Heterocycles aromatic polyesters

Further studies of the Yokozawa group concerned CCPs of aromatic polyesters. At first, polymerizations of 4-trimethylsiloxybenzoyl chloride and its anion (see Formula 16.7), first reported by Yokozawa et al. [110] were studied Yet the insolubility of poly(oxibenzoate) in aU inert solvents prevented a satisfactory characterization of the reaction products [111]. Therefore, a new class of monomers (see Formula 16.7d) was synthesized. The aliphatic side chains rendered the polyesters soluble in various inert solvents, and the activated heterocyclic amid group eased purification by recrystallization To prevent transesterilication the polymerization temperature had to be lowered to 30 °C [112, 113]. 

BDS) craig polyester for alcohols, aromatics, heterocycles, fatty acids and esters, hydrocarbons Tetraethylene glycol dimethylether... 

The purpose of this work was to correlate catalytic activity with chemical structure for various aromatic and heterocyclic carbonyl compounds. Gel time, gel time as a function of initiator concentration, and gel time as a function of temperature were used to measure catalytic activity for the unsaturated polyester styrene systems used throughout this work. 

A reduction of the melting temperatures of aromatic LC polyesters can also be accomplished efficiently by the partial incorporation of kinked comonomers. Suitable monomers are meta- or ortho-functionalized benzene rings, meta- or ortho-functionalized six-member heterocycles, and 2,5-func-tionalized five-member heterocycles. A frequently used alternative is two benzene rings connected by linking groups such as... 

The novel polymers (end of 1960s and early 1970s) belong mostly to the HT group and their overall utility is limited. Many appear as special fibers, like aromatic polyamides and polyesters, polyimides and Parylene. The novel structures have rings (either aromatic or heterocyclic), in the main chain (para-phenylene is preferred over meta-phenylene). Substituting C—H bonds... 

Table 1. Polyester Formation from Aromatic Heterocyclic Diacids or Diesters, and Ethylene Glycol... 

The chemistry involved in curable poly(ester imide) formulations is well established, and it is still based on trimellitic anhydride, methylene dianiline, and low molecular weight polyesters of aromatic dicarboxylic acids and glycols, along with a classical heterocyclic triol, 2,4,6-trishydroxyethyl isocyanurate (THEIC), as it is shown in Scheme (29). The composition is formulated in a way that the final polymers, although linear, contain free —OH groups, both as chain ends and as side reactive groups. At the moment of... 

Simultaneous chain growth and crystal growth (SCCG) are characteristic for crystalline, high melting aromatic polymers which are insoluble in most, if not in aU, reaction media. Such polymers include polyesters, polyamides, polyimides, and other polymers based on heterocyclic monomers. The Tm s are above 400 °C and in most cases above 500 °C, so that even trimers or tetramers may have Tm s above 300 °C. Polycondensations in bulk may be feasible, when the monomers... 

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