Polyamides with Special Properties

Condensation polymers are classified as polyesters, polyamides, polyurethanes, and ether polymers, based on the internal functional group being ester (-COO-), amide (-CONH-), urethane (-OCONH-), or ether (-0-). Another group of condensation polymers derived by condensation reactions with formaldehyde is described under formaldehyde resins. Polymers with special properties have been classified into three groups heat-resistant polymers, silicones and other inorganic polymer, and functional polymers. Discussions in all cases are centered on important properties and main applications of polymers. 

Diamantane-based polymers are synthesized to take advantage of their stiffness, chemical and thermal stability, high glass transition temperature, improved solubility in organic solvents, and retention of their physical properties at high temperatures. All these special properties result from their diamantane-based molecular structure [90]. Polyamides are high-temperature polymers with a broad range of applications in different scientific and industrial fields. However, their process is very difficult because of poor solubility and lack of adequate thermal stability retention [90]. Incorporation of 1,6- or... 

Many properties of polyamides are attributable to the formation of hydrogen bonds between the NH and CO groups of neighboring macromolecules. This is evidenced by their solubility in special solvents (sulfuric acid, formic acid, m-cresol), their high melting points (even when made from aliphatic components), and their resistance to hydrolysis. In addition, polyamides with a regular chain structure crystallize very readily. 

The decorative laminates described in the previous chapter are made with selected thermosetting resins while resins of this type can be moulded and extruded by methods similar to those outlined in the present and the next chapter the materials employed for these processes predominantly are thermoplastic. Many such plastics can be moulded and extruded under suitable conditions, the most important in terms of quantities used being those that combine properties satisfactory for the purpose with convenience in pro-cessing-especially the polyolefins (polyethylene and polypropylene), poly(vinyl chloride), and styrene polymers and blends. Other plastics with special qualities, such as better resistance to chemical attack, heat, impact, and wear, also are used—including acetals (polyformaldehyde or polyoxymethylene), polyamides, polycarbonates, thermoplastic polyesters like poly(ethylene terephtha-late) and poly(butylene terephthalate), and modified poly(phenylene oxide),... 

In addition, isosorbide and other l,4 3,6-dianhydrohexitols (isomannide derived from D-mannose, isoidide derived from L-fructose) are also attractive to serve as monomers for polymer production due to their rigidity, chirality, and non-toxicity (Fig. 6). Such features may introduce special properties into the polymers formed, such as enhanced Jg and/or special optical properties. Their innocuous nature also opens the possibility of applications in packaging or medical devices. As a bifunctional monomer, isosorbide can be polymerized with other bifunctional monomers via condensation polymerization. A recent review described various isosorbide-based polymers synthesized, including polyesters, polyamides, poly(ester amide)s, poly(ester imide)s, polycarbonates, polyurethanes, and so on [308], and the present... 

The following tables and diagrams contain physical and physicochemical properties of common polymers, copolymers, and polymer blends. The materials are arranged according to increasing number of functional groups, i. e. polyolefines, vinyl polymers, fiuoropoly-mers, polyacrylics, polyacetals, polyamides, polyesters, and polymers with special functional groups [3.2-16]. 

Although Tyrann-M/E and even conventional membranes are superior to the new polyamide and polyfvinylidene fluoride) membranes with respect to flow rates and filtration capacities, the latter two are more suitable for filtration of most (but not all) organic solvents and, partially as a result of their lower void volumes (Table IV) exhibit mechanical and thermal properties which are generally superior to those of the cellulosics. It should also be noted that in the special case of fiber-reinforced membranes, the mechanical properties are predominantly functions of the embedded fibers rather than of the membrane structu reverse. 

Polyimide (PI) caps all other polymers in its temperature range of use (-200 to 260 °C in air short-time even up to 500 °C). Because of its high price, it is used in special cases only, such as space vehicles, nuclear reactors and some electronic parts. Newer developments, related to polyimide, are the polyether imides (e.g. Ultem ), polyester imides and polyamide imides (e.g. Torlon ), all with very good mechanical, thermal and electrical properties and self-extinguishing. 

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