Characteristics and Kinetics of Cellulose Degradation in Oil-Impregnated Pressboard under Simultaneous Thermal-Electrical-Mechanical Stress Accelerated Aging

Abstract In the present work, the artificial aging kinetics of SiCp particles reinforced AA7075-SiCp composite fabricated by stir casting method was investigated. The aging behavior of AA7075-SiCp composite was investigated by Rockwell hardness tests and differential scanning calorimetry (DSC). Results show there are no changes in the sequences of formation and dissolution of precipitate. Reinforced particles are uniformly distributed throughout the matrix. The hardness profile shows increase in hardness with the comparison of AA7075 base alloy. In addition to SiCp in the matrix, precipitation kinetics has changed compared with base alloy since higher dislocations present in composite, hence requires lower activation energy to form ή precipitate and takes less time to reach the maximum hardness. In contrast, the addition of SiCp at low volume percent also showing accelerated aging phenomena in the composite during the aging process. High-resolution transmission electron microscope (HRTEM) micrograph of peak age (T6) condition divulges that enormous fine and plate-like ή (MgZn2) precipitates are uniformly distributed in the composite.

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Effect of Mechanical Stress on the Kinetics of Heterogeneous Electron Transfer

Langmuir ◽

10.1021/la801009f ◽

2008 ◽

Vol 24 (18) ◽

pp. 9941-9944 ◽

Cited By ~ 21

Author(s):

Peng Sun ◽

Zhen Liu ◽

Honghui Yu ◽

Michael V. Mirkin

Keyword(s):

Electron Transfer ◽

Mechanical Stress ◽

Heterogeneous Electron Transfer ◽

Kinetics Of

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Thermal Properties of Multilayer Nanocomposites Based on Halloysite Nanotubes and Biopolymers

Journal of Composites Science ◽

10.3390/jcs2030041 ◽

2018 ◽

Vol 2 (3) ◽

pp. 41 ◽

Cited By ~ 11

Author(s):

Vanessa Bertolino ◽

Giuseppe Cavallaro ◽

Stefana Milioto ◽

Filippo Parisi ◽

Giuseppe Lazzara

Keyword(s):

Thermal Properties ◽

Cellulose Degradation ◽

Oxidative Degradation ◽

Middle Layer ◽

Halloysite Nanotubes ◽

Hydroxypropyl Cellulose ◽

Inert Atmosphere ◽

Scanning Calorimetry ◽

Dsc Studies ◽

Kinetics Of

This paper reports a novel procedure to fabricate multilayer composite biofilms based on halloysite nanotubes (HNTs) and sustainable polymers. Among the biopolymers, the non-ionic (hydroxypropyl cellulose) and cationic (chitosan) molecules were selected. The nanocomposites were prepared by the sequential casting of ethanol solutions of hydroxypropyl cellulose and aqueous dispersions of chitosan/HNTs. The composition of the bio-nanocomposites was systematically changed in order to investigate the effect of the hydroxypropyl cellulose/HNTs ratio on the thermal properties of the films, which were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). DSC studies were conducted in the static air (oxidative atmosphere), while TG measurements were carried out under nitrogen flow (inert atmosphere). The analysis of DSC data provided the enthalpy and the temperature for the oxidative degradation of the bio-nanocomposites. These results were helpful to estimate the efficacy of the well-compacted middle layer of HNTs as a flame retardant. TG experiments were performed at a variable heating rate and the collected data were analyzed by the Friedman’s method (non-isothermal thermogravimetric approach) with the aim of studying the kinetics of the hydroxypropyl cellulose degradation in the multilayer nanocomposites. This work represents an advanced contribution for designing novel sustainable nanocomposites with excellent thermal behavior as a consequence of their peculiar multilayer structure.

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Investigation in the kinetics of thermal and thermo-oxidative degradation of wood treated with fire-retardants and untreated wood

Pozharnaia bezopasnost` ◽

10.37657/vniipo.pb.2020.72.48.002 ◽

2020 ◽

pp. 24-29

Author(s):

Николай Петрович Копылов ◽

Александр Евгеньевич Кузнецов ◽

Елена Юрьевна Сушкина ◽

Владимир Васильевич Яшин

Keyword(s):

