Controlled thermal degradation of polystyrene leading to selective formation of end-reactive oligomers

Sawaguchi, Takashi; Senō, Manabu

doi:10.1002/(sici)1099-0518(19980115)36:1<209::aid-pola26>3.0.co;2-m

Cited by 18 publications

(3 citation statements)

References 8 publications

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“…Further, the rate of decomposition and the products of the decomposition process for such polymers are strongly temperature dependent. For example, although the decomposition of polystyrene in a vacuum peaks at 450 °C, the process can begin at below 300 °C (14) and the decomposition may favor the formation of higher vapor pressure oligomers at the lowest temperatures (18).…”

Section: What Are the Particles?mentioning

confidence: 99%

An Investigation into the Characteristics and Formation Mechanisms of Particles Originating from the Operation of Laser Printers

Morawska

Johnson

et al. 2009

Environ. Sci. Technol.

133

129

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While current research has demonstrated that the operation of some laser printers results in emission of high concentrations of ultrafine particles, fundamental gaps in knowledge in relation to the emissions still remain. In particular, there have been no answers provided to questions such as the following: (1) What is the composition of the particles? (2) What are their formation mechanisms? (3) Why are some printers high emitters, while others are low? Considering the widespread use of printers and human exposure to these particles, understanding the process of particle formation is of critical importance. This study, using state-of-the-art instrumental methods, has addressed these three points. We present experimental evidence that indicates that intense bursts of particles are associated with temperature fluctuations and suggest that the difference between high and low emitters lies in the speed and sophistication of the temperature control. We have also shown, for the first time, that the particles are volatile and are of secondary nature, being formed in the air from VOC originating from both the paper and hot toner. Some of the toner is initially deposited on the fuser roller, after which the organic compounds evaporate and then form particles, through one of two main reaction pathways: homogeneous nucleation or secondary particle formation involving ozone.

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Section: What Are the Particles?mentioning

confidence: 99%

An Investigation into the Characteristics and Formation Mechanisms of Particles Originating from the Operation of Laser Printers

Morawska

Johnson

et al. 2009

Environ. Sci. Technol.

133

129

View full text Add to dashboard Cite

show abstract

“…1 Nevertheless, the carbon−carbon bonds that comprise the backbone of PS contribute to its environmental persistence and limit its opportunities for chemical recycling or upcycling. While PS thermoplastics can sometimes be dissolved for reprocessing, converted to styrene when heated above their ceiling temperature, 2 or engineered to thermally degrade into low molar mass fragments, 3 such processes are often energy-intensive, yield complex product mixtures, may not address environmental persistence, and do not apply to all forms of PS (e.g., copolymers, especially crosslinked variants) and other vinyl polymers.…”

Section: ■ Introductionmentioning

confidence: 99%

Cleavable Comonomers for Chemically Recyclable Polystyrene: A General Approach to Vinyl Polymer Circularity

et al. 2022

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Many common polymers, especially vinyl polymers, are inherently difficult to chemically recycle and are environmentally persistent. The introduction of low levels of cleavable comonomer additives into existing vinyl polymerization processes could facilitate the production of chemically deconstructable and recyclable variants with otherwise equivalent properties. Here, we report thionolactones that serve as cleavable comonomer additives for the chemical deconstruction and recycling of vinyl polymers prepared through free radical polymerization, using polystyrene (PS) as a model example. Deconstructable PS of different molar masses (∼20−300 kDa) bearing varied amounts of statistically incorporated thioester backbone linkages (2.5−55 mol %) can be selectively depolymerized to yield well-defined thiol-terminated fragments (<10 kDa) that are suitable for oxidative repolymerization to generate recycled PS of nearly identical molar mass to the parent material, in good yields (80−95%). A theoretical model is provided to generalize this molar mass memory effect. Notably, the thermomechanical properties of deconstructable PS bearing 2.5 mol % of cleavable linkages and its recycled product are similar to those of virgin PS. The additives were also shown to be effective for deconstruction of a cross-linked styrenic copolymer and deconstruction and repolymerization of a polyacrylate, suggesting that cleavable comonomers may offer a general approach toward circularity of many vinyl (co)polymers.

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“…5 We prepared multiblock copolymers of IX,w-dihydrosilylpolydimethylsiloxane with these telechelic oligomers with different stereoregularities. 12 The degradation products are produced via various elementary reactions of secondary terminal macro- radicals in the depropagation step, as discussed previously. 5 A possible mechanism for the predominant formation of TVD of nonvolatile oligomers (polymer residue) is as follows: telechelic oligomers are formed by intramolecular hydrogen abstraction (back-biting) of secondary terminal macroradicals followed by f3 scission at the end of main chain and intermolecular hydro-Polym.…”

Section: Res Ul Ts and Discussionmentioning

confidence: 99%

Preparation of Telechelic Oligomers by the Thermal Degradation of Syndiotactic Polypropylene

Sawaguchi

Senō

1996

Polym J

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Controlled thermal degradation of polystyrene leading to selective formation of end-reactive oligomers

Cited by 18 publications

References 8 publications

An Investigation into the Characteristics and Formation Mechanisms of Particles Originating from the Operation of Laser Printers

An Investigation into the Characteristics and Formation Mechanisms of Particles Originating from the Operation of Laser Printers

Cleavable Comonomers for Chemically Recyclable Polystyrene: A General Approach to Vinyl Polymer Circularity

Preparation of Telechelic Oligomers by the Thermal Degradation of Syndiotactic Polypropylene

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