Polyisophthalamides with heteroaromatic pendent rings: Synthesis, physical properties, and water uptake

Abstract

A set of novel aromatic polyamides containing pyridine pendent groups was prepared from aromatic diamines and new monomers that are 5-substituted derivatives of isophthalic acid bearing nicotinamide, isonicotinamide, or picolinamide groups. The polymers were obtained in high yield and high molecular weight by the phosphorylation method of polycondensation. They were characterized by spectroscopic and chromatographic methods and several of their properties were investigated. All of the polymers were soluble in polar aprotic solvents and gave films of good mechanical properties. Glass transition temperatures were higher than that of the reference polymer, poly(m-phenyleneisophthalamide) (IP-MPD), while the thermal resistance, defined by the initial decomposition temperature observed by thermogravimetry, was in the range 370-420 8C, lower by 30-70 8C than that of IP-MPD. The presence of a pendent pyridine group and an additional amide side group per repeat unit made the polymers essentially amorphous and greatly improved their abilities to absorb water in comparison with nonsubstituted polyamides. Water uptake values up to 15% were observed at 65% relative humidity. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5300-5311, 2005

Polyamides – Still Strong After Seventy Years

“…Two studies of interest concern the incorporation of pendant groups onto the aramid chain. Ferreiro et al [125] added pyridyl rings to the isophthalamide component simply in order to make the polymer more tractable and easy to work with in the liquid phase, while trying to minimize impact on final properties. Chaudhuri et al [126] tried various organic and other substituents on MPD in order to enhance resistance to burning.…”

Synthesis and characterization of new aromatic polyamides bearing crown ethers and acyclic ethylene oxide units in the pendant structure. III. Benzo‐18‐crown‐6 systems and their open‐chain counterparts

“…Thus, the percentage of water uptake of our polyamides is determined by two opposing factors: (1) the number of polar groups per structural unit increases the uptake, and (2) the presence of larger oxyethylene sequences increases the number of ether groups and also the conformational mobility of these groups, facilitating their interaction with the amide moieties and thus reducing the percentage of available polar amide groups to interact with water, diminishing the overall water uptake. 39,40 The isothermal sorption of water at 65% relative humidity was measured, and the values were related to the polyamide structure. Table 4 shows the data obtained as the water absorption percentage for polyamides derived from the diacids C6 and P8.…”

Synthesis, characterization and thermal decomposition of poly(decamethylene 2,6-naphthalamide)

“…The commonly mentioned aromatic and semiaromatic polyamides can not be processed by melting method due to their high melting temperature and relatively lower decomposition temperatures [4][5][6]. Therefore, several approaches have been made through synthetic modification by the incorporation of flexible linkages [7,8], bulky pendant groups [9] and noncoplanar biphenylene moieties [10] into the polymer backbones.…”