Novel and Simple Synthesis of Carboxyl-Terminated Polyisobutylenes

Nagy, Miklós; Kéki, Sándor; Orosz, László; Deák, György; Herczegh, Pál; Levai, A.; Zsuga, Miklós

doi:10.1021/ma050075t

Cited by 12 publications

(8 citation statements)

References 15 publications

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“…However, mass spectrometric analysis of highly nonpolar isobutylene with a fully saturated structure by MALDI and/or ESI fails due to the lack of appropriate ionization sites. It has also been shown that the introduction of aromatic moieties (e.g., using aromatic initiators for the isobutylene polymerization) and/or polar or readily ionizable groups into the polyisobutylene facilitates the ionization under MALDI and ESI conditions [12][13][14][15][16][17]. It is therefore evident that nonpolar polymers like polyisobutylenes are not amenable to MS analysis due to the lack of effective site for ionization.…”

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confidence: 99%

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Nagy

Pálfi

Narmandakh

et al. 2009

J. Am. Soc. Mass Spectrom.

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Nine polyisobutylene (PIB) derivatives with different end groups (chlorine, vinyl, isobutenyl, 2,2-diphenylvinyl, and carboxyl) and molecular weights (1000 to 4500 g/mol), initiated by monofunctional and aromatic bifunctional initiators were studied by atmospheric pressure photoionization mass spectrometry (APPI-MS) in both negative and positive ion modes. Consistent with previous findings, negative ion APPI-MS revealed end-group identities through the formation of PIB adducts with chloride ions formed in situ from a chlorinated solvent (e.g., CCl 4 ) in the presence of a dopant (toluene). In positive ion mode, considerable fragmentation of these PIB derivatives was observed, rendering end-group determinations very difficult. The M n values obtained by APPI(Ϫ)-MS were considerably lower than those determined by SEC for PIB derivatives with M n higher than 2000 g/mol. PIBs containing carboxyl termini can undergo collision-induced dissociation, yielding structurally important product ions. The resulting APPI-MS/MS intensities were found to reflect the "arm-length" distribution for PIBs with bifunctional aromatic moieties. In positive ion mode, [M ϩ COCl]

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confidence: 99%

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Nagy

Pálfi

Narmandakh

et al. 2009

J. Am. Soc. Mass Spectrom.

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“…Mass spectrometric analysis of other industrially important nonpolar polymers, especially those composed of saturated, nonpolar moieties, e.g., polyisobutylenes, usually fails due to the lack of effective sites for ionization. Recently, we have shown that MALDI-spectra of good quality can be obtained by introducing aromatic moieties (e.g., using aromatic initiators for initiation of the isobutylene polymerization) and/or polar groups into the polyisobutylene chain [15][16][17][18]. Good spectral quality in the negative ion mode under MALDI conditions can also be attained by modifying the olefin end-groups of polyisobutylene to ϪSO 3 H [19].…”

