Reactivity ratios for the anionic copolymerization of ethylene oxide and butylene oxide in bulk

Dickson, Stewart; Yu, Ga-Er; Heatley, Frank; Booth, Colin

doi:10.1016/0014-3057(93)90094-v

Cited by 11 publications

(9 citation statements)

References 7 publications

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“…For the bulk polymerization of EO and BO in the absence of crown ethers and at temperatures of 40 and 60 °C the reactivity ratios r E = 4.1 and r B = 0.17 were found. 29 This comparison also indicates that the anionic polymerization kinetics of the EO/BO system is rather robust against the reaction conditions. In comparison, for the system EO and propylene oxide the difference of the reactivity ratios is less pronounced.…”

Section: ■ Results and Discussionmentioning

confidence: 79%

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Determination of the Compositional Profile for Tapered Copolymers of Ethylene Oxide and 1,2-Butylene Oxide by In-situ-NMR

et al. 2013

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In this work, 1 H NMR was used to examine the anionic copolymerization kinetics of ethylene oxide and 1,2butylene oxide. The in situ NMR technique allows monitoring the concentration profiles of both monomers simultaneously. A series of polymerization experiments at different monomer and initiator concentrations were done in order to determine the copolymerization rate constants. The data were evaluated by fitting the result of a numerical solution of the kinetic differential equations to the NMR data. This procedure allowed calculating all four rate constants, k EE , k EB , k BE , and k BB , individually instead of the commonly determined reactivity ratios r E = k EE /k EB and r B = k BB /k BE . The monomer incorporation into the copolymer chains is dominated by the different reactivities of the monomers, whereas the nature of the chain ends is of minor importance. In the system investigated ethylene oxide is about 6.5 times more reactive than 1,2butylene oxide. The compositional profiles of the final copolymers can be calculated from the time-resolved concentration profiles. If both monomers are present at the start of the polymerization the compositional profiles have a sigmoidal shape with one chain end containing mainly ethylene oxide and the other chain end being formed almost exclusively of butylene oxide units. However, with the knowledge of the copolymerization rate constants it is possible to realize other compositional profiles. If the reactor is first charged with ethylene oxide the addition rates of butylene oxide can be calculated in order to obtain any other arbitrarily chosen compositional profile.

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Section: ■ Results and Discussionmentioning

confidence: 79%

“…In comparison, for the system EO and propylene oxide the difference of the reactivity ratios is less pronounced. 29 In the case of EO and glycidyl ethers r E is even smaller than the reactivity ratio of the glycidyl ether. 30 However, in all these cases the copolymerization behaves approximately ideal.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Determination of the Compositional Profile for Tapered Copolymers of Ethylene Oxide and 1,2-Butylene Oxide by In-situ-NMR

et al. 2013

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“…The LCST of a statistical copolymer of EO and propylene oxide (PO) depends upon the proportion of the two monomers, and thus can be tuned from temperatures below ambient (at high PO content) to near the boiling point of water (at high EO content). Although controlled anionic statistical polymerization of EO and PO or EO and butylene oxide has been reported,34, 35 we have opted to initially study two commercially available copolymer compositions: dihydroxy‐capped copolymer, HO‐(PEO‐ stat ‐PPO)‐OH, with 75 wt % EO and reported M n of 12,000 g/mol and monobutyl‐monohydroxy capped copolymer, BuO‐(PEO‐ stat ‐PPO)‐OH, with 50 wt % EO and M n values of 1230 g/mol (UCON 50‐HB‐400), 2660 g/mol (UCON 50‐HB‐2000), and 3930 g/mol (UCON 50‐HB‐5100). We confirmed that these commercially available materials have random, not blocky, distributions of the two monomers by comparison of their 13 C NMR spectra to previously reported fully assigned spectra for the random copolymers 36…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of thermoresponsive amphiphilic block copolymers incorporating a poly(ethylene oxide‐stat‐propylene oxide) block

Aubrecht

Grubbs

2005

J. Polym. Sci. A Polym. Chem.

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Amphiphilic BuO-(PEO-stat-PPO)-block-PLA-OH diblock and MeO-PEOblock-(PEO-stat-PPO)-block-PLA-OH triblock copolymers incorporating thermoresponsive poly(ethylene oxide-stat-propylene oxide) (PEO-stat-PPO) blocks were prepared by ring-opening polymerization of lactide (LA) initiated by macroinitiators formed from treating BuO-(PEO-stat-PPO)-OH and MeO-PEO-block-(PEO-stat-PPO)-OH with AlEt 3 . MeO-PEO-block-(PEO-stat-PPO)-OH was prepared by coupling MeO-PEO-OH and HO-(PEO-stat-PPO)-OH, followed by chromatographic purification. The cloud points of 0.2% aqueous solutions are between 36 and 46 8C for the diblock copolymers that contain a 50 wt % EO thermoresponsive block and 78 8C for the triblock copolymer that contains a 75 wt % EO thermoresponsive block. Variable temperature 1 H NMR spectra recorded on D 2 O solutions of the diblock copolymers display no PLA resonances below the cloud point and fairly sharp PLA resonances above the cloud point, suggesting that desolvation of the thermoresponsive block increases the miscibility of the two blocks. Preliminary characterization of the micelles formed in aqueous solutions of BuO-(PEO-stat-PPO)-block-PLA-OH conducted using laser scanning confocal microscopy and pulsed gradient spin echo NMR point to significant changes in the size of the micellar aggregates as a function of temperature. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5156-5167, 2005

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“…Polymerizations were performed in bulk, using alcohol- potassium alkoxide mixtures as initiators, resulting in narrow molecular weight distributions. In general, rather short PBO blocks were synthesized. − Several groups extensively explored the materials properties of the copolymers, focusing on the dependence of micellization and gelation behavior on the block architecture. − Following the trend in hydrophobicity, copolymers of EO and BO exhibit lower critical micelle concentrations than copolymers of EO with PO, even if the hydrophobic block is shorter (Figure ). In this context one may emphasize that low molecular weight PPO homopolymers are water-soluble below a critical solution temperature. , …”

Section: Poly(alkylene Oxide) Structures: Innovative Polyether Struct...mentioning

confidence: 99%

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

et al. 2015

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The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex branched, hyperbranched, and dendrimer like polyethers. Amphiphilic block copolymers based on PEO and PPO (Poloxamers and Pluronics) and advances in the area of PEGylation as the most important bioconjugation strategy are also summarized. With the ever growing toolbox for epoxide polymerization, a "polyether universe" may be envisaged that in its structural diversity parallels the immense variety of structural options available for polymers based on vinyl monomers with a purely carbon-based backbone.

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Reactivity ratios for the anionic copolymerization of ethylene oxide and butylene oxide in bulk

Cited by 11 publications

References 7 publications

Determination of the Compositional Profile for Tapered Copolymers of Ethylene Oxide and 1,2-Butylene Oxide by In-situ-NMR

Determination of the Compositional Profile for Tapered Copolymers of Ethylene Oxide and 1,2-Butylene Oxide by In-situ-NMR

Synthesis and characterization of thermoresponsive amphiphilic block copolymers incorporating a poly(ethylene oxide‐stat‐propylene oxide) block

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation

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