Photocatalytic degradation of methyl methacrylate copolymers

Vinu, R.; Madras, Giridhar

doi:10.1016/j.polymdegradstab.2008.05.018

Cited by 31 publications

(21 citation statements)

References 39 publications

(51 reference statements)

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“…On the other hand, methacrylate polymers are in general less prone to crosslinking, because of the higher stability of the tertiary macroradicals formed [22]. Main chain scission is therefore prevalent in poly(methyl methacrylate) [19]. Very similar results were obtained by Fox et al [21] as well.…”

Section: Ftireatr Studies E Degradation Mechanismssupporting

confidence: 58%

“…10. Vinu et al [19] obtained similar results regarding the photocatalytic degradation of poly(methyl methacrylate) copolymers by TiO 2 . They allocated the formation of a shoulder in the 240e290 nm region to the forbidden pep* transition, characteristic for the absorption of aldehydes and ketones.…”

Section: Uvevis Studies E Uva Degradation Kinetics and Mechanismsmentioning

confidence: 67%

“…This band can be attributed to the hydroxyl stretching vibration. Vinu et al [19] obtained the same results of the degradation behaviour on various acrylate-copolymers and allocated it to the attack of the *OH radicals and the subsequent formation of polymer hydroperoxy radicals. Fig.…”

Section: Ftir Studies E Binder Degradation Kineticsmentioning

confidence: 82%

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The effects of HALS in the prevention of photo-degradation of acrylic clear topcoats and wooden surfaces

Forsthuber¹,

Grüll²

2010

Polymer Degradation and Stability

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Section: Ftireatr Studies E Degradation Mechanismssupporting

confidence: 58%

Section: Uvevis Studies E Uva Degradation Kinetics and Mechanismsmentioning

confidence: 67%

See 1 more Smart Citation

The effects of HALS in the prevention of photo-degradation of acrylic clear topcoats and wooden surfaces

Forsthuber¹,

Grüll²

2010

Polymer Degradation and Stability

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“…Entretanto, é importante ressaltar que o desempenho térmico dos copolímeros de MMA, GMA e MAA pode ser ligeiramente diferente. Por exemplo, de acordo com Vinu e Madras [29] , o poli (MMA-co-MAA) apresenta um único estágio de decomposição a 400°C. Na pirólise de polímeros, o principal fenômeno que ocorre é a despolimerização da cadeia com a formação de estruturas como álcoois e anidridos, entretanto na decomposição do poli(MMA-co-MAA) existe um mecanismo diferente.…”

Section: Figura 2 Espectros De Atr-ir Para Os Polímeros (A) Madeiraunclassified

Compósitos polímero-madeira preparados por polimerização in situ de metil metacrilato usando aditivos bifuncionais

et al. 2015

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ResumoO presente trabalho teve por objetivo a confecção de compósitos polímero-madeira por meio de polimerização in situ de metil metacrilato (MMA), utilizando ácido metacrílico (MAA) e glicidil metacrilato (GMA) como agentes de ligação e reticulação. Amostras de madeira de guapuruvu foram impregnadas em um sistema de vácuo e pressão e polimerizadas em estufa a 90°C por 10h, usando 1,5% de peroxido de benzoíla como catalisador. Os compósitos foram caracterizados por meio de testes de absorção de água e estabilidade dimensional, molhabilidade, ATR-IR, TGA, MEV e WPG. Os espectros de ATR-IR mostraram incrementos nas bandas a 1746, 1460, e 1145 cm -1 , referentes as estruturas químicas dos polímeros dentro da madeira, confirmado posteriormente pelas imagens de MEV. A termogravimetria apontou reações químicas entre os copolímeros e a parede celular da madeira nos compósitos com GMA e MAA. Os compósitos preparados com MMA apresentaram incrementos acima de 50% nas propriedades higroscópicas e de estabilidade dimensional, entretanto a adição de GMA e MAA resultou em maiores incrementos nas mesmas propriedades, entre 66-90%. Palavras-chave: polimerização por radicais livres, Schizolobium parahyba, catálise térmica, reticulantes, agentes de ligação. AbstractWe prepared wood/polymer composites by in situ polymerization of methyl methacrylate (MMA) using glycidyl methacrylate (GMA) and methacrylic acid (MAA) as cross-linkers and coupling agents. The guapuruvu wood samples were impregnated in a vacuum/pressure system and polymerized at 90 °C for 10 h, using benzoyl peroxide at 1.5 wt % as catalyst. We characterized the composites through water uptake, dimensional stability tests, wettability, ATR-FTIR spectroscopy, TGA, SEM, and WPG. ATR-FTIR spectra showed an increase of the peaks at 1746, 1460, and 1145 cm -1 , corresponding to the chemical structures of the polymers into the pores and capillaries of the wood. This was further confirmed in the SEM images. TGA curves showed evidences for a chemical interaction between the copolymer and the wood cell wall in the composites with GMA and MAA. Hygroscopicity and dimensional stability properties of the composites prepared with MMA improved by 50%. Nevertheless, the addition of GMA and MAA resulted in additional increases for hydrophobicity and dimensional stability of the samples, ~ 66 -90%.

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“…15 High-intensity ultrasonic treatment can be applied to degrade polymers and to facilitate emulsifying and cleaning processes in homogenous liquid phase. 16 The ultrasonic energy is dissipated in solution, resulting in cavitations. Cavitation produces vibrational wave energy, shear stresses at the cavitation interphase, and local high pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

A kinetic study of ultrasonic degradation of carboxymethyl cellulose

Taghizadeh

Abdollahi

2011

J of Applied Polymer Sci

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In this study, the effect of power of ultrasound, temperature, and concentration of carboxymethyl cellulose (CMC) solution on the rate of ultrasonic degradation were investigated, and a kinetic model based on viscometry data was used to calculate the rate constants in different conditions. To investigation of effect of ultrasonic power on the degradation of CMC, the power of ultrasound was increased and observed that the viscosity of the CMC solution was decreased with an increase in the power of ultrasound, but the extent of the degradation in a constant power was found to decrease with an increase in concentration or temperature. The ultrasonic degradation of CMC solutions was carried out at different temperatures to investigate the effect of the temperature on the rate of degradation. The calculated rate constants indicated that the degradation rate of the CMC solutions decreased as the temperature increased. The degraded CMCs were characterized by gel permeation chromatography, and average molecular weights of ultrasonicated CMCs were compared in different reaction conditions.

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Photocatalytic degradation of methyl methacrylate copolymers

Cited by 31 publications

References 39 publications

The effects of HALS in the prevention of photo-degradation of acrylic clear topcoats and wooden surfaces

The effects of HALS in the prevention of photo-degradation of acrylic clear topcoats and wooden surfaces

Compósitos polímero-madeira preparados por polimerização in situ de metil metacrilato usando aditivos bifuncionais

A kinetic study of ultrasonic degradation of carboxymethyl cellulose

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