Crosslinked Aromatic Polyamides: A Further Step in High‐Performance Materials

Abstract

This work aims to improve the outstanding thermal and mechanical properties of commercialized wholly aromatic polyamide fibers (i.e., aramids), by crosslinking the materials. The introduction of a reactive azide group into the polymer structure leads to functional aramids. Crosslinking processes can be easily performed using an inexpensive thermal treatment after fiber spinning with current spin production facilities.

Intrinsically colored wholly aromatic polyamides (aramids)

“…The mechanical properties were similar to those of the reference m-aramid, MPIA, with tensile strength and Young's modulus of 51 and 1530 MPa, respectively, with elongation of 5% [9]. At this point, it is important to take into account that the measurements were carried out with lab-made un-oriented and thermally un-treated films prepared by casting.…”

Functional Aromatic Polyamides

“…At the same time, both the dry density and the hydrophilicity of the films decreased with increasing fabrication temperatures, caused by crossover reaction induced by temperature, and the aggregation of the hydrophobic and hydrophilic units to minimize the surface energy and suppress hydrogen bonding. Heat can also produce crosslinking of polymeric chains as a way of improving their thermal and mechanical properties without impairing other properties, as Trigo-López [161] and coworkers demonstrated. They prepared a series of polyamides and copolyamides with reactive azide groups from m-phenylene diamine 5-azidoisophthaloyl chloride (Scheme 45, P72-P73).…”

“…The potential of the parent aramids was exemplified by the preparation of polyamides with side chains containing different functionalities such as a fluorescent dansyl group P73-5, anion and cation receptors group urea and triazole with primary alcohol functional groups (P73-6, P73-3), and the iminophosphorane ligand for forthcoming synthetic processes (P73-4). Heat can also produce crosslinking of polymeric chains as a way of improving their thermal and mechanical properties without impairing other properties, as Trigo-López [161] and coworkers demonstrated. They prepared a series of polyamides and copolyamides with reactive azide groups from m-phenylene diamine 5-azidoisophthaloyl chloride (Scheme 45, P72-P73).…”

Aromatic polyamides and acrylic polymers as solid sensory materials and smart coated fibres for high acidity colorimetric sensing

“…Acidity or basicity in aqueous media is usually monitored using the standard pH scale, which ranges from 1 to 13, 1 by different techniques that perform well in covering most of the laboratory requirements. These polymers have a high-performance aromatic polyamide main structure [11][12][13][14] or an acrylic nature with gel behaviour, [15][16][17][18] which can be prepared or transformed into highly manageable materials including films, membranes, or coatings for cotton commodity or high-tech meta-or para-aromatic polyamide fibres. Less extensively used are chemical pH sensors.…”