Analysis of Double Bond Conversion of Photopolymerizable Monomers by FTIR-ATR Spectroscopy

This work reports the use of two monomers with two tertiary amines and four methacrylic (TTME) or acrylic (TTAC) terminal groups as co-initiators in the formulation of experimental resin adhesive systems. Both monomers were characterized by FT-IR and 1H NMR spectroscopies. The control adhesive was formulated with BisGMA, TEGDMA, HEMA, and the binary system CQ-EDAB as a photo-initiator system. For the experimental adhesives, the EDAB was completely replaced for the TTME or the TTAC monomers. The adhesives formulated with TTME or TTAC monomers achieved double bond conversion values close to 75%. Regarding the polymerization rate, materials formulated with TTME or TTAC achieved lower values than the material formulated with EDAB, giving them high shelf-life stability. The degree of conversion after shelf simulation was only reduced for the EDAB material. Ultimate tensile strength, translucency parameter, and micro-tensile bond strength to dentin were similar for control and experimental adhesive resins. Due to their characteristics, TTME and TTAC monomers are potentially useful in the formulation of photopolymerizable resins for dental use with high shelf-life stability.

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Depth-Related Curing Potential of Ormocer- and Dimethacrylate-Based Bulk-Fill Composites

Materials ◽

10.3390/ma14226753 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6753

Author(s):

Ramona S. Oltramare ◽

Reto Odermatt ◽

Phoebe Burrer ◽

Thomas Attin ◽

Tobias T. Tauböck

Keyword(s):

Double Bond ◽

Repeated Measures ◽

In Vitro Study ◽

High Viscosity ◽

Degree Of Conversion ◽

Double Bond Conversion ◽

Nanohybrid Composite ◽

Post Hoc ◽

One Way Anova

The aim of this in vitro study was to investigate the degree of C=C double bond conversion of high-viscosity dimethacrylate- or ormocer-based bulk-fill composites as a function of measurement depth. Four bulk-fill composites (Tetric EvoCeram Bulk Fill, x-tra fil, SonicFill, and Bulk Ormocer) and the conventional nanohybrid composite Tetric EvoCeram were applied in standardized Class II cavities (n = 6 per group) and photoactivated for 20 s at 1350 mW/cm2. The degree of conversion of the composites was assessed using Fourier-transform infrared spectroscopy at seven measurement depths (0.15, 1, 2, 3, 4, 5, 6 mm). Data were analyzed using repeated measures ANOVA and one-way ANOVA with Bonferroni post-hoc tests (α = 0.05). The investigated bulk-fill composites showed at least 80% of their maximum degree of conversion (80% DCmax) up to a measuring depth of at least 4 mm. Tetric EvoCeram Bulk Fill and Bulk Ormocer achieved more than 80% DCmax up to a measuring depth of 5 mm, x-tra fil up to 6 mm. The conventional nanohybrid composite Tetric EvoCeram achieved more than 80% DCmax up to 3 mm. In contrast to the conventional composite, the investigated ormocer- and dimethacrylate-based bulk-fill composites can be photo-polymerized in thick layers of up to at least 4 mm with regard to their degree of C=C double bond conversion.

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Using a new approach to analyze a depth profile of double bond conversion in model formulations

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2007.09.042 ◽

2008 ◽

Vol 61 (2-4) ◽

pp. 176-180 ◽

Cited By ~ 5

Author(s):

R. Bao ◽

S. Jönsson

Keyword(s):

Double Bond ◽

Depth Profile ◽

New Approach ◽

Double Bond Conversion

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Novel Bioadhesives for Restorative Dentistry

Materials Science Forum ◽

10.4028/www.scientific.net/msf.587-588.682 ◽

2008 ◽

Vol 587-588 ◽

pp. 682-686

Author(s):

S.G. Pereira ◽

J.P. Telo ◽

R. Osorio ◽

M. Toledano ◽

Teresa G. Nunes

Keyword(s):

Free Radical ◽

Double Bond ◽

Epr Spectroscopy ◽

Stray Field ◽

Restorative Dentistry ◽

Radical Scavengers ◽

Spatially Resolved ◽

Radical Concentration ◽

Free Radical Concentration ◽

Double Bond Conversion

The objective of this study was to develop new adhesive formulations based on 2,2-bis[4-(2- methacryloxyprop-1-oxy) phenyl] propane (CH3-BisGMA) aiming to obtain high double bond conversion (DC) even in the presence of radical scavengers and monomers with acidic groups. NMR, EPR spectroscopy and spatially-resolved 1H Stray-Field MRI observations enabled to study the influence of the composition in DC, free radical concentration, reactivity of the monomers and volumetric contraction.

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Systematic Approach to the Synthesis of Organic-Inorganic Nanocomposites Based on Dmta Measurements and Ir Spectroscopy

MRS Proceedings ◽

10.1557/proc-519-387 ◽

1998 ◽

Vol 519 ◽

Cited By ~ 1

Author(s):

Peter Müller ◽

Carsten Becker ◽

Helmut Schmidt

Keyword(s):

Double Bond ◽

Ir Spectroscopy ◽

Hybrid Materials ◽

Strong Dependence ◽

Sol Gel ◽

Thermomechanical Properties ◽

Thermal Curing ◽

Molar Ratios ◽

Double Bond Conversion ◽

Titania Sol

AbstractSol-gel derived organic-inorganic hybrid materials with potential fields of application as refractive optical components for example laser diode bars and ophthalmic lenses are presented. The main components of the hybrid materials under investigation are precondensed methacryloxypropyltrimethoxysilane (MPTS, denoted: M) with an organically polymerisable methacrylic functionality and tetraethyleneglycoldimethacrylate (TEGDMA, denoted: T) as crosslinking organic monomer with two polymerisable double bonds. The molar ratios of the components ranged from M/T 10/90 up to M/T 70/30. The polymer derived from pure TEGDMA (M/T 0/100) served as a reference material. In addition to this nanoscaled TiO2 particles (5 wt.% and 10 wt.%) were incorporated in the organic-inorganic M/T 30/70 matrix to increase the refractive index of the resulting nanocomposites. For the preparation of the different systems, precondensed MPTS was mixed with TEGDMA, the nanoparticulate titania sol (when used), an appropriate photoinitiator and a thermoinitiator. The reaction mixtures were polymerised photochemically and/or thermally. The propagation of the free radical polymerisation reaction after photopolymerisation and subsequent thermal curing was followed by IR-spectroscopy, showing that the degree of double bond conversion is strongly increased by the thermal curing step. Incorporation of increasing amounts of TiO2 nanoparticles resulted in reduction of the double bond conversion compared to the corresponding unfilled system. The homogeneous dispersion of the titania particles in the completely cured M/T 30/70 matrix could be manifested by high resolution transmission electron microscopy (HTEM). The thermomechanical properties of the completely cured nanocomposites were monitored by dynamic mechanical thermal analysis (DMTA) showing a strong dependence on composition.

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