Polymers aromatic amide type

In the ordered smectic or nematic phase, the rigid rods are arranged in parallel arrays that allow for close packing. The nematic phase is the most common type found with synthetic polymer molecules. The molecules long axes are parallel, but there is no layering. Aromatic polymer chains that have stiff ester or amide linkages are ideal. 

Lanthanide amides of the type (CsH4Me)2Ln OCN(Pr )2NPh (THF), Ln = Y, Er, Yb, have been synthesized and their activity in the polymerization of PhNCO tested. The Y complex showed good activity at 30 °C and yielded yellow solid polymers which consisted of 43% methanol-insoluble and 57% methanol-soluble fractions.420 The regio-and stereoselective polymerization of aromatic diynes catalyzed by lanthanide metallocenes such as... 

Poly(amide)s (PA)s that bear the sulfone group in the backbone have been described." These types of PA, which are based on 4,4 -bis-((3-carboxy-phenoxy)(p-benzoyl))-phenyl sulfone, c.f. Figure 7.7, or the corresponding 4-carboxy acid component" is amidized by an aromatic diamine, e.g., p-diaminobenzene. The direct polycondensation of a dicarboxylic acid with aromatic diamines uses triphenyl phosphite and pyridine. The introduction of m-structures increases the solubility of the polymers and leads to... 

Partially aromatic PAs are considered as poly(phthal amide)s (PPA)s, when at least 60% of the diacid component is constituted from aromatic acids, prevalently from terephthalic acid (TPA) or isophthalic acid (IPA) [ 1 ]. PPAs and some types of partially aromatic PAs are considered as high performance polymers. 

The two main commercial polyamides are nylon 6,6, produced by condensation polymerization of HMD and adipic acid (see Table 7.1), and nylon 6, an AB-type polymer, which is produced from caprolactam. Other commercial polyamides include nylons 4,6, nylon 6,12 (which are AA- and BB-type polymers) and nylon 11 and nylon 12 (which are AB polymers made from linear aliphatic amino acids containing 11 and 12 carbons, respectively) [1]. Polyamides are also produced using monomers with aromatic, rather than aliphatic segments. Polyamides that contain 85% or more of the amide bonds attached to aromatic rings are called aramids. Commercial examples include poly(p-phenyleneterephthalamide) or Kevlar and poly(m-phenyleneisoterephthalamide) or Nomex [23]. 

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