Thermal degradation of poly(methyl methacrylate). 4. Random side-group scission

Manring, Lewis E.

doi:10.1021/ma00011a040

Cited by 203 publications

(112 citation statements)

References 5 publications

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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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Section: Discussionmentioning

confidence: 99%

Thermolysis of RAFT-Synthesized Poly(Methyl Methacrylate)

et al. 2006

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“…Thermal degradation of polymers has been studied extensively for several decades, and the dominant products of thermal degradation of PS and PMMA are known to be their monomers, styrene and MMA, respectively [68][69][70]. 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.…”

Section: Introductionmentioning

confidence: 99%

“…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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“…The thermal behavior of methacrylate polymers having a polar functional side group such as C=O, O-H can change via interchain and intra-chain of the side groups which results in cyclization, crosslinking, and so on [6][7][8]. In the recent years, investigations on thermal degradation of methacrylate and acrylate polymers having different side groups [9][10][11] have also been recorded in the literature. The chemical structure of a polymer having a reactive side group may change through interchain and intra-chain of the side groups resulting in the formation of a cross-linked and cyclic ladder structure during degradation of the polymer [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, thermal degradation and dielectric properties of poly[2-hydroxy,3-(1-naphthyloxy)propyl methacrylate]

et al. 2016

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2-Hydroxy-3-(1-naphthyloxy)propyl methacrylate (NOPMA) monomer was synthesized from reaction of 2-[(2-naphthyloxy)methyl]oxirane with methacrylic acid in the presence of pyridine. The polymerization of NOPMA was carried out by free radical polymerization method in the presence of AIBN at 60°C. The structure of monomer and polymer was characterized by 1 H-NMR, 13 C-NMR and FT-IR spectroscopy techniques. The glass transition temperature and averagemolecular weights of poly(NOPMA) were measured using differential scanning calorimetry and gel permeation chromatography, respectively. The thermal degradation behavior of poly(NOPMA) has been investigated by FT-IR studies of the partially degraded polymer and thermogravimetry. The cold ring fractions (CRFs) were collected at two different temperatures, initially fraction-1 (CRF 1 ) is from room temperature to 320°C, and the other fraction-2 (CRF 2 ) is from 320 to 500°C. The volatile products of the degradation were trapped at -195°C (in liquid nitrogen). All the fractions were characterized by FT-IR, 1 H and 13 C-NMR spectroscopic techniques, and the cold ring fractions (CRFs) were also characterized by GC-MS. For the degradation of polymer, the major compound between products of CRFs is a-naphthol. The GC-MS, FT-IR and NMR data showed that depolymerization corresponding to monomer was not prominent below 320°C in the thermal degradation of poly(NOPMA). The mode of thermal degradation containing formation of the major products was identified. The dielectric permittivity (e 0 ), the loss factor (e 00 ) and conductivity (r ac ) were measured using a dielectric analyzer in the frequency range of 50 Hz to 20 kHz.

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Thermal degradation of poly(methyl methacrylate). 4. Random side-group scission

Cited by 203 publications

References 5 publications

Thermolysis of RAFT-Synthesized Poly(Methyl Methacrylate)

Thermolysis of RAFT-Synthesized Poly(Methyl Methacrylate)

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

Synthesis, thermal degradation and dielectric properties of poly[2-hydroxy,3-(1-naphthyloxy)propyl methacrylate]

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