Synthesis of low molecular weight linear and branched polyesters based on 4,4′-isopropylidenediphenol and adipic acid

The synthesis and characterization of several low molecular weight polyesters based on 4,4′-isopropylidenediphenol (Bisphenol A) and adipic acid is described. These polyesters were prepared using a one-pot melt polymerization technique. Polymers of controlled variations of molecular weight, chain stiffness, and gel content were prepared. The chain stiffness was enhanced by adding increasing amounts of p-hydroxybenzoic acid (pHBA) to form a terpolymer, and gel content was attained by addition of the triol phloroglucinol. Using nonlinear step-reaction kinetics, the gel content was controlled. All polymers were characterized by NMR and infrared spectroscopy, thermogravimetry, differential scanning calorimetry, dilute solution viscometry, and gel permeation chromatography.