Trimethylene carbonate copolymerization

Dobrzynski, P., 2007. Mechanism of e-caprolactone polymerization and s-caprolactone/ trimethylene carbonate copolymerization carried out with Zr(Acac)4. Polymer 48, 2263-2279. 

Poly(glycolide-co trimethylene carbonate). Another successful approach to obtaining an absorbable polymer capable of producing flexible monofilaments has involved finding a new type of monomer for copolymerization with glycoHde (42). Trimethylene carbonate polymerized with glycoHde is shown below ... 

In order to achieve the desired fiber properties, the two monomers were copolymerized so the final product was a block copolymer of the ABA type, where A was pure polyglycoHde and B, a random copolymer of mostly poly (trimethylene carbonate). The selected composition was about 30—40% poly (trimethylene carbonate). This suture reportedly has exceUent flexibiHty and superior in vivo tensile strength retention compared to polyglycoHde. It has been absorbed without adverse reaction ia about seven months (43). MetaboHsm studies show that the route of excretion for the trimethylene carbonate moiety is somewhat different from the glycolate moiety. Most of the glycolate is excreted by urine whereas most of the carbonate is excreted by expired CO2 and uriae. 

These representative aliphatic polyesters are often used in copolymerized form in various combinations, for example, poly(lactide-co-glycolide) (PLGA) [66-68] and poly(lactide-co-caprolactone) [69-73], to improve degradation rates, mechanical properties, processability, and solubility by reducing crystallinity. Other monomers such as 1,4-dioxepan-5-one (DXO) [74—76], 1,4-dioxane-2-one [77], and trimethylene carbonate (TMC) [28] (Fig. 2) have also been used as comonomers to improve the hydrophobicity of the aliphatic polyesters as well as their degradability and mechanical properties. 

Fig. 3 Examples of monomer units having reactive side-chain groups, which can be copolymerized with polyesters (a) a-malic acid, (b) [S-malic acid, (c) a-carboxyl- -caprolactone, (d) carboxy lactic acid, (e) trimethylene carbonate derivative, and (1) depsipeptide...

Kinetic measurements of the ring-opening polymerization of trimethylene carbonate (TMC) versus the enchainment of oxetane and CO2 to provide poly (TMC) reveal that these processes in the presence of (salen)CrCl and an ammonium salt have similar free energies of activation (AG ) at 110°C. This similarity in reactivity coupled with the observation that in situ infrared studies of the copolymerization of oxetane and CO2 showed the presence of TMC during the early stages of the reaction has led to the overall mechanism for copolymer production shown in... 

Polyglyconate (5) is made by the bulk copolymerization of a mixture of 67% glycolide and 33% trimethylene carbonate. The suture is distributed under the trade names Maxon and Maxon CV. It is claimed to retain approximately 50% of its strength four weeks after implantation, 25% at six weeks, and to be essentially completely absorbed in six months. 

The ring-strain energy of oxetane is less than that of PO (106.7k] mol 1 versus llTZkJmoT1) hence, its copolymerization with C02 is less favored thermodynamically [3], Nevertheless, the copolymerization of oxetane and C02 occurs readily under similar catalytic conditions, producing poly(trimethylene carbonate),... 

Yttrium isopropoxide and yttrium 3-oxapentoxide initiators were the first lanthanide alkoxides described in the literature for the ROP of e-CL [93]. The discovery of lanthanide-based initiator systems allowed the block copolymerization of e-CL with compounds such as ethylene [94], tetrahydrofuran [95], L-LA [96], trimethylene carbonate [97], and methyl methacrylate [98]. This type of initiator has also been used to prepare poly((3-butyrolactone)s [99,100]. 

Aliphatic star-shaped polyesters of l-LA have been synthesized [114, 115] with multifunctional hydroxy compounds as initiators. The crystallinity of the star-shaped poly(L-LA) was found to be higher than that of the corresponding linear counterpart. Star-shaped poly(L-LA) has also been block copolymerized with trimethylene carbonate/e-CL [116] This resulted in a less brittle and considerably toughened material. 

Lanthanide-based initiator systems offer a fourth possibility, permitting the block copolymerization of lactones with compounds such as ethylene,tetrahy-drofuran, l-LA, trimethylene carbonate, and methyl methacrylate. Detrimental side reactions such as macrocyclic formation, transesterification, and racemiza-tion are absent and the reactions are extremely fast. 

Huang, Q. Shen, Z. Zhang, Y. Shen, Y. Shen, L. Yuan, H. Ring-opening copolymerization of trimethylene carbonate and D,L-lactide by rare earth chloride. Polym. J. 1998, 30 (3), 168-170. 

Matsumura, S. Tsukada, K. Toshima, K. Novel lipase-catalyzed ring-opening copolymerization of lactide and trimethylene carbonate forming poly(ester carbonate)s. Int. J. Biol. Macromol. 1999, 25 (1-3), 161-167. 

