Poly(phenyllactide):  Synthesis, Characterization, and Hydrolytic Degradation

Abstract

Poly(phenyllactide) was synthesized via the ring-opening polymerization of phenyllactide, the dimer of phenyllactic acid. Phenyllactide was synthesized by two methods, the solution phase condensation of L-phenyllactic acid and by thermal cracking of low molecular weight phenyllactic acid oligomers. The poor solubility of the monomer limited solution polymerizations of phenyllactide to low yields and low molecular weights, but melt polymerization of phenyllactide with Sn(Oct)2/tert-butylbenzyl alcohol at 180 degrees C gave high molecular weight polymers in high yields. The resulting polymers were amorphous due to epimerization of approximately 10% of the stereocenters during polymerization. Poly(phenyllactide) has a glass transition temperature of 50 degrees C and degrades to monomer at 320 degrees C. Experiments run at 55 degrees C at pH 7.4 show that poly(phenyllactide) degrades at approximately 1/5 the rate of rac-polylactide.

Glass Transitions in Polylactides

“…The requisite benzyl glycolide was easily prepared by acid-catalyzed cyclization of the corresponding a-hydroxyacid, and its polymerization proceeded with good control over the polymer architecture. 66 Despite the addition of a bulky aromatic ring and the potential for p-p interactions in the polymer, the T g for high molecular weight polymer was only 508C, comparable to poly(isopropyl glycolide), but significantly higher than poly(isobutyl glycolide), its closest structural analogue among the poly(alkyl glycolide)s. Obviously the steric effects of aromatic rings decrease as they are moved farther from the polymer backbone, paralleling the results seen for poly(isopropyl glycolide) and poly(isobutyl glycolide). We also briefly investigated the addition of methyl groups to the aromatic rings-these were shown to increase the T g of polystyrenes.…”

Fermentation of aromatic lactate monomer and its polymerization to produce highly thermoresistant bioplastics

“…4,12,17 In addition, this value surpassed those of other lactide-derived polyesters, such as PLAs and poly(phenyllactic acid)s (450°C). 6,7,15,18 The T g value indicates that PDHPA-TP possesses significantly improved thermoresistance. The benzene components of DHPA strongly contributed to the rigidity of the bio-based PDHPA-IP and PDHPA-TP.…”

New Biocompatible Polyesters Derived from α-Amino Acids: Hydrolytic Degradation Behavior

“…The hydroxy acids were polymerized by direct condensation [31,32]. In a typical experiment, 6.4-11.1 mmol (~1 g) of the hydroxy acid was suspended in toluene (3 mL) and 1% w/w (1 mg) of p-toluene sulfonic acid as catalyst was added.…”