Novel Macromolecular Architectures Based on Aliphatic Polyesters: Relevance of the “Coordination-Insertion” Ring-Opening Polymerization

Abstract

Recent developments in the macromolecular engineering of aliphatic polyesters have been overviewed. First, aluminum alkoxides mediated living ring opening polymerization (ROP) of cyclic (di)esters, i.e., lactones, lactides, glycolide, is introduced. An insight into this so-called "coordination-insertion" mechanism and the ability of this living polymerization process to prepare well-defined homopolymers, telechelic polymers, random and block copolymers is then discussed. In the second part, the combination of the living ROP of (di)lac-tones with other well-controlled polymerization mechanisms such as anionic, cationic, free radical, and metathesis polyadditions of unsaturated comonomers, as well as polyconden-sations, is reported with special emphasis on the design of new and well-tailored macromolecular architectures. As a result of the above synthetic breakthrough, a variety of novel materials have been developed with versatile applications in very different fields such as biomedical and microelectronics.

Synthesis and Characterization of PLA-Based Aliphatic-Aromatic Copolyesters: Effect of Diols

“…Dimethyl terephthalate (DMT) have been shown to increase the glass transition temperature (Tg) of PLA, a result from the incorporation of its stiffness of repeat structure to flexible PLA chain. (Mecerreyes, 1999) In this study, PLA-based aliphatic/aromatic copolyesters are prepared and their properties are characterized. The synthesis of these copolymers require 3 components; LA, DMT, and diols.…”

“…o C and melting point (T m ) is 130-230 o C (Mecerreyes, 1999). Figure 2.1 depicts the polymerization methods which are currently available for poly (lactic acid) (PLA) synthesis.…”

“…Alternatively, many researchers focus on ring-opening polymerization, which includes polycondensation of lactic acid, followed by a depolymerization into the dehydrated cyclic dimer, lactide, which can be ring-opening polymerized into high molar mass polymers. Tin(II)bis-2-ethylhexanoic acid or tin(II)octoate is preferred for the bulk polymerization of lactide at o C due to their solubility in molten lactide and high catalytic activity (Mecerreyes, 1999). (Mecerreyes, 1999) …”

“…Tin(II)bis-2-ethylhexanoic acid or tin(II)octoate is preferred for the bulk polymerization of lactide at o C due to their solubility in molten lactide and high catalytic activity (Mecerreyes, 1999). (Mecerreyes, 1999) …”

Hydrolases Part I: Enzyme Mechanism, Selectivity and Control in the Synthesis of Well-Defined Polymers

“…Well-defined (co)polyesters and polyester-based architectures can nowadays be accessed by a wide variety of organometallic [1][2][3][4] and organocatalytic [5] catalysts, and applications in advanced materials for biomedical applications and nanotechnology are foreseen in the near future [6,7]. Also, enzymes are perfectly equipped to convert monomers into polymers with high enantio-, regio-, and chemoselectivity [8,9].…”