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Synthetic polymers ring-opening polymerization

Biodegradable PHB with modified properties can be prepared synthetically, by ring-opening polymerization of butyrolactone. Under certain conditions a telechelic polymer may be prepared with oxytetramethylene groups in the main-chain. This polymer reacts with L-lactide in the presence of a catalyst with the formation of an A-B-A triblock copolymer, resulting in the formation of a biodegradable thermoplastic elastomer [42]. [Pg.306]

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. [Pg.267]

Ring opening polymerization produces a small number of synthetic commercial polymers. Probably the most important ring opening reaction is that of caprolactam for the production of nylon 6 ... [Pg.314]

In connection with studies on the ring-opening polymerization of cyclic acetals, we have undertaken investigations on the polymerization of bicyclic acetals, bicyclic oxalactone, and bicyclic oxalactam, which yield polysaccharide analogs, macrocyclic oligoesters, and a hydrophilic polyamide, respectively, some of which can be expected to be useful as novel speciality polymers. The monomers employed in the studies were prepared via synthetic routes presented in Scheme 1, starting from 3,4-dihydro-2H-pyran-2-carbaldehyde (acrolein dimer) I. [Pg.49]

Aldonolactones serve as suitable monomers for the generation of homo- and copolymers, especially through ring-opening polymerization (ROP). Among them are the carbohydrate-analogs of s-caprolactone, i.e., aldono-1,6-lactones. The first example of such derivatives and further ROP was reported by Galbis and co-workers [61], see also chapter, Synthetic polymers from readily available monosaccharides ... [Pg.30]

Although some interesting synthetic processes of cyclic polymers have been addressed, the cyclization principle can be classified into two main methods as indicated in Fig. 2. One is the utilization of the ring-chain equilibrium that occurs in many polycondensation and ring opening polymerization. Another is the end-to-end cyclization method that can be used for synthesizing cyclic polymers from a/o-difunclional linear precursors. The ring-closure reaction by the end-to-end cyclization is further divided into intermolecular reaction and intramolecular reaction, i.e., bimolecular process and unimolecular process, respectively. [Pg.124]

The aliphatic poly(ether lactonejs are a group of synthetic polymers with high elasticity and high tissue absorptivity [293]. The ether function in the polymer backbone adds flexibility to the ester chain. Ring-opening polymerization of l,4-dioxan-2-one yields an elastic polymer, polydioxanone, with a tensile strength similar to that of human tissue [294]. Polydioxanone has been successfully used to prepare monofilament sutures, with a flexibility superior to that of PGA sutures [294]. Recently, the lipase-catalyzed polymerization of polydioxanone was demonstrated [295]. [Pg.96]

Ring opening polymerization provides a synthetic method for introducing functional groups typical of condensation polymers into a polymer backbone, separated by varying lengths of methylenic units [Eq. (14)]. Typical functional groups include ethers, sulfides, esters, amides, double bonds, etc. [Pg.13]

For a synthetic polymer chemist the important question is whether the cyclization processes in cationic ring-opening polymerization can be controlled. If the preparation of linear polymer is attempted, then cyclic oligomers are undesirable side products. This is especially important in synthesis of telechelic polymers containing reactive end groups, because macrocycles would be unreactive admixtures. On the other hand, cyclic polymers, if prepared selectively, could be a valuable materials. [Pg.475]

This characteristic feature of cationic polymerization of THF allows the important synthetic application of this process for preparation of oli-godiols used in polyurethane technology and in manufacturing of block copolymers with polyesters and polyamides (cf., Section IV.A). On the other hand, the cationic polymerization of THF not affected by contribution of chain transfer to polymer is a suitable model system for studying the mechanism and kinetics of cationic ring-opening polymerization. [Pg.489]

S. Penczek, P. Kubisa, and K. Matyjaszewski, Cationic ring-opening polymerization—synthetic applications, Adv. Polym. Sci. 68/69 1 (1985). [Pg.542]

Synthetic PAs are produced by polycondensation of bifunctional monomers or by cationic and anionic ring-opening polymerization of lactams. Polymers obtained with the first technique are linear, whereas chain branching may occur with anionic polymerization. Based on their chemical structure, synthetic polyamides may be classified into two categories [1] ... [Pg.1218]

We report on the reaction of 2,2-dimethyl-1,3-propanediol catalyzed by various solid acids in the gas phase at temperatures > 250 °C. Originally, we tried to synthesize four membered cyclic ethers since several oxetanes are of synthetic interest [7,8], E g. 3-hydroxy-oxetane can undergo ring opening polymerization, leading to a water soluble polymer Since 3-hydroxy-oxetane is not very stable, we choose 2,2-dimethyl-1,3-propanediol as model substrate. In this communication, we describe the effect of catalyst structure (various zeolites. [Pg.595]


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