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confidence: 99%

Atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives

Kéki

Török

Nagy

et al. 2008

J. Am. Soc. Mass Spectrom.

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Atmospheric pressure photoionization mass spectrometric (APPI-MS) study on three types of polyisobutylene derivatives is reported. Two of the polyisobutylenes investigated were polyisobutylene with dihydroxy and diolefinic end-groups derived from aromatic moieties [dicumyl chloride, 1,4-bis(2-chloro-2-propyl)benzene], and the third contained no aromatic moieties with a monohydroxy end-group. All three polyisobutylene derivatives (PIBs) had an average molecular weight (M n ) of ϳ2000 g/mol, with a polydispersity lower than 1.2. In the positive ion APPI mode, protonated PIB molecules were formed, but the molecular weights obtained were considerably lower than those expected, indicating fragmentation of the PIB chains. In the negative APPI mode, using solvents such as tetrahydrofuran and toluene as dopants, no signal was obtained. However, in chlorinated solvents, such as CCl 4 , CHCl 3 , and CH 2 Cl 2 , in the presence of toluene dopant, PIB adducts with chloride ions were formed with relatively high signal intensity. In the case of CH 2 Cl 2 , no dopant (toluene) was necessary to generate chlorinated adduct ions, albeit increasing the toluene concentration in the flow increased the PIB signal intensity. The effect of the toluene concentration on PIB signal intensity was studied and models that include (1) photoionization of toluene, (2) formation of chloride ions from the chlorinated solvents by dissociative electron capture, (3) formation of chlorinated adduct ions and charge recombination reactions between the toluene radical cation, (4) chloride ions, and (5) olymer characterization, including the determination of molar mass, molar mass distribution, the mass of the repeat unit and end-groups, and functionality, is an important process that can be accomplished using several methods. Mass spectrometric methods, particularly those that utilize soft-ionization techniques, e.g., matrix-assisted laser desorption/ionization (MALDI) [1,2] or electrospray ionization (ESI) [3], are superior to other methods because they offer a unique capability to determine all of these parameters. Contrary to other spectroscopic methods, such as nuclear magnetic resonance (NMR), which can only determine an average value of some of the above parameters [e.g., the number-average molecular weight (M n ) and number average-functionality (F n )], mass spectrometric methods provide not only these average values, but the individual intact polymer molecules can also be detected. However, because soft-ionization is based on forming adduct ions with metal ions, e.g., alkali or silver ions or through protonation and/or deprotonation, mass spectrometric analysis of polymers having moieties that are unable to form ions presents difficulties. This is more pronounced as the polarity of the polymers decreases. For example, mass spectrometric analysis of polar polymers such as polyethylene glycol (PEG) and polypropylene glycol (PPG) can easily be achieved using . Nonpolar polymers such as polystyrenes are also amenable to MALDI and ESI through the f...

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“…MALDI-TOF-MS: Characterization of the polymers was carried out by using a dithranol matrix with potassium trifluoroacetate in tetrahydrofuran (THF) solutions with a Bruker BIFLEX III mass spectrometer and a TOF analyzer by applying 19 kV total acceleration voltage, pulsed ion extraction, and a nitrogen laser (337 nm, 3 ns pulse width, 10 6 -10 7 W cm -2 ) at 4 Hz for laser desorption [21].…”

Section: Rheological Experimentsmentioning

confidence: 99%

Magnetic and Temperature‐Sensitive Release Gels from Supramolecular Polymers

Binder

Petraru

Roth

et al. 2007

Adv Funct Materials

116

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Supramolecular gels consisting of trivalent polyisobutylene and bivalent poly(ethylene oxide) are generated. Strong hydrogen bonding interactions, affixed to the end‐group moieties of the respective polymers (binding constant Kassn = 105 M–1), serve as molecular glue, leading to the formation of weak gels. Two different gels were prepared: one, with a short telechelic poly(ethylene glycol) (PEG) segment (gel A), and one with a longer PEG segment (number‐average molecular weight Mn = 2000 g mol–1) (gel B). Both gels show a significant increase in viscosity upon mixing of the two polymeric components, with a lag time of several minutes, indicative of nucleation mechanisms as the formation principle. However, only gel A displays classical gel‐like behavior, with a loss modulus G′ larger than the storage modulus G″ after formation. Both gels display microphase‐separated behavior with a spacing between 4–5 nm as probed via small‐angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) measurements. The incorporation of magnetic nanoparticles (Fe2O3; radius r = 3.5 nm) is successfully achieved, generating new magnetic gels with strongly thermoresponsive properties, displaying a strong temperature‐dependent release profile of included dye molecules. Magnetic measurements indicate a superparamagnetic behavior of the incorporated nanoparticles, prospecting the application as magneto‐sensitive delivery gels for pharmaceutical purposes.

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Novel and Simple Synthesis of Carboxyl-Terminated Polyisobutylenes

Cited by 12 publications

References 15 publications

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives

Magnetic and Temperature‐Sensitive Release Gels from Supramolecular Polymers

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