Relationship between the conditions of pyrolysis and the structural and chemical transformation of cellulose hydrate

Biryukova, G.P.; Shablygin, M. V.; Mikhailov, N. V.; Андрианов, К. А.

doi:10.1016/0032-3950(73)90179-2

Cited by 8 publications

(7 citation statements)

References 1 publication

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“…However, some defects cannot be annealed even at very high temperatures, causing the material to remain non-graphitizing with its characteristic low density. The exact temperature of each pyrolytic transition, as well as the backbone structure are dependent on the chemical structure of the precursor polymer, and the collective rate of various parallel thermochemical reactions taking place within the pyrolyzing material 38 , 42 , 43 . Evidently, the formation and collapse of intermediate structures during pyrolysis can provide important cues on the resulting organization of the graphene fragments.…”

Section: Introductionmentioning

confidence: 99%

“…One reason for this ambiguity is that glassy carbon is not a unique material. Its exact microstructure is known to be influenced by pyrolysis conditions, 12,35,36 chemical composition of the precursor polymer 37 and in the case of nano-scale structures, the forces applied during polymer-patterning. 8 Pyrolysis encompasses thermochemical decomposition of polymers.…”

mentioning

confidence: 99%

“…The exact temperature of each pyrolytic transition, as well as the backbone structure are dependent on the chemical structure of the precursor polymer, and the collective rate of various parallel thermochemical reactions taking place within the pyrolyzing material. 36,40,41 Evidently, the formation and collapse of intermediate structures during pyrolysis can provide important cues on the resulting organization of the graphene fragments. Some such intermediates are short-lived or undergo major reconfiguration on cooling.…”

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confidence: 99%

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Evolution of Glassy Carbon Microstructure: In Situ Transmission Electron Microscopy of the Pyrolysis Process

Sharma

Kumar

Korvink

et al. 2018

Sci Rep

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Glassy carbon is a graphene-rich form of elemental carbon obtained from pyrolysis of polymers, which is composed of three-dimensionally arranged, curved graphene fragments alongside fractions of disordered carbon and voids. Pyrolysis encompasses gradual heating of polymers at ≥ 900 °C under inert atmosphere, followed by cooling to room temperature. Here we report on an experimental method to perform in situ high-resolution transmission electron microscopy (HR-TEM) for the direct visualization of microstructural evolution in a pyrolyzing polymer in the 500–1200 °C temperature range. The results are compared with the existing microstructural models of glassy carbon. Reported experiments are performed at 80 kV acceleration voltage using MEMS-based heating chips as sample substrates to minimize any undesired beam-damage or sample preparation induced transformations. The outcome suggests that the geometry, expansion and atomic arrangement within the resulting graphene fragments constantly change, and that the intermediate structures provide important cues on the evolution of glassy carbon. A complete understanding of the pyrolysis process will allow for a general process tuning specific to the precursor polymer for obtaining glassy carbon with pre-defined properties.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Evolution of Glassy Carbon Microstructure: In Situ Transmission Electron Microscopy of the Pyrolysis Process

Sharma

Kumar

Korvink

et al. 2018

Sci Rep

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“…If the pyrolysis product (mixture of all intermediate materials at any given temperature) goes through a semi-solid (rubbery) phase, owing to the fact that its T g falls just below the process temperature [ 21 , 66 ], this phenomenon is known as coking [ 25 ]. The Scanning Electron Microscope (SEM) image in the bottom-left of Figure 1 represents a carbonized structure where a fiber was intentionally suspended onto an array of hollow micropillars (pillar diameter: ~5x fiber thickness; all structures fabricated in SU-8 [ 65 ]).…”

Section: Polymer-derived Carbonmentioning

confidence: 99%

Glassy Carbon: A Promising Material for Micro- and Nanomanufacturing

Sharma

2018

Materials

117

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When certain polymers are heat-treated beyond their degradation temperature in the absence of oxygen, they pass through a semi-solid phase, followed by the loss of heteroatoms and the formation of a solid carbon material composed of a three-dimensional graphenic network, known as glassy (or glass-like) carbon. The thermochemical decomposition of polymers, or generally of any organic material, is defined as pyrolysis. Glassy carbon is used in various large-scale industrial applications and has proven its versatility in miniaturized devices. In this article, micro and nano-scale glassy carbon devices manufactured by (i) pyrolysis of specialized pre-patterned polymers and (ii) direct machining or etching of glassy carbon, with their respective applications, are reviewed. The prospects of the use of glassy carbon in the next-generation devices based on the material’s history and development, distinct features compared to other elemental carbon forms, and some large-scale processes that paved the way to the state-of-the-art, are evaluated. Selected support techniques such as the methods used for surface modification, and major characterization tools are briefly discussed. Barring historical aspects, this review mainly covers the advances in glassy carbon device research from the last five years (2013–2018). The goal is to provide a common platform to carbon material scientists, micro/nanomanufacturing experts, and microsystem engineers to stimulate glassy carbon device research.

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“…For example, a large fraction of unsaturated bonds, a non-carbon backbone, inability to form a sufficient number of C–C bonds during heat-treatment, or an abundance of oxygen or halide atoms in a polymer, may lead to an unsuccessful pyrolysis resulting in a distorted or porous structure, or an extremely low carbon yield [ 14 ]. During pyrolysis, the morphology of a structure can only be preserved if the glass transition temperature

of the carbonizing matrix increases faster than the rate of the chemical reactions responsible for polymer’s thermal transformation [ 18 , 19 , 20 ]. In other words, if at any given point during pyrolysis the material experiences a temperature above its glass transition temperature, it will go though a rubbery state and will lose its pre-patterned shape [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Custom-Designed Glassy Carbon Tips for Atomic Force Microscopy

et al. 2017

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Glassy carbon is a graphenic form of elemental carbon obtained from pyrolysis of carbon-rich precursor polymers that can be patterned using various lithographic techniques. It is electrically and thermally conductive, mechanically strong, light, corrosion resistant and easy to functionalize. These properties render it very suitable for Carbon-microelectromechanical systems (Carbon-MEMS) and nanoelectromechanical systems (Carbon-NEMS) applications. Here we report on the fabrication and characterization of fully operational, microfabricated glassy carbon nano-tips for Atomic Force Microscopy (AFM). These tips are 3D-printed on to micro-machined silicon cantilevers by Two-Photon Polymerization (2PP) of acrylate-based photopolymers (commercially known as IP-series resists), followed by their carbonization employing controlled pyrolysis, which shrinks the patterned structure by ≥98% in volume. Tip performance and robustness during contact and dynamic AFM modes are validated by morphology and wear tests. The design and pyrolysis process optimization performed for this work indicate which parameters require special attention when IP-series polymers are used for the fabrication of Carbon-MEMS and NEMS. Microstructural characterization of the resulting material confirms that it features a frozen percolated network of graphene sheets accompanied by disordered carbon and voids, similar to typical glassy carbons. The presented facile fabrication method can be employed for obtaining a variety of 3D glassy carbon nanostructures starting from the stereolithographic designs provided by the user.

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Relationship between the conditions of pyrolysis and the structural and chemical transformation of cellulose hydrate

Cited by 8 publications

References 1 publication

Evolution of Glassy Carbon Microstructure: In Situ Transmission Electron Microscopy of the Pyrolysis Process

Evolution of Glassy Carbon Microstructure: In Situ Transmission Electron Microscopy of the Pyrolysis Process

Glassy Carbon: A Promising Material for Micro- and Nanomanufacturing

Custom-Designed Glassy Carbon Tips for Atomic Force Microscopy

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