New Polymer Syntheses. 80. Linear, Star-Shaped, and Hyperbranched Poly(Ester-Amide)s from Silicon-Mediated One-Pot Condensations of 3-Acetoxy-, 3,5-Bisacetoxybenzoic Acid, and 3-Aminobenzoic Acid

Abstract

Acylation of N,O-bistrimethylsilyl-3-aminobenzoic acid with 3-acetoxybenzoylchloride yielded the trimethylsilylester of N-(3′-acetoxybenzoyl)-3-aminobenzoic acid, which was polycondensed in situ at 260 or 280°C. Cocondensation with acetylated tetraphenols yielded four-arm star copolymers with a random or preferentially alternating sequence of 3-hydroxy and 3-aminobenzoyl units. Due to ester-amide exchange detected by ¹H- and ¹³C-NMR spectroscopy, the sequences were never perfectly alternating. Methyl groups attached to the star centers allowed the determination of degrees of polymerization by ¹H-NMR spectroscopy. Acylation of N,O-bistrimethylsilyl-3-amino benzoic acid with 3,5-bisacetoxybenzoylchloride yielded a trifunctional monomer, the polycondensation of which yielded a hyperbranched poly(ester-amide). By cocondensation of the trifunctional monomer with acetylated tetraphenyl, star-shaped poly(ester-amide)s with four hyperbranched star arms were obtained. All these poly(ester-amide)s are amorphous materials with glass-transition temperatures in the 190–200°C range and good solubility in polar organic solvents.