Terephthaloyl unit

In regioregularly substituted RR-BH the bromine substituents are located only on the terephthaloyl unit, whereas in RR-BB both the two structural units contain the substituents. If one polymerizes bromoterephthalic acid with hydroquinone or bromo-... 

In the last few years, Hamilton has published reports of a series of open chain or cyclic receptors featuring 2-acylaminopyridine units as combined H-bond donor and acceptor groups [30]. The simple terephthaloyl derivative 22 forms stable complexes with dicarboxylic acids of appropriate chain length, like adipic and glutaric acid, in CDCI3 [31]. Additionally, complexation influences the s-cis s-trans ratio of the amide bond in acylprolines [32]. 

In this study, polyesters [XII] having syringyl-type biphenyl units were synthesized from 4,4 -dihydroxy-3,3, 5,5 -tetramethoxybiphenyl (XI) which was prepared from 2,6-dimethoxyphenol (11). As shown in Scheme 6, poly esterification of XI with terephthaloyl, isophthaloyl and sebacoyl chloride were carried out by the low temperature solution polycondensation and by the interfacial polycondensation. The polyterephthalate with jjinh = 1.42 dl/g was obtained by the interfacial poly condensation. The polyisophtha-late with f7 nh = 0.73 dl/g and the polysebacate with Jj nh = 0.43 dl/g were obtained by the low temperature solution polycondensation. 

The second synthetic route to PAE containing quinoxaline units involved the reaction of an aromatic dihydroxy quinoxaline or aromatic bis(hydroxy-quinoxaline) with activated aromatic difluoro compounds (Eq. (3)) [15]. The dihydroxy quinoxaline and bis(hydroxyquinoxaline) monomers were readily prepared from the condensation of 1,2-diaminobenzene with 4,4 -dihydroxyben-zil and aromatic bis(o-diamines) with 4-hydroxybenzil, respectively. The Tgs of a series of PAE containing quinoxaline units are presented in Tables 3 and 4. For these polymers, the trend for the Tg is sulfone > carbonyl > terephthaloyl-> isophthaloyl. This trend holds for most polymer families when polymers of similar molecular weights are compared. Several polyphenylquinoxalines of the same chemical structure as those in Table 3 were also prepared by the poly-... 

All ester groups in the PET chain are assigned confidently to be planar trans. The restriction of bonds 1 and 3 to the trans states and bond 2 to a choice between cis and trans leads to the simple statistical weight matrices. The length of the span of the terephthaloyl residue in PET guarantees independence of the conformations of successive repeating units of the chain. 

Polyesters 26 represent the first ferrocene-containing liquid crystal polymers [28]. These copolymers were found to be insoluble in THF, toluene, dichloromethane, chloroform, p-chlorophenol, and tetrachloroethane. The terephthaloyl chloride/iso-phthaloyl chloride ratio was maintained constant (7 3), but the content of the ferrocene unit was varied from 0 to 100%. 

On the other hand, in the ordered sequence copolymer of Equation 23, all of the 4-oxybenzoyl moieties exist in a monomeric unit and, thus, every linear triad segments consisting of 4-oxybenzoyl-terephthaloyl-4-oxybenzoyl links are interrupted by the bent 1,6-naphthalene moieties that destroy the linear geometry of the chain. Although we have discussed only one representative example, similar phenomenon and explanations should apply to other systems of the same structural characters. 

Structure Level I. Structure Level I variations for aromatic polyamides are broad. The wide range of segmental structures possible with these polymers is what makes them so interesting for membrane science. The discussion of Structure Level I will be limited to some representative segmental units in polyamides, polyhydrazides and polyamide-hydrazides. Structures and abbreviations for some typical diamines that are condensed with mixtures of isophthaloyl chloride (l) and terephthaloyl chloride (T) to give the aromatic polyamides discussed in this paper are shown in Table III. 

