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Ring-opening polymerizations materials

In contrast to this, 1,2-dimethylcyclopropene solely yields ring-opened, polymeric material on reaction with [(C3H5)PdCl]2. ... [Pg.222]

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... [Pg.597]

As early as 1895, the synthesis of polydichlorophosphazene was attempted by H.N. Stokes by thermal ring-opening polymerization of hexachloro-triphosphazene [(NPCl2)3]. The product obtained by H.N. Stokes was a high-molecular weight cross-linked rubbery material called inorganic rubber which is insoluble in all solvents and hydrolytically decomposes into phosphates, ammonia, and hydrochloric acid in the presence of moisture. Because of its insolubility and hydrolytic instability, the polymer found no technological application and remained as a laboratory curiosity. [Pg.239]

At the same time, ring-opening-polymerization (ROP) processes, which dominated the phosphazene field for decades [38], tend now to be substituted by polycondensation reactions. These seem to be more feasible and reproducible, easier to carry out, and able to guarantee predictable MWs and MW distributions for these materials [10]. [Pg.168]

Work on phosphazene high polymers continues to attract increased interest. Advances in the study of the ring-opening polymerization, and physical characterization in the solid state, of the materials produced by these reactions have been reported. [Pg.460]

Chojnowski, J. Cypryk, M. Fortuniak, W. Kazmierski, K. Rozga-Wijas, K. Scibiorek, M. Controlled Synthesis of All Siloxane Architectures by Ring-Opening Polymerization. In Synthesis and Properties of Silicones and Silicone-Modified Materials Clarson, S. J., Fitzgerald, J. J., Owen, M. J., Smith, S. D., Van Dyke, M. E., Eds. AGS Symposium Series 838 American Chemical Society Washington, DC, 2003 pp 12-25. [Pg.687]

Cypryk, M. Chojnowski, J. Kurjata, J. Tertiary Trisilyloxonium Ion and Silylenium Cation in Cationic Ring-opening Polymerization of Cyclic Siloxanes. In Organosilicon Chemistry VI From Molecules to Materials Auner, N., Weis, J., Eds. Wiley-VCH Weinheim, 2005 pp 85-92. [Pg.687]

Synthesis of aminopolysaccharides, therefore, is one of the important research areas in the field of functional materials, examples of biorelated polymers, antibacterial substance, and biodegradable polymers as well as materials for drugs and matrices of drug delivery systems. Only a few methods, however, such as ring-opening polymerization and enzymatic polymerization have been available for the precision synthesis of aminopolysaccharides [4,5],... [Pg.256]

Materials. PCL and polypropiolactone (PPL) were prepared by ring opening polymerization of e -caprolactone ( ) and S -propiolactone respectively in benzene in a nitrogen atmosphere at 60 C with a di-... [Pg.136]

The biodegradable polymer available in the market today in largest amounts is PEA. PEA is a melt-processible thermoplastic polymer based completely on renewable resources. The manufacture of PEA includes one fermentation step followed by several chemical transformations. The typical annually renewable raw material source is com starch, which is broken down to unrefined dextrose. This sugar is then subjected to a fermentative transformation to lactic acid (LA). Direct polycondensation of LA is possible, but usually LA is first chemically converted to lactide, a cyclic dimer of LA, via a PLA prepolymer. Finally, after purification, lactide is subjected to a ring-opening polymerization to yield PLA [13-17]. [Pg.110]

Previously, PLAs were obtained via condensation of lactic acid by heating and driving off water, which produced a gummy polymeric material of ill-dehned molecular weight and microstmcture [6]. Ring-opening polymerization (ROP) of dilactones, pioneered by Carothers in 1932 [7], was the hrst initiative for an... [Pg.221]


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See also in sourсe #XX -- [ Pg.2 ]




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