Synthesis of spiro polymers,

Bailey, William J.; Volpe, A. A.

doi:10.1002/pol.1970.150080819

Cited by 26 publications

(26 citation statements)

References 13 publications

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“…A list of the synthesized polyurethanes is presented in Table 1. The ones prepared in bulk have often lower molecular weights (3)(4)(5)(6)(7)(8)(9)(10)(11), determined by SEC, as mechanical stirring stopped soon in the reaction process, limiting further build-up of the polymer chain. Even using EtOAc as solvent, higher molecular weights (8-45 kDa) could only be obtained by applying a mechanical stirrer.…”

Section: Polymer Synthesismentioning

confidence: 99%

“…Additionally, the mechanical strength of the corresponding polymers can be enhanced as a result of this rigidity. Among others, the synthetic approaches targeting spiropolymers, based on acetalization and analogous reactions, have been reported to be the most straightforward [1,3,4,[7][8][9][10][11][12][13][14]. However, the solubility in common organic solvents and the processability of the reported polymers were found to be very poor.…”

Section: Introductionmentioning

confidence: 96%

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Renewable thermoplastic polyurethanes containing rigid spiroacetal moieties

Lingier

Espeel

Suárez

et al. 2015

European Polymer Journal

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a b s t r a c tUnprecedented polyurethanes with rigid spiroacetal linkages in the backbone were synthesized from renewable resource compounds. First, the large-scale synthesis of a rigid diol monomer containing acetal bonds was established. Subsequently, this diol monomer was combined with seven different diisocyanates to vary the backbone of thermoplastic polyurethanes, leading to a spectrum of chemical and physical properties. The molar masses of the polymers ranged from 8 to 45 kDa and the corresponding polymers were obtained in high yields. DSC and DMTA analysis demonstrated glass transition temperatures up to 85°C. Acid-mediated degradation of the materials was not noticed during hydrolytic stability tests.

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Section: Polymer Synthesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Renewable thermoplastic polyurethanes containing rigid spiroacetal moieties

Lingier

Espeel

Suárez

et al. 2015

European Polymer Journal

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“…1,2 In particular, spiro-and other ladder-like polymers comprised of bicyclic repeat units wherein the rings connect through a common atom have received increasing attention due to their restricted rotational freedom and utility in forming thermally robust materials. 3,4 In some cases (e.g., the poly(spirobifluorene)s), the polycycles have been shown to adopt twisted helical structures that effectively prevented aggregation and enhanced their optical properties.…”

Section: ■ Introductionmentioning

confidence: 99%

Poly(2-imino-4-oxazolidinone)s via the Condensation of Diamidocarbenes with Bis(isocyanate)s

et al. 2015

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S Supporting Information ■ INTRODUCTIONPolycyclic polymers continue to attract interest as high performance materials on account of their high degrees of chemical and thermal stabilities. 1,2 In particular, spiro-and other ladder-like polymers comprised of bicyclic repeat units wherein the rings connect through a common atom have received increasing attention due to their restricted rotational freedom and utility in forming thermally robust materials. 3,4 In some cases (e.g., the poly(spirobifluorene)s), the polycycles have been shown to adopt twisted helical structures that effectively prevented aggregation and enhanced their optical properties. 5−12 Unfortunately, the synthesis of spiro-polycycles is challenging due to the need for an efficient polymerization reaction that forms cyclic linkages between the repeating units. 12 Toward this end, we recently demonstrated that readily available N,N′-diamidocarbenes (DACs) 13−15 rapidly and selectively afford 2-imino-4-oxazolidinones 16 upon exposure to 2 equiv of an isocyanate. The reactivity was remarkable as most NHCs catalyze the cyclotrimerization of isocyanates to isocyanurates rather than undergoing cycloaddition chemistry. 17 We envisioned condensing DACs with bifunctional isocyanates to access new classes of polycycles with functionally rich heterocyclic cores. Herein we report the synthesis and study of novel polyspiro(iminooxazolidinone)s via the formal [2 + 2 + 1] cycloaddition of a stable DAC with various diisocyanates. The chemistry presented herein overcomes many of the challenges associated with the synthesis of stable spirocenters in polymeric materials and provides a unique approach to rapidly access a new structural class of polyheterocycles. ■ RESULTS AND DISCUSSIONPreviously, we demonstrated that an oxazolidinone forms upon treatment of DAC 1 with two equivalents of 3-nitrophenylisocyanate. In order to use this chemistry to form high molecular weight polymers, we anticipated that less polarized and more solubilizing diisocyanates, such as methylene diphenyl diisocyanate (MDI), would be advantageous. Thus, initial experiments focused on probing the reactivity and product selectivity of 1 with phenylisocyanate, a nonpolymerizable model. As summarized in Scheme 1, adding two equivalents of phenylisocyanate to a solution of 1 in benzene resulted in the initial formation of a purple solution that became colorless after stirring for an additional 1 h at room temperature. The product of this reaction (2) was subsequently isolated in high yield (98%) as a white solid by recrystallization from benzene/pentane. Characterization using 1 H and 13 C NMR spectroscopy, high-resolution mass spectrometry, and elemental analysis supported the formation of a 2:1 isocyanate/DAC adduct. The structure of this product was unambiguously elucidated using single crystal X-ray diffraction (XRD) analysis (Figure 1, left), which confirmed the formation of the oxazolidinone heterocycle 2, rather than the isomeric hydantoin 3. 16 We postulated that the formation of 2 originate...

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“…Ketal formation between a cyclic diketone and a tetraol is a good illustration of such a reaction (1,2,3…”

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confidence: 99%

Synthesis of Polyspiroketals Containing Five-, Six-, Seven-, and Eight-Membered Rings

Bailey¹,

Beam²,

Cappuccilli³

et al. 1982

ACS Symposium Series

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Since the study of model compounds had shown that ketals containing five-, six-, seven-, and eight-membered rings could be formed in very high yields by heating a ketone or diketone with a diol in the presence of an acid catalyst with removal of the water that was formed by azeotropic distillation, these reactions were extended to produce a series of new analogous polyspiroketals. Furthermore since the formation of the intermediate hemiketal is not a stable product and it is necessary to proceed all the way to the ketal before a stable unit is formed, this reaction appeared ideal for the synthesis of soluble linear polyspiroketals containing only cyclicized structures. This reaction also represents a condensation polymerization analog of the free radical inter-intramolecular polymerization to produce linear polymers. Thus it was shown that linear soluble polymers could be prepared from the following polyfunctional materials: a five-membered ring -containing polyketal from 1,2,4,5-tetrahydroxy-cyclohexane and 1,4-cyclohexanedione; six-membered ring-containing polyketal from 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane, and 1,1,6,6-tetrakis(hydroxymethyl) cyclohexanone; six-membered ring-containing polyketal from 1,3-dihydroxyacetone, as well as 1,10-cyclooctadecanedione and pentaerythritol; a seven-membered ring -containing polyketal from 1,4-cyclohexanedione and 1,2,4,5-tetrakis(hydroxymethy1)-

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Synthesis of spiro polymers,

Cited by 26 publications

References 13 publications

Renewable thermoplastic polyurethanes containing rigid spiroacetal moieties

Renewable thermoplastic polyurethanes containing rigid spiroacetal moieties

Poly(2-imino-4-oxazolidinone)s via the Condensation of Diamidocarbenes with Bis(isocyanate)s

Synthesis of Polyspiroketals Containing Five-, Six-, Seven-, and Eight-Membered Rings

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