Polyamide-imides polymer units

There are also a few common polymers whose accepted names convey relatively little information about the repeating unit structure. The primary examples are polycarbonate, poly(phenylene oxide), polyamide-imides, poly-sulfones, and polyether ketones (see Table 1.3). 

The dipole moment of a selected functional group in the polymer can also be calculated using the Clausius-Mossotti equation. According to Van Krevelan, (15) the "effective polarizability" of a functional group in the polymer is calculated from the measured dielectric constant, the polymer density and the number of moles of that group in the polymer repeat unit. Using the data for the six polyamide-imides listed in Table I, the effective polarizability of the amide group can be determined from... 

The synthesis and characterization of a photocrosslinkable liquid-crystal polymethacrylate with both biphenyl unit as a mesogen and styryl-2-pyridine unit as a photosensitive center in the same side-chain was described. Unsaturated polyamide-imides are light sensitive and can be crosslinked by UV radiation. The polymers consist of polyamide backbones and... 

A series of lyotropic poly(imide-amide)s were synthesised [39], in which an ordered unit comprising trimellitimide condensed with p-aminobenzoic acid andp-phenylene diamine (PPD) was copolymerised in varying ratios (0,50 and 80%) with a terephthalic acid/PPD polyamide. The MI predicts all three polymers to be LC, but lyotropic behaviour was observed in only the first one (Table 13). This is particularly surprising because incorporating increasing quantities of the known lyotropic and more linear TPA/PPD units would be expected to produce definite lyotropic behaviour. Similarly, a copoly(amide-imi-de) of 3,3 -dimethyl benzidene and 4-amino benzoic trimellitimide was predicted by the MI to possess a mesophase but none was detected. These apparent failures may be due to the fact that the polymers which did show lyotropic behav-... 

D.-J. Liaw, C.-C. Huang, W.-H. Chen, Color lightness and highly organosoluble fluorinated polyamides, polyimides and poly(amide-imide)s based on noncoplanar 2,2 -dimethyl-4,4 -biphenylene units. Polymer 47 (7) (2006) 2337-2348. 

Without the introduction of ladder-like moiety induced from benzodioxane, polyimides derived from distorted backbone units have potentials to retain the intrinsic microporosity because the imide linkage itself is formed as very rigid and flat two-dimensional structure. " Similar to Cardo-PIM, these polymers are based on bifluorene units, which have a 90° kink that prevents space-efficient packing or crystallization of the otherwise stiff polymer chains. Weber and Thomas synthesized bi-, tri- and tetra-functional bifluorene and reacted with dianhydride, di(acid chloride) or trimesoyl chloride for contorted polyimide and polyamide. The most microporous polyimide represents the BET surface area of 982 m g , providing much potential for highly permeable gas separation membranes. 

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