There has been a significant effort to copolymerize TMC with lactones and other carbonate monomers. Matsumura et al. performed copolymerizations of lactide with TMC using porcine pancreatic lipase at 100°C for 168h [113]. They obtained random copolymers with Mw values up to 21000. However, since trimethylene carbonate is known to thermally polymerize at 100 °C (see above), the extent of polymerization that occurs due to activation of monomers at the lipase catalytic triad versus by thermal or other chemical processes is not known [95], Lipase AK-catalyzed copolymerizations of l,3-dioxan-2-one (TMC) with 5-methyl-5-benzyloxycarbonyl-l,3-dioxan-2-one (MBC) were carried out in bulk at 80 °C for 72 h (Scheme 4.27). Although TMC reacted more rapidly than MBC, the product isolated at 72 h appeared to have a random repeat unit distribution [102], Similarly, using Novozym 435 in toluene at 70°C, TMC/PDL copolymerizations were performed and gave random copolymers. 

Furthermore, the ring-opening co-polymerization of BTMC with 5,5-dimethyl-trimethylene carbonate (DTC) by immobilized porcine pancreatic lipase (0.1 wt%) catalyzed in bulk copolymerization at 150°C for 24h [117]. Under these conditions, the highest molecular weight of poly(BTMC-co-DTC) of M =26 400 was obtained, with 83% monomer conversion. 

Kumar, A., Garg, K., and Gross, R.A. (2001) Copolymerizations of co-pentadecalactone and trimethylene carbonate by chemical and lipase catalysis. Macromolecules, 34 (11), 3527-3533. 

Copolymerization of lactides catalyzed by porcine pancreatic lipase (PPL) with cyclic trimethylene carbonate to give random copolymers with Mw up to 21 kgmoP1 and a PDI of 1.3-1.4 has been shown as well [19]. While CALB was shown to be... 

IPPL with different size were employed for ring-opening copolymerization of 5-benzyloxy-trimethylene carbonate (BTMC) with 5,5-dimethyl-trimethylene carbonate (DTC) in bulk (33). 

The amorphous polymeric, polyaxial initiators (PPIs) used in these systems to produce crystalline absorbable copolymeric materials can be made by reacting a cyclic monomer or a mixture of cyclic monomers such as trimethylene carbonate, caprolactone, and l,5-dioxapane-2-one in the presence of an organometallic catalyst with one or more polyhydroxy, polyamino, or hydroxyamino compounds having three or more reactive amines and/or hydroxyl groups. Typical examples of the latter compounds are glycerol and ethane-trimethylol, propane-trimethylol, pentaerythritol, triethanolamine, and N-2-aminoethyl-l,3-propanediamine. 

U. Edlund, A.C. Albertsson, Copolymerization and polymer blending of trimethylene carbonate and adipic anhydride for tailored drug dehvsy, J. Appl. Polymer Scd. 72 (1999) 227—239. 

PHA chemical modification can be done via block copolymerizadon and grafting reactions, chlorination, cross-linking, epoxidation, hydroxyl and carboxylic acid functionalization, etc. (Chen et al. 2009 Wu et al. 2008 Li et al. 2003 Loh et al. 2007). A common approach to confer toughness to PLA is the use of a flexible monomer or macromolecules for copolymerization with lactide to form PLA-based random or block copolymers. Reported PLA-based block copolymers include diblock, triblock, and multiblock copolymers, such as poly(L-lactic acid) (PLLA)-polycaprolactone (Jeon et al. 2003), poly(ethylene glycol)-PLLA (Chen et al. 2003), poly(trimethylene carbonate)-PLLA (Tohru et al. 2003), and PLA-PBS-PLA. 

Ling, J., Zhu, W., Shen, Z., 2004. ControUing ring-opening copolymerization of e-caprolactone with trimethylene carbonate hy scandium tris(2,6-di- tert -butyl-4-methylphenolate). Macromolecules 37 (3), 758—763. 

Al-Azemi, T.F., Harmon, J.P., Bisht, K.S., 2000. Enz3mie-catalyzed ring-opening copolymerization of 5-methyl-5-benzyloxycarbonyl-l,3-dioxan-2-one (MBC) with trimethylene carbonate (TMC) synthesis and characterization. Biomacromolecules 1, 493—500. 

Dobrzynski, P., Kasperczyk, J., 2006a. Synthesis of biodegradable copolymers with low-toxicity zirconium compounds. IV. Copolymerization of glycolide with trimethylene carbonate and 2,2-dimethyltrimethylene carbonate microstructure analysis of copolymer chains by high-resolution nuclear magnetic resonance spectroscopy. Journal of Polymer Science Part A Polymer Chemistry 44, 98—114. 

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