2-hydroxy-6-naphthoic

Among the commonly used monomer units are hydroxybenzoic acid,p-tereph-thalic acid, 2-6-naphthalene dicarboxylic acid, 2-hydroxy-6-naphthoic add, and 4,4 -biphenol. Thus, polymers can be prepared from simply one unit, as with poly(p-hydroxybenzoic acid) ... 

Suppliers and commercial grades are shown in Table 16.7. Monomers and structural units used in commercial available LCPs have been sununarized in the literature. Vectra types are random copoly(ester)s based on HBA and 2-hydroxy-6-naphthoic acid or copoly(ester amide)s based on 4-aminophenol and TPA. Xydar types are fully aromatic poly(ester)s based on HBA, BP, and TPA. Neat poly(ethylene terephthalate), is not a LCP. However, by the introduction of HBA it becomes a LCP. The ethylene groups act as flexible spacers that reduce the nematic transition temperature. Commercial available types of this kind are X7G and Rodrun types. Tradenames appearing in the references are shown in Table 16.8. 

X-ray diffraction patterns of fibers spun from liquid crystalline melts of p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) show a high degree of axial orientation. Several meridional maxima are detected which are aperiodic and also change in position and number with the monomer composition. The positions of these maxima can be predicted by calculating the theoretical scattering of random copolymer chains, in which the residues are represented by points separated by the monomer lengths. Both peak positions and intensities are reproduced when intraresidue interferences are allowed for in an atomic model for the random chains. This procedure also allows determination of the stiff-chain persistence (or correlation) length from the breadth of the maximum at d=2.lA which increases from 9 to 13 residues as the HBA content is increased from 25 to 75%. 

Copolymerization of several mesogenic monomers such as p-hydroxy-benzoic acid (PHB) or 2-hydroxy-6-naphthoic acid produces random copolymeric structures with depressed melting points. ... 

Vectra p-Hydroxy benzoic acid/ 2-Hydroxy 6-naphthoic acid 120 [9]... 

Vectra B950 LCP copolymer comprising 20 mol% of terephthalic acid, 20 mol% 4-aminophenol, and 60 mol% of 2-hydroxy-6-naphthoic acid Hoechst Celanese Corp. 

HBA, 4-Hydroxybenzoic acid HNA, 2-Hydroxy 6-naphthoic acid TA, terephthalic acid DHN, 2,6 dihydroxynaphthalene BP, 4,4 biphenyldiol. 

The DSC curve of Vectran fiber, which is a random copolymer of p-hydroxy-benzoic acid (HBA), and 2-hydroxy-6-naphthoic acid (FINA), shows a very broad glass transition at -100 °C, and an extremely broad melting peak... 

DSC has been used to measure T on a variety of polymers including naphthalate copolymers [111,112], polyethylene terephthalate-5-nitrosophthalic acid copolymers [113], propene-pentene copolymers [114], 4-hydroxy benzoic acid-2-hydroxy-6-naphthoic acid copolymers [115], fluorinated perfluorocyclo butylenes [116], PET [117], polythioether ether ketones [14,104], polyvanillylidiene, alkyl/aryl phosphate esters [118], poly(L-lactic acid-poly(e-caprolactone) [119], benzylated waste pulp-L-lactic acid copolymers [120], PET - poly-1,4 butylene succinate [121], polyarylate-polytrimethylene terephthalate [122], polyimines [77], PVOH [123, 124], various Nylons [125]. 

Davies, G.R. and Ward, I.M. (1988) Structure and properties of oriented thermotropic liquid crystal polymers in the solid state, in High Modulus Polymers (eds A.E. Zachariades and R.S. Porter), Marcel Dekker, New York, Chap. 2 Troughton, M.J., Davies, G.R. and Ward, I.M. (1989) Dynamic mechanical properties of random copolyesters of 4-hydroxybenzoic acid and 2-hydroxy 6-naphthoic acid. Polymer, 30, 58 Green, D.I., Unwin, A.P., Davies, G.R. and Ward, I.M. (1990) An aggregate model for random liquid crystalline copolyesters. Polymer, 31, 579. 

HBA-HNA BCP HBA-HNA BCP Transesterification of p-hydroxybenzoic acid-co-2-hydroxy-6-naphthoic acid (HBA-HNA) TCP s of differing composition followed by X-ray diffraction 273... 

Flodberg and co-workers [22] report that the two monomers, p-hydroxy benzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) present in poly(p-hydroxybenzoic acid-co-2-hydroxy-6-naphthoic acid are now included in the positive list of the new Commission Directive 2002/72/EC [2]. In the former Directive 91/128/EC [1], these two monomers were not included in the positive list and, therefore, could not be used for applications involving direct contact with food. 

The high performance LCP (HP-LCP) was made of copolyester of 2-hydroxy-6-naphthoic acid (HNA), hydroquinone (HQ), 2,6-naphthalene dicarboxylic acid (NDCA) and terephthalic acid (TA). HNA and NDCA were selected as naphthalene moiety because of imparting hydrolysis resistance to copolyester. Isophthalic acid (lA) was not used as one of the components because it was observed that the lA moiety, a bent-shaped monomer, deteriorates hydrolysis resistance. The ratio of HQ was specifically selected for adjusting the target melt viscosity of the copolymer. The level of heat resistance depends mainly on the ratio of both TA and HQ. Although many TLCPs have been developed and each commercial TLCP has a different combination of monomers, the composition of the HP-LCP... 

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