Isophthalate/terephthalate ratio polyesters

Extensive literature is available on the effects of the variation of the isophthalate/terephthalate ratio upon the melting behavior and solubility characteristics of the polyesters of bis-phenol a2 5,6 properties of the tetrachlorobisphenol A... 

A seemingly contradictory set of objectives exist when one attempts to optimize solution stability of a methylene chloride solution of a polymer while requiring a fiber, from that polymer, to be resistant to perchlorethylene (Perclene) dry cleaning solvent. Initial evaluations of fibers show that the CAPE and BRAPE polyesters are attacked by dry cleaning solvent when the isophthalate/terephthalate ratios lie in the range of 50/50 to 80/20. These combinations, which are required for solution stability also lead to a maximum in Perclene susceptability. 

A convenient method of compositional designation uses molar percentages of ester and carbonate linkages coupled with the molar percentages of iso- and terephthalate units in the polymer. A 70% ester, 30% carbonate polyester carbonate with 60 parts of isophthalate and 40 parts of terephthalate is designated 70(60/40)30. Similarly, a standard PC resin is 0(0/0)100, and a polyarjlate resin composed of a 1 1 molar ratio of iso- to terephthalate units esterfied with bisphenol A is designated 100(50/50)0. 

For convenience, the letters T (terephthalic acid), I (isophthalic acid), H [50/50 cw/trarw-hexahydroterephthalic acid (1,4-cyclohexane-dicarboxylic acid)], and NPG [neopentyl glycol (2,2-dimethyl-l,3- propanediol)] are used to refer to the polyesters prepared from these intermediates thus, T50I(NPG) is the copolyester from neopentyl glycol and equimolar amounts (50/50 molar ratio) of terephthalic and isophthalic acids. 

The hydroxyl containing polyester was synthesized from dimethyl terephthalate, isophthalic acidr trimellitic acidy and diethylene glycol or ethylene glycol using a butyl titanate catalyst. Ratios of reactants can be varied within limits to produce desired levels of hydroxyl content. 

The copolymers listed in Tables 1 and 2 comprise two series. In the first series (Table 1), a polysulfone oligomer of 6,000 g/mole was utilized. The sulfone-ester composition was held constant at 50-50 weight ratios while the composition of the polyester block itself was varied from 100% isophthalate to 100% terephthalate. At the extremes of composition (Samples I-l, 1-2, 1-7), the... 

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