Naphthalene thermotropic polyesters

DuPont workers have described (7) a wide variety of tractabilizing molecules and the thermotropic polyesters derived therefrom. Their research has focused for the most part on ring substituted monomers such as chloro, methyl or phenyl substituted hydroquinone and swivel" or linked ring molecules, examples of which are 3,4 or 4,4 functionally (hydroxy or carboxy) disubstituted diphenyl ether, sulfide or ketone monomers. Use of the parallel offset or crankshaft" geometry provided by 2,6 functionally disubstituted naphthalene monomers has been the major thrust of the Celanese Corporation development of easily processed, high performance wholly aromatic thermotropic polyesters. 

Specifically, Celanese has defined families of thermotropic polyesters derived from 2,6-naphthalene dicarboxylic acid (NOA), 2,6-dihydroxynaph-thalene (DHN) or 6-hydroxy-2-naphthoic acid (HNA). Indeed, the Vectra LCP engineering resins of Celanese Corporation are based on these monomers. 

Composition/Tm Relationships of Naphthalene Derived Thermotropic Polyesters... 

Wholly aromatic thermotropic polyesters were developed soon after by Celanese, who defined families of copolymers based on 2,6-naphthalene... 

The aromatic semiflexible polyesters can be formed by varying the dicarboxylic multi phenyl acid structure (naphthalene and diphenol) and non-linear aromatic diol (3,4 -dihydroxybenzophenone). 3,4 -dihydroxybenzophenone can be synthesized from 4-methoxy bromobenzene and m-methoxybenzonitrile via multistep reaction, which can be condensed with respective diacid chloride in o-dichlorobenzene at reflux temperature [43]. It is well known that dimethyl siloxane spacer can make a flexible/semiflexible LC polymer. Thermotropic flexible liquid-crystalline main chain polyesters... 

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