Determination of Neutralization Capacity and Stability of a Basic Methacrylate Monomer Using NMR

Park, Jong-Gu; Ye, Qiang; Spencer, Paulette; Laurence, Jennifer S.

doi:10.1080/00914037.2011.574660

Cited by 9 publications

(9 citation statements)

References 20 publications

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“…PDMAEMA is a polybase that has a critical pH point around 7, which is close to the physiological pH [27]. However, DMAEMA has been shown to be unstable in basic solution by nuclear magnetic resonance (NMR) and can be completely hydrolyzed into methacrylic acid and dimethylaminoethanol, as shown in our previous work [28]. 2- N -morpholinoethyl methacrylate (MEMA) is another basic monomer with a p K a 6.2 and is able to neutralize LA more effectively than DMAEMA [26].…”

Section: Introductionmentioning

confidence: 99%

Compositional design and optimization of dentin adhesive with neutralization capability

Song

et al. 2015

Journal of Dentistry

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Objectives The objective of this work was to investigate the polymerization behavior, neutralization capability, and mechanical properties of dentin adhesive formulations with the addition of the tertiary amine co-monomer, 2-N-morpholinoethyl methacrylate (MEMA). Methods A co-monomer mixture based on HEMA/BisGMA (45/55, w/w) was used as a control adhesive. Compared with the control formulation, the MEMA-containing adhesive formulations were characterized comprehensively with regard to water miscibility of liquid resin, water sorption and solubility of cured polymer, real-time photopolymerization kinetics, dynamic mechanical analysis (DMA), and modulated differential scanning calorimetry (MDSC). The neutralization capacity was characterized by monitoring the pH shift of 1 mM lactic acid (LA) solution, in which the adhesive polymers were soaked. Results With increasing MEMA concentrations, experimental copolymers showed higher water sorption, lower glass transition temperature and lower crosslinking density compared to the control. The pH values of LA solution gradually increased from 3.5 to about 6.0–6.5 after 90 days. With the increase in crosslinking density of the copolymers, the neutralization rate was depressed. The optimal MEMA concentration was between 20 and 40 wt%. Conclusions As compared to the control, the results indicated that the MEMA-functionalized copolymer showed neutralization capability. The crosslinking density of the copolymer networks influenced the neutralization rate.

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Section: Introductionmentioning

confidence: 99%

Compositional design and optimization of dentin adhesive with neutralization capability

Song

et al. 2015

Journal of Dentistry

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“…The 13 C NMR spectrum of 0.1 M lactic acid (LA) in water at pH 2 yields peaks at 19.22 ppm, 66.38 ppm, and 178.59 ppm 5 . The peak at 178.59 corresponds to the carboxyl carbon in its fully protonated state, and the position of this peak is sensitive to changes in pH.…”

Section: Resultsmentioning

confidence: 99%

“…It was determined from our previous study that the carbon within the carboxylic acid moiety of LA is an excellent probe for tracking the pH of the solution, because its chemical shift position reflects the protonation state of this group 5 . 13 C NMR spectra of LA were collected in the presence of various amounts of ethanol and the chemical shift position of the carboxyl carbon monitored (Figure 1B).…”

Section: Resultsmentioning

confidence: 99%

“…To protect against acid-induced degradation, incorporation of basic monomers capable of neutralization is being investigated for next generation dental polymers. We previously demonstrated NMR may be used to track lactic acid neutralization in aqueous solution by monitoring the chemical shift of the carboxyl carbon in LA 5 . Because dental adhesive is hydrophobic and the oral environment is aqueous, miscibility of the basic monomer with both resin and water is an important aspect of compatibility with the formulation.…”

Section: Discussionmentioning

confidence: 99%

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Characterization of Acid-Neutralizing Basic Monomers in Co-Solvent Systems by NMR

Laurence¹,

Nelson²,

Ye³

et al. 2014

International Journal of Polymeric Materials and Polymeric Biom

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Metabolic activity of the oral microbiota leads to acidification of the microenvironment and promotes demineralization of tooth structure at the margin of composite restorations. The pathogenic impact of the biofilm at the margin of the composite restoration could be reduced by engineering novel dentin adhesives that neutralize the acidic micro-environment. Integrating basic moieties into methacrylate derivatives has the potential to buffer against acid-induced degradation, and we are investigating basic monomers for this purpose. These monomers must be compatible with existing formulations, which are hydrophobic and marginally miscible with water. As such, cosolvent systems may be required to enable analysis of monomer function and chemical properties. Here we present an approach for examining the neutralizing capacity of basic methacrylate monomers in a water/ethanol co-solvent system using NMR spectroscopy. NMR is an excellent tool for monitoring the impact of co-solvent effects on pKa and buffering capacity of basic monomers because chemical shift is extremely sensitive to small changes that most other methods cannot detect. Because lactic acid (LA) is produced by oral bacteria and is prevalent in this microenvironment, LA was used to analyze the effectiveness of basic monomers to neutralize acid. The 13C chemical shift of the carbonyl in lactic acid was monitored as a function of ethanol and monomer concentration and each was correlated with pH to determine the functional buffering range. This study shows that the buffering capacity of even very poorly water-soluble monomers can be analyzed using NMR.

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“…The addition of increasing amounts of 2-dimethyl-aminoethyl methacrylate (DMAEMA), which contains a basic amine, does however, shift the pH of the acidic LA solution making it more neutral. These data show that neutralization can be achieved by monomers such as DMAEMA and that the buffering capacity can be measured in a simple NMR experiment using LA as a probe [152] .…”

Section: Vb Novel Interventionsmentioning

confidence: 91%

Durable bonds at the adhesive/dentin interface:an impossible mission or simply a moving target?

Spencer¹,

Ye²,

Park³

et al. 2012

BDS

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Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.

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Determination of Neutralization Capacity and Stability of a Basic Methacrylate Monomer Using NMR

Cited by 9 publications

References 20 publications

Compositional design and optimization of dentin adhesive with neutralization capability

Compositional design and optimization of dentin adhesive with neutralization capability

Characterization of Acid-Neutralizing Basic Monomers in Co-Solvent Systems by NMR

Durable bonds at the adhesive/dentin interface:an impossible mission or simply a moving target?

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