Thermal Decomposition of Vermiculites: Kinetics of Dehydration and Dehydroxylation Processes

Adhikari, M.; Majumdar, M. K.; Pati, A. K.

doi:10.1080/0371750x.1983.10822648

Cited by 3 publications

(3 citation statements)

References 8 publications

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“…Dehydroxylation, elimination of water from hydroxyl groups, is an important thermal dissociation reaction among those occurring in the kaolinite group minerals and in natural or synthesized silicate materials [19]. Non-isothermal kinetics of this process, which occurs at temperature quite higher than dehydration due to the presence of stronger hydrogen bonds between the OH groups, was extensively studied for different types of KAOs [18,[20][21][22][23][24][25][26], but little is known about the same process occurring in HNTs where early papers used questionable methods under isothermal conditions [27,28].…”

Section: Introductionmentioning

confidence: 99%

Thermal behavior study of pristine and modified halloysite nanotubes

Duce

Ciprioti

Ghezzi

et al. 2015

J Therm Anal Calorim

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Pristine halloysite nanotubes (HNTs) were studied by thermogravimetry (TG) up to 800°C. Etching of alumina from inside the tube (causing a significant increase in tube lumen) was realized by treating the material with an acidic H 2 SO 4 solution at 50°C. Both materials were characterized by TG-FTIR techniques and their thermal behaviors were compared with that of kaolinite. The coupling of TG with FTIR enables to detect the gases evolved during the TG experiments, thus confirming that only pristine HNTs undergo dehydration with the loss of interlayer water molecules at around 245°C, while dehydroxylation occurs in all these materials in close temperature ranges around 500°C. TG runs at five different heating rates (2, 5, 10, 15 and 20°C min -1 ), was carried out in the same experimental conditions used for the thermal analysis study with the aim to investigate dehydration and dehydroxylation kinetics using some isoconversional methods recommended by the ICTAC kinetic committee, and thermogravimetric data under a modulated rising temperature program. Finally, the results of the kinetic analysis were discussed and explained in terms of the strengths of the hydrogen bonds broken during these processes.

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Section: Introductionmentioning

confidence: 99%

Thermal behavior study of pristine and modified halloysite nanotubes

Duce

Ciprioti

Ghezzi

et al. 2015

J Therm Anal Calorim

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“…It is also worth noting that the m LOSS,250 °C values of the three friction materials exceed the 7% value, indicating that other constituents of the friction materials over the resins (e.g. rubber, aramid fibre, vermiculite and mica [54,55]) are also degrading.…”

Section: Air Atmospherementioning

confidence: 96%

“…The mass loss can be explained by the degradation of other ingredients present in the friction material mixture, e.g. vermiculite, graphite and coke [54,56,57], which also contribute to the maximum mass loss rate in the case of R6_fm and R7_fm. The mass increase observed above 800 °C is related to the oxidation of metallic constituents present in the friction material like Fe fibres.…”

Section: Friction Materials In Air Atmospherementioning

confidence: 99%

Characterization of benzoxazine resins for brake pad friction materials manufacturing

Carlevaris

Menapace

Straffelini

et al. 2022

J Therm Anal Calorim

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Phenolic resins are the most commonly used binders in brake pads for automotive disc brake systems owing to their affordability and thermal properties. However, they also show some limitations related to their crosslinking mechanism. Benzoxazine resins present themselves as possible alternatives for this application by providing enhanced thermal properties as well as other industrially attractive characteristics such as lower moisture absorption and unlimited shelf life. This study investigates the thermal properties of two different benzoxazine resins, with the aim of assessing their capabilities as binder for brake pad and of understanding how to process them in order to actually employ them as such. DSC, TGA, hardness and tribological analyses were carried out on neat resin samples and on friction materials containing them as binder. The presence of several concurring reactions was detected during the crosslinking reaction of benzoxazine resins. The benzoxazine resins showed lower mass loss respect to a phenolic resin in the temperature range of interest for commercial brake pads application. Friction material containing benzoxazine resin binder showed promising tribological results.

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