Photosensitized degradation of polystyrene by benzophenone in benzene solution

Mita, Itaru; Takagi, Toshie; Horie, Kazuyuki; Shindo, Yoichi

doi:10.1021/ma00141a011

Cited by 30 publications

(29 citation statements)

References 6 publications

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“…Photoinduced damage in dye-doped polymer matrices has been studied in various systems for different applications [85][86][87][88][89][90][91][92][93][94]. Sensitized photodegradation and photooxidation of polymers can be induced by photoinitiators, in which polymer degradation or oxidation can be initiated by free radicals originating from photodegradation of sensitizers; or by photosensitizers, in which excited sensitizers transfer energy to the polymer or oxygen to initiate photodegradation or photooxidation [85].…”

Section: Introductionmentioning

confidence: 99%

“…Sensitized photodegradation and photooxidation of polymers can be induced by photoinitiators, in which polymer degradation or oxidation can be initiated by free radicals originating from photodegradation of sensitizers; or by photosensitizers, in which excited sensitizers transfer energy to the polymer or oxygen to initiate photodegradation or photooxidation [85]. Studies on photooxidation or photodegradation of various sensitized polymers have been reported including sensitized PS [85][86][87][88] and sensitized PMMA [89,90]. Laser ablation of polymers can be induced with the assistance of photosensitizers using visible lasers at wavelengths of 351 nm [91], 488 nm [92], and 532 nm [93].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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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“…These radicals can combine to form a C‐C bond. The photodegradation of polystyrene when irradiated in air for several hours has been well documented . The photodegradation was reduced by irradiating only for short periods of time (15–30 min).…”

Section: Resultsmentioning

confidence: 99%

“…The photodegradation of polystyrene when irradiated in air for several hours has been well documented. [24][25][26] The photodegradation was reduced by irradiating only for short periods of time (15-30 min). Also, the high concentration of BP directly on top of the PS fi lm can compete with the polymer chain scission and favor BP and PS radical coupling.…”

Section: Resultsmentioning

confidence: 99%

Grafting of a Stimuli Responsive Polymer on Nanolayered Coextruded PS/PCL Films by Surface Initiated Polymerization

Pangilinan

León

Mangadlao

et al. 2016

Macro Materials & Eng

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A simple method of preparing stimuli‐responsive polystyrene (PS)/polycaprolactone (PCL) nanolayered films with by growing poly(N‐isopropylacrylamide) (PNIPAM) brush on the surface by surface‐initiated polymerization is reported. Atom transfer radical polymerization (ATRP) initiator with a benzophenone moiety is attached onto the surface by UV irradiation. After ATRP polymerization, PNIPAM brush films with varying thicknesses are produced. X‐ray photoelectron spectroscopy (XPS) confirms the successful deposition of initiator and grafting of the polymer. Moreover, the behavior of the brush film as a function of temperature is demonstrated by contact angle experiments. Photopatterning is also achieved by using a photomask and is confirmed by Fourier Transform Infrared (FTIR) imaging.

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“…[ 64 ] The radical on PS can then undergo β‐scission to release an α‐alkylstyrene product and form another benzylic radical on PS (Figure 17c). [ 64 ] The radical on PS can also abstract a hydrogen atom from another PS methine position to propagate the radical chain process. [ 64 ] Alternatively, chain termination or crosslinking can occur to stop the PS degradation.…”

Section: Non‐thermal Upcyclingmentioning

confidence: 99%

Upcycling to Sustainably Reuse Plastics

et al. 2021

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The annual production is still growing and is expected to continue, meaning that it is imperative for us to plan for a future that will have even more plastics.Yet, the ubiquity of plastics has been recognized to be a double-edged sword. It was estimated that 8300 Mt of virgin plastics were produced between 1950 to 2015, but 6300 Mt of them had become plastic waste with 79% accumulated in landfills or the natural environment such as the waterways and the ocean. [1a] In 2015 alone, around 302 Mt or 74% of the annual production had become waste, with only 14% recycled, 14% combusted, and the remainder exposed to the environment (Table 1). [2] Over 8 Mt of plastics are believed to be added to the aquatic ecosystems every year since 2010, [3] with samples being discovered in some of the remotest marine ecosystems like the Mariana trench, including some dating as far back as 1957. [4] The increase in ocean plastics has been especially dramatic since the 1990s. [4a] Besides being potentially toxic by compromising the immune system in different organisms, plastics have also been found to disrupt global biogeochemical cycles such as nitrification and denitrification. [5] Furthermore, the enormous volumes of plastics being produced, converted, and disposed have been estimated to contribute almost 1800 Mt of CO 2 -equivalents (CO 2 e) in greenhouse gas (GHG) emissions in 2015, with the majority (61% or 1085 Mt) generated at the production stage, 30% or 535 Mt during conversion, and the remaining 9% or 161 Mt from the end of life disposal (Table 2). [6] Alarmingly, the current trajectory in growth of plastics consumption suggests that around 6500 Mt of CO 2 e in GHG emissions (15% of the global carbon budget) is expected by 2050. [6] In 2020, owing to the COVID-19 pandemic, even more plastic wastes are being generated due to increases in the use of food and other packaging materials, as well as the proliferation of single use disposal face masks. This has resulted in a surge in criminal recycling scams where plastic wastes from Europe and North America are being illegally exported to Asian countries to artificially inflate the recycling rates in the countries of origin. [7] Patently, more sustainable approaches are needed to manage the entire life cycle of plastics from production to end of life.To manage the inexorable growth of plastics production and waste, one strategy can be to adopt a zero waste hierarchy that was proposed by the European Commission's Waste Plastics are now indispensable in daily lives. However, the pollution from plastics is also increasingly becoming a serious environmental issue. Recent years have seen more sustainable approaches and technologies, commonly known as upcycling, to transform plastics into value-added materials and chemical feedstocks. In this review, the latest research on upcycling is presented, with a greater focus on the use of renewable energy as well as the more selective methods to repurpose synthetic polymers. First, thermal upcycling approaches are briefly introduced, inc...

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Photosensitized degradation of polystyrene by benzophenone in benzene solution

Cited by 30 publications

References 6 publications

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

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

Grafting of a Stimuli Responsive Polymer on Nanolayered Coextruded PS/PCL Films by Surface Initiated Polymerization

Upcycling to Sustainably Reuse Plastics

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