Investigations on the dissociation behavior of hydrolyzed alternating copolymers of maleic anhydride and alkenes:13C-NMR spectra and potentiometric titrations

Reinhardt, Steffi; Komber, Hartmut; Steinert, Volker

doi:10.1002/(sici)1099-0518(19960915)34:12<2415::aid-pola16>3.0.co;2-b

Cited by 8 publications

(9 citation statements)

References 12 publications

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“…Aqueous solutions of various alternating copolymers of maleic acid have been investigated by means of potentiometric and conductometric titrations, intrinsic viscosity measurements, NMR studies, and theoretical approaches. − The results of those studies demonstrate that electrostatic forces, hydrogen bonds, and hydrophobic interactions cause the particular behavior of the dissolved copolymers. The carboxylic acid groups of the maleic acid unit appear to dissociate in two steps as if the acid groups would exhibit two distinct p K values.…”

Section: Introductionmentioning

confidence: 99%

Ionization Characteristics and Structural Transitions of Alternating Maleic Acid Copolymer Films

Osaki

Werner

2003

Langmuir

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Alternating maleic acid copolymers dissolved in aqueous solutions exhibit characteristic two-step dissociation profiles and pH-induced structural transitions in dependence on the comonomer unit. In extension of these findings, we analyzed a set of thin films of maleic acid copolymers (poly(octadecenealt-maleic acid), POMA; poly(propylene-alt-maleic acid), PPMA; poly(styrene-alt-maleic acid), PSMA) randomly attached to planar glass surfaces by covalent binding. Streaming potential/streaming current measurements with a microslit electrokinetic setup (MES) were applied to determine zeta potential (ζ) and surface conductivity (K σ ) data of the polymer layers in aqueous solutions of varied pH. The results confirmed the two-step dissociation behavior for all immobilized copolymers. A dramatic increase of K σ was observed for PPMA and PSMAsbut not for POMAslayers at alkaline pH values, indicating that electrostatic repulsion of ionized groups controls the extension of the confined layers as long as hydrophobic interactions between the comonomers do not inhibit this effect. The isoelectric points (IEPs) show that for PPMA and PSMA layers the acidic functions dominate the interfacial charging and exhibit an enhanced acidity which can be explained by hydrogen bonds between the anion formed in the first dissociation and the proton of the adjacent undissociated group. In contrast, the layered POMA exhibits significantly less acidic IEP values due to the large comonomer. Hysteresis effects of the ζ versus pH profiles were observed for dissociation and association of the copolymers. This was explained by the reduced dynamics of structural transitions in the immobilized layers as compared to the dissolved molecules.

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Section: Introductionmentioning

confidence: 99%

Ionization Characteristics and Structural Transitions of Alternating Maleic Acid Copolymer Films

Osaki

Werner

2003

Langmuir

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“…Such data were reported in several papers regarding maleic acid copolymers with alkenes, alkyl vinyl ethers, styrene, , indene, and p -styrenesulfonic acid . Recently, the dissociation behavior of maleic acid−alkene copolymers was investigated and more than two p K a values were determined ascribed to the existence of erythro and threo configurations …”

Section: Introductionmentioning

confidence: 57%

“…8 Recently, the dissociation behavior of maleic acid-alkene copoly-mers was investigated and more than two pK a values were determined ascribed to the existence of erythro and threo configurations. 9 Maleic acid copolymers are obtained in most cases by hydrolysis of maleic anhydride copolymers that are generally known as 1:1 alternating copolymers. 2,10 Consequently, in maleic acid copolymers the distribution of the charges along the chain is more uniform than that for other copolymers.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Nonalternating Maleic Acid Copolymers in Aqueous Solution

et al. 1999

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A nonalternating 1:3 maleic acid−methyl methacrylate copolymer was synthesized and characterized, and its polyelectrolyte behavior was studied by potentiometric and conductometric titrations. Two intrinsic dissociation constants were found equal to 3.5 and 7.6, and only a slight influence of the nature of the counterions and of the presence of added salt (0.1 M) was observed. The transport coefficients, determined from conductometry, for mono- and divalent cations were in relatively good agreement with the values calculated from Manning theory, especially at low polymer concentrations. A conformational change around αN ∼ 0.25 was confirmed by means of viscometric and fluorescence measurements.

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“…It is known that a difference of pK % 1-2 is needed to differentiate the dissociation behavior. It was shown by combined titration and NMR experiments that it is possible to resolve small differences in the acidic strength, [22] but we neglected the effect since its impact is low.…”

Section: Dissociation Behaviormentioning

confidence: 99%

Influence of Grafting on the Solution Properties and the Dissociation Behavior of Ionic/Nonionic Grafted Copolymers

Weber

Boyko

Arndt

2007

Macro Chemistry & Physics

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A new synthetic approach towards grafted terpolymers based on a poly[(methyl vinyl ether)‐alt‐(maleic anhydride)] backbone and poly(ethylene glycol) monomethyl ether (MPEG) side chains is presented. Resulting comb polymers with controllable grafting degree still have highly reactive anhydride moieties along the polymer backbone, as proved by IR spectroscopy. Grafting degree depends on the anhydride hydroxide stoichiometric ratio. It is not influenced by the molecular weight of MPEG. An increase in the grafting degree leads to a contraction of the polymer in the solution. Evaluation of potentiometric titration data gave a deeper insight into the dissociation process. The copolymers showed a two‐step dissociation behavior. No significant influence of the grafting degree on the acidic strength was observed, whilst there is a strong effect of the grafting degree on the free energy change upon neutralization ΔGel. Grafting leads to a higher change in free energy ΔGel,1 for the first step but to lower ΔGel,2 required for the second step.magnified image

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Investigations on the dissociation behavior of hydrolyzed alternating copolymers of maleic anhydride and alkenes:13C-NMR spectra and potentiometric titrations

Cited by 8 publications

References 12 publications

Ionization Characteristics and Structural Transitions of Alternating Maleic Acid Copolymer Films

Ionization Characteristics and Structural Transitions of Alternating Maleic Acid Copolymer Films

Behavior of Nonalternating Maleic Acid Copolymers in Aqueous Solution

Influence of Grafting on the Solution Properties and the Dissociation Behavior of Ionic/Nonionic Grafted Copolymers

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