Thermal degradation of poly(methyl methacrylate). 3. Polymer with head-to-head linkages

Manring, Lewis E.; Sogah, Dotsevi Y.; Cohen, Gordon M.

doi:10.1021/ma00202a048

Cited by 149 publications

(80 citation statements)

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“…In general, the first stage was related to the depolymerization beginning from headto-head linkages; the second stage-to depolymerization starting from unsaturated vinyl ends; and the third stageto random chain scissions. Manring proposed somewhat different explanations for thermal degradation of PMMA [19][20][21]. He found that the presence of head-to-head structures made the temperature of degradation lower; however, decomposition of these structures took place rather at the second stage.…”

Section: Discussionmentioning

confidence: 99%

Thermogravimetric analysis of thermal stability of poly(methyl methacrylate) films modified with photoinitiators

Gałka

Kowalonek

Kaczmarek

2013

J Therm Anal Calorim

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Films of poly (methyl methacrylate) (PMMA) were prepared by the addition of photoinitiator to the polymer. The influence of five organic photoinitiators on thermal stability of poly(methyl methacrylate) was studied by thermogravimetric analysis. Next, the PMMA films doped with these photoinitiators were UV irradiated and investigated in terms of changes in their thermal stability. It was found that the photoinitiators had accelerated thermal degradation of non-irradiated PMMA films due to the action of free radicals coming from the additives' thermolysis. For UV-irradiated specimens, the effect of photoinitiator on PMMA thermal stability depended on the chemical structure of organic compound modifying the polymer. In general, thermal stability of irradiated samples was higher in the presence of additives. Thermal destruction of modified PMMA can be explained by the formation of resonance structures in aromatic photoinitiators and consumption of energy in dissipation processes.

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Section: Discussionmentioning

confidence: 99%

Thermogravimetric analysis of thermal stability of poly(methyl methacrylate) films modified with photoinitiators

Gałka

Kowalonek

Kaczmarek

2013

J Therm Anal Calorim

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“…PMMA is known to degrade by unzipping or depropagation which can be initiated at weak links or by random chain scission. [40][41][42][43][44][45][46][47][48] Any structures that are less stable than the backbone or side chain bonds and which give rise to propagating radicals may constitute weak links. PMMA formed by conventional radical polymerization in the absence of transfer agents is known to contain weak links formed as a consequence of termination by combination or disproportionation.…”

Section: Discussionmentioning

confidence: 99%

Thermolysis of RAFT-Synthesized Poly(Methyl Methacrylate)

et al. 2006

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Thermolysis provides a simple and efficient way of eliminating thiocarbonylthio groups from RAFT-synthesized polymers. The course of thermolysis of poly(methyl methacrylate) (PMMA) prepared with dithiobenzoate and trithiocarbonate RAFT agents was followed by thermogravimetric analysis (TGA), 1 H NMR spectroscopy, and gel permeation chromatography (GPC). The weight loss profile observed depends strongly on the RAFT agent used during polymer synthesis. PMMA with a methyl trithiocarbonate end group undergoes loss of that end group at ∼180 • C, at least in part, by a mechanism believed to involve homolysis of the C-CS 2 SCH 3 bond and subsequent depropagation. In contrast, PMMA with a dithiobenzoate end appears more stable. Only the end group is lost at ∼180 • C and the dominant mechanism is proposed to be a concerted elimination process analogous to that involved in the Chugaev reaction.

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“…Mechanisms of thermal degradation such as depolymerization, scission of side chains, and dissociation of the polymer backbones take place depending on the environment, temperature, molecular weight, chain end groups, chain configuration, polymerization condition etc. [68][69][70][71][72][73][74][75][76][77][78][79][80][81][82] As such, the activation energy of thermal degradation varies widely. It is generally found to be between 1.87 eV and 3.34 eV for PS in an inert atmosphere or vacuum [71], and from 1.23 eV to 3.55 eV for PMMA in an inert atmosphere [70, 72-74, 77, 79-81].…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic studies of the mechanism of reversible photodegradation of 1-substituted aminoanthraquinone-doped polymers

Hung

Bhuyan

Schademan

et al. 2016

The Journal of Chemical Physics

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The mechanism of reversible photodegradation of 1-substituted aminoanthraquinones doped into poly(methyl methacrylate) and polystyrene is investigated. Time-dependent density functional theory is employed to predict the transition energies and corresponding oscillator strengths of the proposed reversibly-and irreversibly-damaged dye species. Ultraviolet-visible and Fourier transform infrared (FTIR) spectroscopy are used to characterize which species are present. FTIR spectroscopy indicates that both dye and polymer undergo reversible photodegradation when irradiated with a visible laser. These findings suggest that photodegradation of 1-substituted aminoanthraquinones doped in polymers originates from interactions between dyes and photoinduced thermally-degraded polymers, and the metastable product may recover or further degrade irreversibly. INTRODUCTIONOrganic materials have a broad range of applications such as high-resolution fluorescence microscopy [1][2][3][4][5][6][7], second harmonic generation (SHG) microscopy [8][9][10][11][12], dye sensitized and polymer solar cells [13][14][15][16][17], solid state dye/organic lasers [18][19][20], and organic light emitting diodes [21,22], to name a few. Photostability of organic compounds and polymers is often a requirement for applications incorporating light-matter interaction [2-4, 6, 8, 18-20, 23-30]. When a material undergoes photodegradation, its characteristic properties deteriorate over time, which is referred to as decay; the reverse change in the characteristic properties of the material is referred to as recovery. Though photodegradation is often irreversible, the recovery process has been observed from a large variety of materials, typically involving polymers and often together with dyes, with various experimental techniques when the photodegraded materials are kept in dark for a long enough time, typically hours to days [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44].Amplified spontaneous emission (ASE) of disperse orange 11 (DO11) doped in poly(methyl methacrylate) (PMMA) bulk sample was observed to fully recover in the dark about 40 hours after photodegradation when irradiated with a 532 nm second harmonic Nd:YAG picosecond laser [33]. This self-healing phenomenon was also observed in various anthraquinone derivatives doped in PMMA and polystyrene (PS) thin films [41,42] and DO11 doped in MMA-styrene copolymers thin films [42,45] probed with transmittance image microscopy and ASE. The photodegraded thin film samples are often observed to recover partially, which suggests there exists both reversible and irreversible photodegradation. The lack of evidence for linear dichroism during photodegradation measurements eliminates orientational hole burning as the mechanism causing reversible photodegra- [38,42,46,[50][51][52][53][54], they have failed to elucidate the underlying mechanism.Several hypotheses of the mechanism responsible for reversible photodegradation in DO11/PMMA have been proposed, including intramolecular proton transfer and ...

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Thermal degradation of poly(methyl methacrylate). 3. Polymer with head-to-head linkages

Cited by 149 publications

References 1 publication

Thermogravimetric analysis of thermal stability of poly(methyl methacrylate) films modified with photoinitiators

Thermogravimetric analysis of thermal stability of poly(methyl methacrylate) films modified with photoinitiators

Thermolysis of RAFT-Synthesized Poly(Methyl Methacrylate)

Spectroscopic studies of the mechanism of reversible photodegradation of 1-substituted aminoanthraquinone-doped polymers

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