“Living” Cationic Polymerization of Phosphoranimines as an Ambient Temperature Route to Polyphosphazenes with Controlled Molecular Weights

Allcock, Harry R.; Crane, Chester A.; Morrissey, Christopher T.; Nelson, James M.; Reeves, Scott D.; Honeyman, Charles H.; Manners, Ian

doi:10.1021/ma960876j

Cited by 194 publications

(202 citation statements)

References 25 publications

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“…4. Synthesis of poly(dichlorophosphazene) from linear chlorophosphazene monomers, followed by chlorine replacement at the macromolecular level [28][29][30][31][32][33][34][35][36]. 5.…”

Section: Basic Polymer Synthesis Processesmentioning

confidence: 99%

Expanding Options in Polyphosphazene Biomedical Research

Allcock

2008

Polyphosphazenes for Biomedical Applications

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“…4. Synthesis of poly(dichlorophosphazene) from linear chlorophosphazene monomers, followed by chlorine replacement at the macromolecular level [28][29][30][31][32][33][34][35][36]. 5.…”

Section: Basic Polymer Synthesis Processesmentioning

confidence: 99%

Expanding Options in Polyphosphazene Biomedical Research

Allcock

2008

Polyphosphazenes for Biomedical Applications

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“…In a typical living cationic polymerization process, the monomer trichloro-(trimethylsilyl)-phosphoranimine (Cl 3 P=NSiMe 3 ) with PCl 5 as initiator Monomers such as Cl 3 P=NPOCl 2 and Cl 3 P=NPCl 2 were also used by some researchers with PCl 5 as catalyst in the presence of dichloromethane or noumenon to prepare PDCP via the living ionic polymerization process shown in Scheme 6 [21]. The average molecular weight is easily controlled by the molar ratio of monomer to catalyst (PCl 5 ) and the achievable polydispersities are lower than 2.…”

Section: Controllable Room Temperature Living Ionic Polycondensationmentioning

confidence: 99%

Progress in Synthesis of Polyphosphazenes

Ding

Wang

Yang

et al. 2008

Designed Monomers and Polymers

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Polyphosphazenes have unique compositions and structures, which impart these polymers with special chemical and physical properties and, therefore, make polyphosphazenes a promising class of future material for various applications. An enormous variety of polyphosphazenes has been synthesized in the last four decades and their applications range from biomedical to solid polymer electrolytes. In this paper the synthetic methods of polyphosphazenes are reviewed.  Koninklijke Brill NV, Leiden, 2008

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“…As shown in Figure 7, the molecular weights increased in proportion to conversion, while retaining narrow molecular weight distributions, and the ratios of both terminal groups is always 1.0. This ratio was easily estimated by 19 F NMR spectra, because the initiator bears the trifluoromethyl group, and the polymer end group is fluorine. The molecular weights also increased in proportion to the feed ratio of monomer 11a to initiator 12, and was in good agreement with the calculated values, although the polymers having higher molecular weights than 4000 were not soluble in the reaction solvent.…”

Section: Polymerizationmentioning

confidence: 99%

“…[15][16][17] However, condensation polymers with precisely controlled molecular weights and low polydispersities have not been obtained because of insolubility of polymers and of contamination of conventional step-growth polycondensation. The cationic polycondensation of phosphoranimines [18][19][20][21] and the polycondensation of dimethylsulfoxonium methylide initiated by trialkylboranes [22][23][24][25][26][27] yield well-defined polyphospahzenes and polymethylenes, respectively, but the structures of these propagating groups are different from the polymerizable groups of the monomers, and the monomers do not essentially react with each other.…”

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Chain-Growth Polycondensation: Living Polymerization Nature in Polycondensation and Approach to Condensation Polymer Architecture

Yokozawa

Yokoyama

2004

Polym J

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ABSTRACT:In this review article, polycondensation that proceeds in a chain-growth polymerization manner (''chain-growth polycondensation'') for well-defined condensation polymers are described. Our approach to chaingrowth polycondensation is (1) activation of polymer end group by substituent effects changed between monomer and polymer and (2) phase-transfer polymerization in biphase composed of monomer store phase and polymerization phase. In the approach (1), a variety of condensation polymers such as aromatic polyamides, aromatic polyesters, aromatic polyethers, poly(ether sulfone), and polythiophene with defined molecular weights and low polydispersities were obtained. Their polycondensations had all of the characteristics of living polymerization: a linear correlation between molecular weights and monomer conversion maintaining low polydispersities, and control over molecular weights by the feed ratio of monomer to initiator. Taking advantage of the nature of living polymerization in this polycondensation, we synthesized diblock copolymers of different kinds of aromatic polyamides and of aromatic polyamide and conventional polymers such as poly(ethylene glycol), polystyrene, and poly(tetrahydrofuran), as well as triblock copolymers and star polymers containing aromatic polyamide units. Some copolymers were arranged in a supramolecular self-assembly. In the approach (2), the polycondensation of solid monomer dispersed in organic solvent with a phase transfer catalyst (PTC) was carried out, where solid monomer did not react with each other, and the monomer transferred to organic solvent with PTC reacted with an initiator and the polymer end group selectively in organic solvent, to yield well-defined polyesters.KEY WORDS Chain-Growth Polycondensation / Polycondensation / Living Polymerization / Controlled Polymerization / Architecture / Polyamides / Polyesters / Polyethers / Polythiophenes / Polymerization can be classified into two categories: chain polymerization and step polymerization. Chain polymerization is initiated by the reaction of monomer and initiator, and then monomers react with the propagating group of polymers. If the chain polymerization proceeds in a living polymerization manner, the molecular weight of polymer is controlled by the feed ratio of monomer to initiator and the molecular weight distribution is narrow. In addition, the molecular weight increases in proportion to monomer conversion while retaining low polydispersity over the whole conversion range.On the other hand, step polymerization is initiated by the reaction of monomers with each other, and propagation involves the reactions of all kinds of oligomers with themselves, as well as the reactions of those oligomers with monomers. Therefore, it is difficult to control the molecular weight of polymer, and polymer possesses a broad molecular weight distribution. Plotting the molecular weight values and the polydispersity against monomer conversion, the molecular weight does not increase much in the initial and middle stage and is acce...

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“Living” Cationic Polymerization of Phosphoranimines as an Ambient Temperature Route to Polyphosphazenes with Controlled Molecular Weights

Cited by 194 publications

References 25 publications

Expanding Options in Polyphosphazene Biomedical Research

Expanding Options in Polyphosphazene Biomedical Research

Progress in Synthesis of Polyphosphazenes

Chain-Growth Polycondensation: Living Polymerization Nature in Polycondensation and Approach to Condensation Polymer Architecture

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