Synthesis, thermal and radiation sensitivities of halogen-containing decamethylene-spacered aromatic polyesters

A series of halogen-containing aromatic polyesters with decamethylene-spacer groups was synthesized by the solution polymerization from 4,4′-dicarboxyl-1,10-diph-enoxy-decane and bisphenol A. Incorporation of fluorine atoms in the bisphenol A units in the polymer backbone enhanced the solubility of the polyesters in various organic solvents, as did the substitution of chlorine and bromine on the aromatic rings of the bisphenol A, ortho to the ester linkages. The effect of the halogen substituents on the thermal and radiation sensitivities of the polyesters has been investigated. The inherent viscosities of THF solutions at 3O°C ranged from 0.25 to 0.63 dL/g. The number average (6,000∼31,000) and weight average molecular weights (12,000∼48,000) were measured by gel permeation chromatogrpahy, resulting in polydispersity indices of M/M = 1.6∼2.O. The chemical structures of the polyesters were characterized by means of IR spectroscopy, H NMR and C NMR spectroscopies and elemental analyses. All the results were in good agreement with the expected formula. Comparison of C NMR spectra of the polymers aided in the assignments of the structures. Only the unsubstituted polyester derived from bisphenol A was found to be semicrystalline by X-ray diffraction and DSC measurements, with a crystalline melting temperature of 16O°C. The glass transition temperatures of the polyesters was found to be dependent on the size of the halogen substituent on the repeating units, and ranged from 77 to 14O°C. The thermal stabilities of the polyesters showed a dependence on the nature of the halogen substituent, as did the high energy radiation sensitivites of the polymers, as assessed by the yields of radicals at 77 K