Synthesis and Thermal Behavior of Polyesters Derived from 1,3‐Propanediol and Various Aromatic Dicarboxylic Acids

Abstract

Seven aromatic dicarboxylic acids were esterified by melt polycondensation in two steps with 1,3‐propanediol (1,3‐PDO) in the presence of tetrabutoxytitanium as catalyst. The acids used were: terephthalic (TPA), isophthalic (IPA), naphthalene‐2,6‐dicarboxylic (2,6‐NDA), naphthalene‐1,4‐dicarboxylic (1,4‐NDA), biphenyl‐4,4^′‐dicarboxylic (4,4^′‐BPDA), diphenylsulfone‐4,4^′‐dicarboxylic (4,4^′‐DPSDA), and pyridine‐2,6‐dicarboxylic acid (2,6‐PDA). In the first step, the esterification reaction was monitored, by measuring the distilled water. The prepared oligomers were polycondensated in a second step under high vacuum using the same catalyst as before. The received poly(propylene dicarboxylate)s were characterized by viscometry, carboxyl end‐group content (CC), color measurement, and were studied by differential scanning calorimetry (DSC). From this study, the above polyesters could be classified to three classes: (a) easily crystallizing polyesters derived from TPA and 2,6‐PDA, (b) slow crystallizing polyesters derived from IPA and 2,6‐NDA, and (c) amorphous polyesters derived from 1,4‐NDA, 4,4^′‐BPDA, and 4,4^′‐DPSDA.

Keywords:

• 1,3‐Propanediol or 1,3‐propyleneglycol or 1,3‐trimethyleneglycol
• Dicarboxylic acid
• Poly(propylene dicarboxylate)s
• Differential scanning calorimetry
• PEN
• Crystallization
• Rigid amorphous phase

Acknowledgments

The authors would like to thank E. I. Du Pont de Nemours, Wilmington, DE and especially the department of Du Pont Sorona^TM Technology and Business Development for the supply of 1,3‐PDO and Amoco Chemicals‐Fine Acid (Chicago, IL) for providing the dimethyl naphthalene‐2,6‐dicarboxylate. Moreover, they would like to acknowledge Dr. Sophia Sotiropoulou and the Art Diagnosis Center (Ormylia Chalkidiki) for the color measurements of the polymeric samples.