Oxybenzoate-ethylene terephthalate

Polyesters [2] find use in fibers [poly(ethylene terephthalate), poly(ethylene oxybenzoate), poly(ester ethers), poly(ester amides), etc.] [1], coatings (especially unsaturated polyesters) [4], plasticizers, adhesives, polyurethane base resins, films, etc. Cross-linked polyesters prepared from glycerol and phthalic anhydride (alkyd resins) have been reviewed [20], High-melting poly aryl esters have been investigated for high-temperature applications. 

C14H12 = 3,3 -dimethyl-4,4 -biphenyldiyl j) Mol- % ratio ethylene terephthalate to oxybenzoate... 

Fig. 16a and b. Phase diagrams of poly(ethylene terephthalate-co-oxybenzoate). a. Crystal melting temperatures b. Glass transition temperatures. All samples with two glass transitions are most likely two-phase samples. The black circles up to 63 mol- % represent one-phase samples. Filled triangles W. J. Jackson, Jr. and H. F. Kuhfuss, J. Polymer Sci., Polymer Chem. Ed. 14, 2043 (1976). Open triangles R. W. Lenz and K. A. Feichtinger, Polymer Preprints, Am. Chem. Soc. Div. Polymer Chem. 20, 114 (1979). Filled circles Ref. 20). Open circle J. Menczel and B. Wunderlich, J. Polymer Sci, Polymer Phys. Ed., 18, 1433 (1980)... 

Hashimoto et al. [132] studied the fluorescence of the MCLC polyesters, poly[(ethylene terephthalate)-co-(p-oxybenzoate)], 66, and poly[(ethylene 2,6-naphthalene dicarboxylate)-co-(/ -oxybenzoate)], 67. The fluorescence of 66, both at relatively high concentration (5 x 10 3 mol dm-3) in hexafluoro-2-propanol,... 

Copolyesters of poly(ethylene terephthalate) and 4-acetoxybenzoic acid (PET / oxybenzoate) were synthesized by Jackson et al. through high temperature melt transesterification. However intricate details pertaining to the polyesterification kinetics have remained unexamined. In this system, insertion of 4-oxybenzoate moieties, with stiff rod like conformations, into flexible PET chains fosters the development of thermotropic character within a definite range of copolyester composition. 

Meesiti W, Menczd J, Gaur U, Wunderlich B (1982) Phase transitions in mesophase macromolecules. IIL The transitions in poly(ethylene terephthalate-co-p-oxybenzoate). J. Polymer Sd., Polymer Phys. Ed. 20 719... 

EI-MS was used to analyze an aromatic copolyester with units of p-oxybenzoate (PO) and of ethylene terephthalate (ET). The El mass spectra were recorded up to 480°C. At these temperatures, the chain cleavage is totally selective, since PO units are stable and ET units are not. Chain statistics was applied to the El mass spectra and a good agreement was foimd between the computed and the known composition. ... 

Shinn Ted-Hong, Lin Chen-Chong, Lin David, C. (1995). Studies on Co [Poly( Ethylene Terephthalate-p-oxybenzoate)] Thermotropic Copolyester Sequence Distribution Evaluated from TSC Measurements. Polym, 36(2), 283-289. 

The three-phase structures 12, 13, and 14 are of particular interest because of the even more severe violation of the phase rule. At constant pressure, in equilibrium, only one-phase areas should be stable. Drawn fibers of poly(ethylene terephthalate) (PET) are discussed as three-phase sttucture with Figs. 5.68-72 and 5.113-115. As in polyethylene, the drawing to fibers or films orients the amorphous nanophase and achieves an arrested mesophase order, proven with Fig. 5.72. Since the drawing of PET fibers is much less efficient in extending the molecules than gel-spinning, there remains a sizeable portion of the amorphous phase, as shown in Fig. 5.71. The mobile mesophase of PET has not been found as a stable phase, as in polyethylene. Copolymers of PET with stiffer repeating units, such as oxybenzoate, however, have stable mesophases (see Chap. 7). 

In this section, copolymers of polyethylene are discussed, starting with low-density, branched polyethylene and culminating with crystallization, melting, and annealing of poly(ethylene-co-octene-l), also described as linear-low-density polyethylene, LLDPE. Furthermore, partial phase diagrams of poly(ethylene terephthalate-co-oxybenzoate), PETcoOB, andpoly(oxybenzoate-co-oxynaphthoate), POBcoON, are presented. The latter systems are examples of increasing chain stiffness by cocrystalUzation which leads to mesophase behavior (see Sect. 5.5). 

