Aromatic Polyamides

Abstract

This article presents the preparation and properties of aromatic polyamides as well as the fibers and films made from these polymers. Particular focus is placed on the polymers that have achieved commercial status, namely, poly( m ‐phenylene isophthalamide), poly( p ‐phenylene terephthalamide), and copoly( p ‐phenylene/3,4′‐diphenyl ether terephthalamide). The production processes of the corresponding monomers for these three polymers are described in detail, analyzing both laboratory and commercial‐scale processes for the preparation of the polymers in the form of fibers and films. A brief review of new developments in the synthesis and applications of functional aromatic polyamides is also given, analyzing new applications in which polyamides are being employed, such as electronics, sensors, and biomaterials. Finally, a brief analysis of the economic impact of the polyamide market is described, including also environmental aspects.

Porous aromatic polyamides the easy and green way

“…However, the commercially important aramids nowadays is reduced to poly(m-phenylene isophthalamide) (MPIA) and poly(pphenylen terephthalamide) (PPTA), due to their outstanding properties combined with their low density. [1] Current research efforts are directed into the improvement of the properties of these materials, [2] including lowering their weight without impairing their high-performance properties, which is important for applications related to the aeronautic and automotive industries and in human protection clothing. The preparation of polymers with cellular structure is a means for lowering the weight of materials.…”

Dynamic Mechanical Analysis and Thermal Expansion of Lignin-Based Biopolymers

“…A second, much lower peak can be observed with a centered tanδ at 0.18 and a temperature of 86.52 °C, which can be associated with a transformation that occurs in the material structure during its progressive heating, most likely to be water evaporation and/or the decomposition of natural additives or dyes [ 15 ]. On the damping curve, no transition that could be associated with the reinforcement—aramid fibers—is noticed, as it is thermally stable up to 450 °C [ 16 ], well above the range set for this analysis, and the glass transition of the aramid fibers appears in the (345–360) °C temperature range, [ 17 ]; otherwise, there are only losses of hydrogen bonds; On the damping curve, around the 145 °C temperature mark, an ascending slope appears, which indicates the beginning of the material softening—the flowing zone— which according to reference [ 18 ], has a melting point at 171 °C; The damping peak is narrow and sharp and the descending E′ slope is steep, which indicates that the chemical structure of the material is homogeneous, and the transition takes place in a short time and temperature range; The rubbery plateau region is in the 96–148 °C temperature range. …”

“…A second, much lower peak can be observed with a centered tanδ at 0.18 and a temperature of 86.52 °C, which can be associated with a transformation that occurs in the material structure during its progressive heating, most likely to be water evaporation and/or the decomposition of natural additives or dyes [ 15 ]. On the damping curve, no transition that could be associated with the reinforcement—aramid fibers—is noticed, as it is thermally stable up to 450 °C [ 16 ], well above the range set for this analysis, and the glass transition of the aramid fibers appears in the (345–360) °C temperature range, [ 17 ]; otherwise, there are only losses of hydrogen bonds;…”

“…Additionally, the α* transition is used by manufacturers to optimize the material properties. The semi-crystalline structures of the materials are attested by XRD (X-ray Diffraction) analyses performed and published previously, [ 13 , 17 , 20 ].…”

Graphene/graphene nanoplatelets reinforced polyamide nanocomposites: A review

“…25 The proteins, wool, silk are natural, whereas aliphatic polyamides or nylons and aromatic polyamides or aramids are synthetic PAs. 26 The PAs have a wide range of applications encompassing excellent features such as lightweight, durability, easy fabrication, relatively low cost, stiffness, and higher heat resistance. The common examples of PAs are PA6 (Nylon 6), PA11 (Nylon 11), PA66 (Nylon 66), PA610 (Nylon 610), PA612 (Nylon 612), etc.…”