Lactones ring-opening copolymerizations

Scheme 4.20 Ring-opening copolymerization of lactone monomers.

Another interesting case is the ring-opening copolymerization of lactones (AA) and depsipeptides (AB), where the feed is made of AA and AB structures. At first glance, the copolymerization should lead to a random copolymer, but this is not the case, thematically, the reaction is ... 

In the lipase-catalyzed ring-opening copolymerization of cyclic monomers, the first example with lactones involved 5-VL and e-CL, using a lipase PF catalyst [98]. 

PHA copolymers were produced by fermentation of wild-type Aeromonas hydrophila (11) and a species of genetically modified Ralstotm eutropha. Additional samples of PHA copolymers were produced by chemical synthesis using the chiral ring opening copolymerization of [R]-P-lactones. The detailed procedure is described elsewhere (72). 

I. Ikeda, H. Horie, K. Suzuki, Synthesis of graft poly(ester ether) by ring-opening copolymerization of epoxy-terminated poly(ethylene glycol) with lactones. J. Appl. Polym. ScL, 51 (11) 1931-1935. 

Random poly(ester-amide)s by ring-opening copolymerization of lactams and lactones or from diols, diacids and diamide-diamine salts, (a) y = 5,11. 

Three 0-substituted B-lactones have been synthesized according to the now well established synthesis route using aspartic acid as chiral precursor . Three alcohols (benzyl, allyl and butyl) were used for the formation of the ester pendent group. Each malolactonic acid ester has been characterized by H and NMR spectra and IR. The synthesis of terpolymer PI has proceeded through anionic ring-opening copolymerization with benzoate tetraethylammonium as initiator (Scheme 1). 

The elucidation of the mechanism of ring-opening copolymerization of cyclic urea and carbonates offered opportunihes to study the general applicability of this mechanism to the copolymerizahon of tetramethylene urea with other monomers. The five-membered lactone, y-butyrolactone, is a readily available and cheap monomer, which may barely be homopolymerized (see Chapter 11). The copolymerization of tetramethylene urea with y-butyrolactone in the presence of dibutyl-magnesium as catalyst in the melt at 100 °C resulted in an alternating poly(amide urethane) (M = 12 600gmoT M = 21000gmoT = 1.67) [64]. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Sosnowski et al. [97, 98] have reported that uniform biodegradable polymeric particles with diameters of less than 5 pm can be prepared by ring-opening dispersion polymerization of L,L-lactide in heptane-dioxane mixed solvent in the presence of poly(dodecyl acrylate)- -poly( -caprolactone), which were synthesized by the copolymerization of dodecyl acrylate with the poly( -capro-lactone) macromonomers 21. Note that the polymer particles consist of well-defined poly(L,L-lactide) polymers with M -lxlO and... 

Polyesters contain the ester group —COO— in the main chain. Many methods are suitable for their synthesis self-condensation of a,o>-hydroxy acids, ring-opening polymerization of lactones, the polycondensation of dicarboxylic acids with diols, transesterification, the polycondensation of diacyl chlorides with diols, polymerization of O-carboxy anhydrides of a- and jS-hydroxycarboxylic acids, and the copolymerization of acid anhydrides with cyclic ethers. The last reaction is commercially used in the curing of epoxides with anhydrides. 

Although the assays of homopolymerization of this lactone were also unsuccessful, we carried out a copolymerization experiment by the bulk ring-opening polymerization of a mixture of L-lactide and 2,3,4,5-tetra-O-methyl-D-glucono-1,6-lactone, in a ratio of 5 1, using tin (IT) 2-ethyUiexanoate (SnOct2) as initiator. From the copolymerization reaction mixture, we obtained two copolymers, containing 1.3 and 2.2 per cent of the carbohydrate monomer, respectively, as determined by NMR studies. 

Nishiura, M., et al., 1999. Ring-opening polymerization and copolymerization of lactones by samarium(n) aryloxide complexes. Macromolecules 32 (25), 8245—8251. 

Lactones. Esters cycZo-(CH2)nC02 (ra = 4, 5) have been shown by Yamashita and co-workers to be efficiently polymerized by the lanthanocenes (C5(CH3)5)2Sm((CH3))(THF) and [Cp2Yb(CH3)]2 (229). Recent work of Evans and co-workers has revealed that the highly reactive, divalent pentamethyl-samarocene, optionally solvated by THE, which can effectively polymerize -caprolactone by ring-opening (230), also copolymerizes ethylene carbonate and -caprolactone (eq. 33) (231). Even when present at levels up to 23 mol% in the copolymer, the carbonate imits appear to be isolated, indicating a low level of blockiness. 

Random polymers are the statistical arrangement of comonomer in their backbone. Numerous monomers have been used to copolymerize with LA, such as lactones, cyclic carbonates, hydroxyl acid, amino acid, and so on, to improve the flexibility, thermal stability, degradability, biocompatibility, hydrophilicity, functionality, etc. The most widely used technique to synthesize random copolymers of PLA is controlled/ living ring-opening polymerization. 

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