Syntheses of High Molecular Weight Poly(l-phenyllactic acid)s by a Direct Polycondensation in the Presence of Stable Lewis Acids

Abstract

Poly(l-phenyllactic acid)s (PlPhLAs) with high molecular weight were prepared by a direct polycondensation of l-phenyllactic acid in the presence of stable Lewis acids such as HfCl4·2THF under various reaction conditions. As a result, PlPhLAs with a number-average molecular weight (Mn) more than 100000 g mol−1 were obtained and showed specific optical rotation [α ]D25 of −46° and the glass-transition temperature (Tg) of 55 °C whose absolute values were higher than the reported values and was comparable with Tg of poly(l-lactic acid).

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

“…As previously reported, a polyester (that is, poly(D-phenyl-β-lactic acid)), whose monomer is a lactic acid derivative with a phenyl ring as a bulky side chain, was prepared to increase the T g values of polylactate-derived polyester. 6,7 However, the T g of the polyesters were unexpectedly as high as that of the conventional poly(lactic acid) (PLA), indicating that the phenyl side group does not increase the T g .…”

“…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.…”

Enantioselective Biosynthesis of l-Phenyllactic Acid by Whole Cells of Recombinant Escherichia coli

“…As a result of a chiral carbon atom in its molecule, PLA occurs as two enantiomers, l -3-phenyllactic acid ( l -PLA) and d -3-phenyllactic acid ( d -PLA), both of which are valuable chiral building blocks but have different biological functions, leading to their various applications in the pharmaceutical and chemical industries [ 11 ]. d- PLA is applied in the synthesis of hypoglycemic drugs and high-efficiency and low-toxicity anthelmintics, while l -PLA is an important precursor for the synthesis of the non-protein amino acid statine, anti-HIV drugs, and biodegradable poly(PLA), clearly indicating that the optical purity of stereoisomeric monomers plays a very important role in their applications [ 3 , 12 , 13 , 14 ]. Especially for food and pharmaceutical purposes, chiral monomers with high optical purity and low impurity levels are a prerequisite to avoid toxicosis and isomeric ballast [ 15 ].…”

Production of optically pure l-phenyllactic acid by using engineered Escherichia coli coexpressing l-lactate dehydrogenase and formate dehydrogenase

“…Both l-and d-enantiomers can be used as antiseptic agent with broadspectrum antimicrobial activity and as feed additive to replace antibiotics in livestock feeds (Dieuleveux et al, 1998;Lavermicocca et al, 2003;Schnürer and Magnusson, 2005;Wang et al, 2009a,b). Recently, highly optically pure PLA has been extended to synthesis of poly(phenyllactic acid)s, a potential alternative of poly(lactic acid)s (Nguyen et al, 2011;Fujita et al, 2013). As a biodegradable and biocompatible polyester, poly(l-lactic acid)s has been applied in plastics, pharmaceutics, and agrochemistry, but its inherent characteristics of poor hydrophobicity and brittleness have limited its application ranges.…”

“…As a biodegradable and biocompatible polyester, poly(l-lactic acid)s has been applied in plastics, pharmaceutics, and agrochemistry, but its inherent characteristics of poor hydrophobicity and brittleness have limited its application ranges. Instead, poly(l-phenyllactic acid)s, which incorporate a bulk aromatic group at C-3 group of l-lactic acid, can overcome those problems (Nguyen et al, 2011;Fujita et al, 2013).…”