Aromatic polyesters and copolyesters

PCT obtained from commercial 1,4-CHDM with a cis/tmns ratio of 30/70 is highly crystalline, with T = 290 °C and = 90 °C (11). The melting temperature of PCT decreases almost linearly as the content on cis isomer increases from 0 to 100% (12,34,35). Both melting temperature and enthalpy of PCT may be therefore tuned by adjusting the 1,4-CHDM isomeric ratio. Turner et al. (11) reported that the cis/trans ratio also affects the barrier properties of PCT with the permeability to oxygen decreasing with the content in cis isomer. 

PCT with a random distribution of cis and Irans 1,4-CHDM isomeric units evolves to a blocky microstructure upon annealing the polymer near below its melting temperature (36). This behavior is attributed to the occurrence of ester interchange reactions favored by the generation of homogeneous stereoblock segments able to crystallize. 

In general PECT copolyesters are obtained by the two step melt polycondensation process from terephthalic acid (PTA) or DMT and mixtures of EG and 1,4-CHMD. The use of specific catalysts enabling the preparation of colorless PECT with high molecular weight has been reported (11,41-43). 

The PECT copolymer composition including the isomeric cis/tmns ratio can be determined by H-NMR. The sequence distribution can 

If BD is replaced by 1,6-hexanediol, the poly(hexamethylene-co-1,4-cyclohexylenedimethylene terephthalate) random copolyesters 

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Makromolekulare Chemie 194, No.6, June 1993, p.1545-59 LEVEAR-TEMPERATURE PROGRAMMED PYROLYSIS OF THERMORESISTANT POLYMERS - MASS AND FTIR SPECTROMETRIES. II. AROMATIC POLYESTERS AND COPOLYESTERS Hummel D 0 Neuhoff U Bretz A Duessel H J Koln,Universitat Angewandte Spektrometrie Koeln eV... 

Various low molecular weight polyesters are polymeric plasticizers. These are likely to be compatible with polyester resins. Other groups of plasticizers are also used in plasticization of aliphatic and aromatic polyesters and copolyesters, as follows ... 

D. O. Hummel, U. Neuhoff, A. Bretz, and H.-J. Dussel, Linear-temperature programmed pyrolysis of thermoresistant polymers—mass and FTIR spectrometries, 2, Aromatic polyesters and copolyesters, MakromoZ. Chem., 194, 1545 (1993). 

Aliphatic polyesters and copolyesters Aromatic polyesters and copolyesters Poly(caprolactone) - PCL Poly(esteramide)s - PEA Poly(vinyl alcohol) - PVA... 

Aliphatic and aromatic polyesters and copolyesters containing cyclohexanedimethanol units are reviewed covering from the synthesis of monomers up to their polymerization by the different known synthetic routes. Thermal and mechanical properties as well as thermal and chemical stability are discussed with reference to the polyester structure. Compounding, processing, recycling and applications of these polyesters and copolyesters are also reviewed. Finally, an account on the recent developments in blends and composites is provided. 

Since the discovery of 1,3- and 1,4-cyclohexanedimethanol, the interest in these monomers for the production of polyesters has gradually increased. Today they are frequently used for the synthesis of both aliphatic and aromatic polyesters and copolyesters, which distinguish by showing novel improved properties. 

Table 6.3 summarizes the mechanical properties of some aromatic polyesters and copolyesters derived from 1,4-CHDM. 

The mechanical properties of the UPR prepared using pentaerythritol diacetate were comparable with the properties of a commercial UP resin (Table 10). Novel unsaturatedpara-linked aromatic polyesters and copolyesters (Scheme 11) containing fumaroyl units were synthesized by the interfacial... 

A great many aromatic polyesters and copolyesters which show thermotropic behaviour have now been reported, particularly in the patent literature. The copolyesters may contain either combinations of different types of mesogenic units or combinations of mesogenic and non-mesogenic (non-linear) units. The structures of many of the different types of monomers used to form liquid crystal aromatic polyesters and copolyesters are shown in Table 3. ... 

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