaleki [3], Ghosh and Mittal [4] and Wilson et al. [5]. Various efforts have been focused on the preparation of soluble and/or thermoplastic polyimides, while still maintaining the excellent thermal and mechanical properties. Typical approaches that have been employed to improve the processability of them include the incorporation of flexible links as discussed by Tamai et al. [6], bulky pendant or cardo groups as discussed by Hsiao and Li [7] and Müller and Ringsdorf [8], kinked or asymmetric structures as discussed by Li et al. [9], and spiro skeletons as discussed by Reddy et al. [10] into the polymer chain. These modifications lower the melting temperature and lead to soluble and amorphous polymers. In general, amorphous polymers have a lower softening temperature and improved solubility with respect to their crystalline analogues. Some of the block copolymers composed of polyethers and polyamides have already been commercialized as thermoplastic elastomers as discussed by Legge et al. [11]. A number of synthetic routes for polyether-polyimide block copolymers have been known as discussed by Noshay and McGrath [12]. The synthesis and application of optically active polymers is a considerable topic, which has been paid more attention recently as discussed by Hajipour et al. [13]. Most of the natural polymers are optically active and have special chemical activities, such as catalytic properties that exist in