Studies on the Photodegradation of Poly(Methyl Methacrylate),

Abouelezz, Mohamed; Waters, P. F.

doi:10.21236/ada304535

Cited by 4 publications

(5 citation statements)

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“…Figure 4 presents the UV-Vis spectra of the three types of transparent samples before artificial aging. It is known that pure PMMA absorbs mainly wavelengths <260 nm [ 15 , 16 , 17 , 18 , 19 , 20 , 55 ], but thick samples may present absorption until 300 nm due to the accumulation of chromophores, present in the polymer matrix as consequence of processing [ 19 ]. This is probably the case of TPL; however, the additional absorption at 300–400 nm observed in the UV-Vis spectra of TPS and TPA samples is most probably associated with the presence of additives.…”

Section: Resultsmentioning

confidence: 99%

“…The main aging mechanism of PMMA, photooxidation, has been extensively studied [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The photodegradation mechanism of methacrylic and acrylic polymers has been followed by size exclusion chromatography and a distinction in behavior has been observed [ 22 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

“…In both, scission and crosslinking are present, with scission being the dominant mechanism in acrylics, whereas in methacrylics crosslinking may compete depending on the volume of the side group, and it is therefore residual in PMMA (the methacrylic with the smallest side group, a methyl). Films and sheets of PMMA should absorb bellow 260 nm [ 13 , 15 , 16 , 17 , 18 , 19 , 20 ]; however, chromophores such as hydroperoxide groups are usually present in the polymer matrix as consequence of synthesis and processing, which may absorb radiation at wavelengths higher than the polymer and initiate photodegradation reactions [ 26 ]. The singularity of the stability of PMMA may be further explained by the fact that, to obtain the excellent optical properties typical of an acrylic sheet, the level of impurities must be extremely low [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

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Characterization and Long-Term Stability of Historical PMMA: Impact of Additives and Acrylic Sheet Industrial Production Processes

et al. 2020

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This work aims at understanding the influence of the production processes and materials in the properties and long term behavior of acrylic sheet, i.e., poly(methyl methacrylate) (PMMA), a material generally considered very stable in museum collections. A comparative study was conducted in samples from cast acrylic sheets produced in the early 2000s, from which manufacturing details were known, and samples provided by the artist Lourdes Castro from acrylic sheets she had bought in the 1960s. Transparent and red opaque cast acrylic samples, containing cadmium red pigment, were used. All samples were artificially aged in a solarbox with irradiation λ > 300 nm for a total period of 8000 h, and alterations were followed by a multi-analytical approach which included Raman, infrared (FTIR-ATR) and UV-Vis spectroscopies; gravimetry; size exclusion chromatography (SEC); thermogravimetry (TGA); micro-indentation; colorimetry; and optical microscopy. Not all cast PMMA sheets presented similar stabilities. We have concluded that the production processes (which may include the polymerization conditions, the organic additives and the origin of the monomer) play a more important role in the properties and long-term behavior of these acrylic sheets than the presence of cadmium red and/or the age of the material.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization and Long-Term Stability of Historical PMMA: Impact of Additives and Acrylic Sheet Industrial Production Processes

et al. 2020

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“…Figure 4 suggests processes such as the outward diffusion of gaseous species or the depletion of residual components, e.g., additives. Mass loss up to 4.35% was observed in a previous study [14], where other characteristics (observed using gel permeation chromatography and thermal mechanical analysis) indicated chain scission. The similar mass loss observed for both unaged and veteran specimens suggests material degradation, i.e., a similar rate of depletion of residual components between specimens of such different history is unlikely.…”

Section: Additional Results: Yellowness Index Mass Loss and Data Summarymentioning

confidence: 55%

Durability of poly(methyl methacrylate) lenses used in concentrating photovoltaic modules

Miller

Gedvilas

et al. 2010

SPIE Proceedings

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Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens-and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

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“…Full scans over the ultraviolet and visible spectra were made from 220 to 800 nm for highly-transparent pure PMMA samples using a Shimadzu UV-3600 spectrophotometer. The results show that the absorbance peak in the ultraviolet region for pure PMMA was at 226 nm, which represents the UV damage threshold for the polymer [18,19,20], whilst the transmittance peak in the visible region for pure PMMA was 798 nm. The transmittance peak indicates the actual performance for pure PMMA [19].…”

Section: Methodsmentioning

confidence: 99%

Transparent Blend of Poly(Methylmethacrylate)/Cellulose Acetate Butyrate for the Protection from Ultraviolet

et al. 2016

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Abstract:The use of transparent polymers as an alternative to glass has become widespread. However, the direct exposure of these materials to climatic conditions of sunlight and heat decrease the lifetime cost of these products. The aim of this study was to minimize the harm caused by ultraviolet (UV) radiation exposure to transparent poly(methylmethacrylate) (PMMA), which usually leads to changes in the physical and chemical properties of these materials and reduced performance. This was achieved using environmentally friendly cellulose acetate butyrate (CAB). The optical, morphological, and thermal properties of CAB blended with transparent PMMA was studied using UV-VIS spectrophotometry, scanning electron microscopy, X-ray diffraction, dynamic mechanical analysis, and thermal gravimetric analysis. The results show that CAB was able to reduce the effects of UV radiation by making PMMA more transparent to UV light, thereby preventing the negative effects of trapped radiation within the compositional structure, while maintaining the amorphous structure of the blend. The results also show that CAB blended with PMMA led to some properties commensurate with the requirements of research in terms of a slight increase in the value of the modulus and the glass transition temperature for the PMMA/CAB blend.

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Studies on the Photodegradation of Poly(Methyl Methacrylate),

Cited by 4 publications

References 0 publications

Characterization and Long-Term Stability of Historical PMMA: Impact of Additives and Acrylic Sheet Industrial Production Processes

Characterization and Long-Term Stability of Historical PMMA: Impact of Additives and Acrylic Sheet Industrial Production Processes

Durability of poly(methyl methacrylate) lenses used in concentrating photovoltaic modules

Transparent Blend of Poly(Methylmethacrylate)/Cellulose Acetate Butyrate for the Protection from Ultraviolet

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