PETcoOB and POBcoON. A second example of thermal analysis of copolymers involves the two systems, poly(ethylene terephthalate-co-oxybenzoate), PETcoOB, and poly(oxybenzoate-co-oxynaphthoate), POBcoON. The structural formulas of the CRUs are as follows ... 

Of special importance is in this case that the backbone of the copolymer can change chemically by trans-esterification (see Fig. 3.47). In fact, heating poly(ethylene terephthalate) and acetoxybenzoic acid in the melt is a common synthetic route to PETcoOB. The inclusion of oxybenzoate groups makes poly(ethylene terephthalate) increasingly stiffer (see Fig. 1.50). In POBcoON, oxynaphthoate adds an additional off-set of the large zig-zag of the benzoate. As a result of this chain stiffening, the PETcoOB with more than 30 mol-% oxybenzoate shows an anisotropic melt, as for a nematic main-chain liquid crystal (see Fig. 5.136) and the system POBcoON has a mesophase character over the whole concentration range. 

G aee Transition and Phase Diagram of Foly(ethylene Terephthalate-co-oxybenzoate)... 

X.-G. Li, M.-R. Huang, G.-H. Guan, and T. Sun, Kinetics of thermal degradation of thermotrr ic poly(p-oxybenzoate-co-ethylene terephthalate) by single heating rate methods. Polymer International, 46,289 (1998). 

Oxybenzoate-co-ethylene terephdialate Single Tgi Jm-depression II had 40 mol% ethylene terephthalate Ho et al. (2000)... 

Styrene/a-methyl styrene Styrene/(halogenated styrene) Styrene/(halogenated styrene) a-methylstyrene/acrylonitrile a-methylstyrene/methacrylonitrile Butadiene/acrylonitrile Butadiene/acrylonitrile (methyl methacrylate)/(alkyl methacrylates) (methyl methacrylate)/esters (glycidyl methacrylate)/(ethyl acrylate) (ethylene terephthalate)/oxybenzoate (ethyl acrylate)/(4-vinyl pyridine) Ethylene/(vinyl acetate)... 

Poly(ethylene terephthalate-co-p-oxybenzoate) Poly(ethylene terephthalate-co-4,4 -bisphenyl dicarboxylate)... 

All of the reactions listed above can be equally applied to the preparation of aromatic copolyesters from almost any combination of hydroxyacids, dicarboxylic acids and biphenols of the types listed in Table 3. In general, the copolymers so obtained are random or statistical in composition. Furthermore, the acidolysis reaction has been successfully applied to preparation of random copolyesters by interchanging monomers and high molecular weight polymers, most notably in the preparation of poly(ethylene terephthalate-co-oxybenzoate) by the insertion reaction of /7-acetoxybenzoic acid with preformed poly(ethylene terephthalate), as follows... 

Blocks 2 can be poly(oxytetramethylene), a semifluorinated polyester, poly-[(ethylene terephthalate)-co-oxybenzoate], a polyesterimide and a poly(ethylene terephthalate)-co-polyesterimide. The structure of the copolymer polysulfone- -polyoxytetramethylene is given as an example in Scheme 6. 

Bohme F, Leistner D and Baier A (1995) Comparison of the coupling behaviour of diisocyanate and bisoxazolines in modification of liquid crystalline poly(ethylene terephthalate-co-oxybenzoate)s, Angew Makromol Chem 224 167-178. 

Recently Kresse and colleagues reported preliminary results of DR studies on yet another type of LCP derived from PET. They diluted the ethylene terephthalate units in a chain by adding (in 1 1 molar ratio) n-pentane-l,5-diyl-4-oxybenzoic acid (A) and l,4-bis(4-acetoxybenzoyloxy)benzene (B). As a result, random copolymers PET Aj,/2 Byj2 were obtained, which for x 80% form 9 nematic phase on melting. Measurements were performed for five different compositions of the copolymer, (x, y) = (20, 80), (40,60), (60,40), (70, 30) and (80,20) per cent, and for pure PET for comparison. The DR measurements were carried out in the very broad frequency range 1 Hz-1 GHz, and over a... 

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