Thermal decomposition of copolymers used in dental resins formulations photocured by ultra blue IS

Rigoli, Isabel C.; Cavalheiro, Carla Cristina Schmitt; Neumann, Miguel G.; Cavalheiro, Éder Tadeu Gomes

doi:10.1002/app.26598

Cited by 12 publications

(7 citation statements)

References 29 publications

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“…In a general there is a small mass loss since the starting of the heating up to 200-240 °C depending on the sample. This mass loss is accompanied by an endothermic process in the DTA curve and was attributed to the loss of residual volatiles [13].…”

Section: Tg-dta Curvesmentioning

confidence: 99%

THERMOANALYTICAL STUDY OF MONOMERS: BisGMA, BisEMA, TEGDMA, UDMA

Cavalheiro¹,

Bannach²,

Cavalheiro

et al. 2015

Braz. J. Therm. Anal.

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Thermal behavior of BisGMA (bisphenylglycidyl dimethacrylate), TEGDMA (triethylene glycol dimethacrylate), BisEMA (ethoxylated bisphenol-A dimethacrylate), UDMA (Urethane dimethacrylate) monomers and one their mixtures was investigated by TG-DTA, DSC and coupled TG-FTIR. TG-DTA curves of monomers showed that the isolated compounds starts decomposition between 178-297 ºC and mixture of fotocured monomers starts decomposition at 250ºC. The TG-FTIR was used to characterize volatiles released during the thermal cure before thermal decomposition. The DSC curves showed the glass transition, melting point and crystallization temperatures of the samples.

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Section: Tg-dta Curvesmentioning

confidence: 99%

THERMOANALYTICAL STUDY OF MONOMERS: BisGMA, BisEMA, TEGDMA, UDMA

Cavalheiro¹,

Bannach²,

Cavalheiro

et al. 2015

Braz. J. Therm. Anal.

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“…The second peak at 360°C may be attributed to the scission of low molecular weight, thermal decomposition products from the cross-linked bis-GMA and TEGDMA. The third peak at 424°C is associated with the decomposition reaction that led to the generation of the low molecular weight decomposition products (methacrylic acid and hydroxyethyl methacrylate) [27]. For the bis-GMA/QAMS-3 PH system, the initial mass loss up to 167°C may be attributed to the evaporation of free and bound methanol solvent, as well as volatilization of unreacted components within the monomer mix.…”

Section: Resultsmentioning

confidence: 99%

Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential

et al. 2012

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Design of antimicrobial polymers for enhancing healthcare issues and minimizing environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol-gel chemical route; these compounds possess flexible Si-O-Si bonds. In present work, a partially-hydrolyzed QAMS copolymerized with bis-GMA is introduced. This methacrylate resin was shown to possess desirable mechanical properties with both a high degree of conversion and minimal polymerization shrinkage. Kill-on-contact microbiocidal activities of this resin were demonstrated using single-species biofilms of Streptococcus mutans (ATCC 36558), Actinomyces naeslundii (ATCC 12104) and Candida albicans (ATCC 90028). Improved mechanical properties after hydration provided the proof-of-concept that QAMS-incorporated resin exhibits self-repair potential via water-induced condensation of organic modified silicate (ormosil) phases within the polymerized resin matrix.

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“…A termogravimetria (TG) é uma técnica muito usada para a determinação de parâmetros cinéticos, devido a sua simplicidade e inúmeras informações que podem ser obtidas das análises como energia de ativação e ordem de reação [10][11][12][13][14][15].…”

Section: Introductionunclassified

“…Entretanto, o método de FLYNN e WALL é limitado para decomposições de estágios simples e de cinéticas de primeira ordem [13,14].…”

Section: Introductionunclassified

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Influência de colorantes na degradação termo-oxidativa do policarbonato

Saron¹,

Felisberti

2009

Matéria (Rio J.)

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RESUMOCorantes e pigmentos são incorporados aos polímeros principalmente para melhorar suas propriedades estéticas. Porém, estes aditivos podem afetar a estabilidade térmica e fotoquímica do material. Este trabalho teve como objetivo estudar a influência de diferentes classes de colorantes sobre a estabilidade termo-oxidativa do policarbonato (PC), empregando os pigmentos à base de diazo de condensação e vanadato de bismuto e os corantes do tipo antraquinona e ftalocianina de cobre. Para tanto, foram realizados ensaios termogravimétricos no modo dinâmico em diferentes taxas de aquecimento e avaliadas as taxas de conversão, determinadas pela derivação das curvas termogravimétricas, e as energias de ativação, determinadas segundo o método de FLYNN e WALL. A análise da taxa de conversão revelou que a decomposição do PC contendo ou não colorantes ocorre em três etapas principais, porém a velocidade nestas etapas para o PC com colorantes é, na maioria dos casos estudados, superior à taxa de decomposição do PC puro. Isto indica que os colorantes estudados aceleram a degradação do PC. Entretanto, a energia de ativação calculada segundo o método de FLYNN e WALL não apresentou a mesma tendência observada nos resultados obtidos a partir das taxas de decomposição, sugerindo que a decomposição do PC não deve ser regida por uma cinética de primeira ordem, conforme se baseia o modelo de FLYNN e WALL.Palavras-chaves: policarbonato, decomposição térmica, colorantes, energia de ativação. Influence of colorants on thermo-oxidative degradation of polycarbonate ABSTRACTDyes and pigments are additives used in polymer systems to change the original coloration of the material. However, the thermal and photochemical stability of the polymer is frequently affected with the incorporation of these additives. The aim of this work was to study the influence of different colorant types (bismuth vanadate pigment, condensation diazo pigment, Cu-phthalocyanine dye and anthraquinone dye) on the thermo-oxidative stability of polycarbonate. Dynamic thermogravimetric analysis at different heating rate were carried out to evaluate the decomposition behavior of the material and to calculate the activation energy related to the decomposition process according to the FLYNN and WALL method. The curves of conversion rate showed that the polycarbonate with or without colorants present three steps of thermal decomposition, however the decomposition rate in theses steps for polycarbonate containing colorants is almost always higher than in polycarbonate without colorants. This indicates that the colorants accelerate the polycarbonate decomposition. On the other hand, the activation energy did not present the same behavior found to curves of conversion rate, suggesting that the decomposition reaction of polycarbonate does not follow a first order kinetic such as is based the FLYNN and WALL method.Keywords: polycarbonate, thermal decomposition, colorants, activation energy. INTRODUÇÃODurante todo o ciclo de vida útil os polímeros são submetidos a diversas con...

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Thermal decomposition of copolymers used in dental resins formulations photocured by ultra blue IS

Cited by 12 publications

References 29 publications

THERMOANALYTICAL STUDY OF MONOMERS: BisGMA, BisEMA, TEGDMA, UDMA

THERMOANALYTICAL STUDY OF MONOMERS: BisGMA, BisEMA, TEGDMA, UDMA

Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential

Influência de colorantes na degradação termo-oxidativa do policarbonato

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