Poly(ether-ester)s have been prepared by condensation of adipoyl or terephthaloyl chloride with an isosorbide-based ether-diol (Scheme 3.10). The parent isosorbide is obtained from renewable resources, hydrogenation, and subsequent dehydration of D-glucose. The polymerizations were accelerated about five times under microwave heating using a scientific microwave unit as compared to conventional methods, and a 95% yield of the desired polymers was obtained within 5 min at 180 °C. 

These premises can be taken as the major reasons for the rationale that brought us to contribute to meetings, such as the first and the second Joint Polish-Italian Seminar, expressely devoted to "polymer blends". In this context, we present the results of the work done in part at the University of Pisa and in part at the University of Massachusetts in the field of the preparation and characterization of polyester systems containing p-oxybenzoate residues, as the anisotropic moieties, embedded in structurally ordered macro-molecular segments. Linking units in the hard segments are the terephthaloyl (Series I, IV, and V), oxalyl (Series II) and carbonyl... 

The trivial names are retained for diradicals occurring often. Consequently, —CH2CH2— is called ethylene and not dimethylene, the unit —CH2CH(CH3)— is propylene and not 1-methyl ethylene, and the unit —OC—C6H4—CO— is known as terephthaloyl and not carbony 1-1,4-phenylene-carbonyl or oxo-l,4-phenylene-oxo (Example 7 in Table 2-2). 

Figure 4.5 Sequential functionalisation methodology for the covalent modification of MWNTs with one and a half repeat units of Kevlar. (A) PDA-MWNTs, (B) TPC-PDA-MWNTs, and (C) PDA-TPC-PDA-MWNTs bottom panel the schematic presentation of functionalised MAVNTs and corresponding TEM image. TPC- terephthaloyl chloride PDA- p-phenylenediamine. Reproduced with permission from Sainsbury et al.

The OS-Ar-8 polymer is an alternating copolyester consisting of oxy-l,4-phenyleneoxy-terephthaloyl(PT) and oxy-l,4-phenyleneoxydecanoyl(PD) units. In contrast, the OS-10-8 polymer is a terpolyester having a sequential order of oxy-l,4-phenyleneoxy-terephthaloyl(PT), oxy-l,10-decamethyleneoxyterephthaloyl (PT) and oxy-l,4-phenylene-oxydecanoyl (PD) units. 

The polyarylate (PAr) used is composed of bisphenol-A (BPA) units with a mixture of terephthaloyl (TP) and isophthaloyl (IP) units (molar ratio BPA TP IP = 2 1 1). PAr is a commercial product of Union Carbide Co., with the trade name of RDEL-DIOO. 

Havens and Reimer have used carbon-13 NMR measurements to study the sequence distribution in a series of aryl ether ketone copolymers [41]. These copolymers were based on terephthaloyl chloride (T), 1,4-diphenoxy-benzene (B), and diphenyl ether (E) and were prepared by a Friedel-Crafts reaction using either HF/BF3 or buffered AICI3 as the catalyst. The copolymers formed are comprised of T units alternating with either E or B units. 

A thermally stable system containing phenylene oxide units in the main chain, prepared by polycondensation of 2,2 -bis[4-(p-aminophenoxy)] phenyl propane and terephthaloyl chloride, has also been studied, and systems containing sulphone-ether units have also been investigated. ... 

A type of aromatic-aliphatic liquid crystalline copolyesters has been synthesized from 2-chlorohydroquinone, 1,4-CHDM and terephthaloyl chloride (Figure 6.14). The CHDM units act in these copolyesters as flexible spacers providing the necessary chain mobility to be thermotropic. The structure and thermal behavior of these copolyesters were characterized by hot-stage polarized light microscopy, SEM, FTIR, NMR, DSC and TGA (57). It has been reported that they are insoluble in common solvents and may form mesophases at temperatures near the melting temperature of PET (58). 

Other Extended Chain Polyhydrazides. The polyhydrazide system based on terephthaloyl, chloro-terephthaloyl, 2,5-pyridinedioyl and oxalyl units was examined by the preparation of polymers and determination of their ability to form liquid crystalline solutions in aqueous tetramethylammonium hydroxide. The acyl groups are coded T, ClT,... 

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