Ring opening polymerization lactide

L-lactide ring opening polymerization CORI Kinetics model based on Ludovic using axial dispersion and compartment model (series of ideal perfectly mixed and plug flow) Banu et al. 2010... 

A1 (8.103) and Zn (8.104 and 8.105) complexes are efficient initiators for l-LACTIDE ring-opening polymerization in the presence of benzyl alcohol, and polymerization reactions take place in an immortal manner, that is, their polydisper-sity index (PDI) is almost 1 (PDI=1.02,MW= 13,000-14,000) [147].Bis(phosphino) carbazole (PNP-carbazolide) rare-earth metal bis(alkyl) complexes (8.106) initiated... 

Schwach, G Coudane, J. Engel, R. Vert, M. Zn lactate as initiator of DL-lactide ring opening polymerization and comparison with Sn octoate. Polym. Bull. 1996, 37, 771-776. 

Scheme 8.2 Comprehensive kinetic scheme of lactide ring-opening polymerization.

One biopolymer that is already used as a matrix for composite production is poly(lactic acid) (PLA). The PLA is a thermoplastic biopolymer with lactic acid which is derived from starch by a fermentation process as its basic monomer. High molecular weight PLA is polymerized by the lactide ring opening polymerization to PLA (Garlotta, 2001 Gupta et al., 2007 Lim et al., 2008). 

Currently, NatureWorks is largest producer of PLA for domestic applications. NatureWorks employs lactide ring-opening polymerization for the mass production of 140,000 MT per year of PLA, which is branded as Ingeo . NatureWorks PLA is produced mainly for biodegradable packaging, containers, clothing, fibers, etc. Purac is the major producer of PLA for the biomedical and pharmaceutical industries. 

In contrast to the more traditional polycondensation, lactide ring opening polymerization provides a direct and easy access to the corresponding high molecular weight polylactide. Thus lactic acid can be transformed into lactides, by means of a combined process of oligomerization and cyclization. The racemic mixture of L and D lactic acid generate three different types of lactides two optically active forms and a mesoform. 

Braided Synthetic Absorbable Sutures. Suture manufacturers have searched for many years to find a synthetic alternative to surgical gut. The first successful attempt to make a synthetic absorbable suture was the invention of polylactic acid [26023-30-3] suture (15). The polymer was made by the ring-opening polymerization of L-lactide [95-96-5] (1), the cycUc dimer of L-lactic acid. 

The preparation of PGA given below (Scheme 2.51) is a polycondensation of glycolic acid followed by a solid-state postpolycondensation.374 (Reproduced from ref. 374. Copyright 2000 Elsevier Science Ltd, by permission of the copyright owner.) This method is different from the commonly used ring-opening polymerization of lactide (see Section 2.3.6). 

Recently, Cohn and Salomon synthesized and characterized a series of PLCL thermoplastic bioelastomers by two-step synthesis procedure. First, ring-opening polymerization of L-lactide initiated by the hydroxyl terminal groups of the PCL chain. Second, chain extension polymerization of these PLA-PCL-PLA triblocks initiated by the hexamethylene diisocyanate (HDl). 

Dittrich, V. W., and Schulz, R. C., Kinetics and mechanism of the ring-opening polymerization of L-lactide, Angew. Makro-mol. Chem.. 15. 109, 1971. 

Figure 13.1.4 The synthesis of poly(lactic acid) (PLA) by a ring-opening polymerization of the cyclic diester of lactic acid (lactide).

Polyester syntheses have been achieved by enzymatic ring-opening polymerization of lactide and lactones with various ring-sizes. Here, we focus not only on these cyclic esters but also other cyclic monomers for lipase-catalyzed ringopening polymerizations. Figure 8 summarizes cyclic monomers for providing polyesters via lipase catalysis. 

By using a combination of RAFT and ring opening polymerization (ROP), (polyethylene oxide) methyl ether)(polystyrene)(poly(L-lactide) 3-miktoarm star terpolymers have been successfully synthesized [182]. The synthetic approach involved the reaction of the cw-functionalized - OH group of the poly(ethylene oxide) methyl ether with maleic anhydride under conditions where only one hydroxyl group can be esterified (MPEO). The double bond... 

Table 2 Ring-opening polymerization of lactones initiated by lanthanide complexes (CL = e-caprolactone LA = lactide TMC = trimethylene carbonate). 

Chisholm et al. synthesized organozinc compounds with bulky biphenolates as catalysts for the ring-opening polymerization of lactides.196 The protonolysis of diethyzinc by the biphenols, in the presence of diisopropylmethanol, afforded the polycyclic, trimetallic zinc-di(ethylzinc) pre-catalyst 135, which polymerizes /m -lactide to polylactide, enriched in isi- and. sir-tetrads (Scheme 85). 

DIAMETER AND DIAMETER DISTRIBUTIONS OF POLY(l-LACTIDE) MICROSPHERES BY RING-OPENING POLYMERIZATION OF l-LACTIDE AND FROM EARLIER SYNTHESIZED POLYMERS... 

Diameter and Diameter Distributions of Poly(L-lactide) Microspheres by Ring-Opening Polymerization of L-Lactide and from Earlier Synthesized Polymers... 

Over the years we have developed methods for the direct synthesis of hydrolytically and/or enzymatically degradable microspheres by ring-opening polymerization of e-caprolactone and lactides [6-12]. The diameters of these microspheres are usually less than 3 xm. In this chapter we discuss... 

Surface-initiated ring-opening polymerization of e-caprolactone on pCP SAM initiators equipped with an oligo-ethylenoxide function is reported by Hawker et al. [346]. Choi and hanger used a similar SAM initiator system to polymerize L-lactide [347]. 

Aluminum Alkoxides Mediated Ring Opening Polymerization of Lactones and Lactides... 

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