Forest Fires ◽

Flame Retardants ◽

Degradation Products ◽

Cellulose Degradation ◽

Oxidative Degradation ◽

Fire Retardant ◽

Untreated Wood ◽

Fire Retardants ◽

Kinetics Of ◽

Thermo Oxidative Degradation

Разработана экспериментальная методика определения механизма огнезащитного действия антипиренов на основе изучения кинетики термической и термоокислительной деструкции древесины. Отработка методики проведена на антипирене MgCl (бишофит). Методика основывается на количественной оценке при термическом разложении древесины выхода продуктов деструкции: CO, CO, дымового аэрозоля. В качестве приборной базы используются хроматографы, фотометр фотоэлектрический для аэрозолей, спектрофотометр. Water with various additives is used during extinguishing forest fires. Fire-retardants are used as additives in most cases. The selection of fire-retardants depends on the level of increase in extinguishing effectiveness at their addition to water. The purpose of this work is to develop an experimental method for evaluating the fireproof effect of flame retardants solutions. This method is based on the investigation of the kinetics of thermal and thermo-oxidative degradation of treated wood with flame retardants and untreated wood. In practice, bischofite and diammonium phosphate are often used as additives. Investigations were conducted using MgCl (bischofite). The explanation of the fireproof effect of the bischofite solution is based on the study of the yield of decomposition products (CO, CO, smoke aerosol) of wood treated with fire-retardant and untreated wood. The instrument base includes chromatographs «Gasochrom 3101», «Tsvet 152», photoelectric photometer for aerosols, spectrophotometer IKS-29. Wood samples were subjected to thermal and thermo-oxidative degradation in nitrogen flow or air flow with a volume velocity of 60 ml · min. Pulse heating in the pyrolysis furnace was carried out in the temperature range from 350 to 550 °C. The significant increase in fire resistance of wood treated with fire-retardant was found as a result of researches using the proposed method. It was shown that the theory of the coating layer, thermal and gas theory of catalytic dehydration are not suitable for explaining the mechanism of fireproof action of an aqueous solution of magnesium halides. Although it is not excluded the inhibition of gas-phase oxidation of cellulose degradation products by hydrogen halides released when heating aqueous solutions of magnesium halides.

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On the kinetics of cellulose degradation: looking beyond the pseudo zero order rate equation

Cellulose ◽

10.1007/s10570-007-9162-8 ◽

2007 ◽

Vol 15 (2) ◽

pp. 193-203 ◽

Cited By ~ 81

Author(s):

Paolo Calvini ◽

Andrea Gorassini ◽

Antonio Luigi Merlani

Keyword(s):

Rate Equation ◽

Cellulose Degradation ◽

Zero Order ◽

Order Rate ◽

Kinetics Of ◽

Order Rate Equation

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Effect of mechanical stress on kinetics of degradation of marine coatings

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2008.05.001 ◽

2008 ◽

Vol 63 (3) ◽

pp. 316-322 ◽

Cited By ~ 32

Author(s):

N. Fredj ◽

S. Cohendoz ◽

X. Feaugas ◽

S. Touzain

Keyword(s):

Mechanical Stress ◽

Marine Coatings ◽

Kinetics Of Degradation ◽

Kinetics Of

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Hydrolysis kinetics of ATBS polymers at elevated temperature, via 13 C NMR spectroscopy, as basis for accelerated aging tests

Journal of Petroleum Science and Engineering ◽

10.1016/j.petrol.2017.09.013 ◽

2017 ◽

Vol 158 ◽

pp. 680-692 ◽

Cited By ~ 6

Author(s):

K. Sandengen ◽

H.C. Widerøe ◽

L. Nurmi ◽

S. Hanski

Keyword(s):

Elevated Temperature ◽

Nmr Spectroscopy ◽

Accelerated Aging ◽

Hydrolysis Kinetics ◽

Kinetics Of ◽

C Nmr

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Simulation and Analysis for Composite Casing Aging Trend Based on ANSYS

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.668-669.248 ◽

2014 ◽

Vol 668-669 ◽

pp. 248-252

Author(s):

Ying Liang ◽

Chun Yan Cui

Keyword(s):

Mechanical Stress ◽

Accelerated Aging ◽

Force Factor ◽

Aging Research ◽

Element Analysis ◽

Aging Trend ◽

Accelerated Aging Test ◽

Aging Test ◽

Rubber Composite

According to the aging characteristics of composite casing, we have established the composite bushing model of different radius with the ANSYS finite element analysis software, and analyzed the defects in different forms and the action under different mechanical stress. At the same time, we have studied the aging trend of composite casing and compared with the similarities and differences between the aging of composite insulators. The result showed that under the mechanical stress the bigger than the smaller aging deformation was more serious, and the defect forms had no obvious influence on the development of aging. Thus, the composite casing artificial accelerated aging test should increase the role of mechanical force factor, while the composite insulator aging research methods and conclusions should also increase the qualification when applied to silicone rubber composite casing.

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Spatial and temporal translocation of PKCα in single endothelial cell in response to focal mechanical stimulus

10.1101/191833 ◽

2017 ◽

Author(s):

Masataka Aarai ◽

Toshihiro Sera ◽

Takumi Hasegawa ◽

Susumu Kudo

Keyword(s):

Endothelial Cells ◽

Endoplasmic Reticulum ◽

Endothelial Cell ◽

Mechanical Stress ◽

Mechanical Stimulus ◽

The Other ◽

Protein Kinase Cα ◽

Intracellular Ca ◽

Summary Statement ◽

Kinetics Of

AbstractWe observed the kinetics of protein kinase Cα (PKCα) and the intracellular Ca2+ wave in endothelial cells (ECs) in response to microscopic mechanical stress to investigate the effect of mechanical stress on PKCα translocation. The results show that a focal mechanical stimulus induced biphasic and directional PKCα translocation; PKCα initially translocated toward distinct spots near or at the membrane and then accumulated at the stimulus point. The low initial translocation occurred simultaneously in parallel with the increase in Ca2+. Initial translocation was inhibited in spite of Ca2+ increase when the diacylglycerol (DAG) binding domain of PKCα was inhibited, suggesting that translocation requires intracellular Ca2+ increase and DAG. On the other hand, high secondary translocation was delayed, occurring after the Ca2+ wave; however, this secondary translocation occurred even when Ca2+ release from the endoplasmic reticulum was inhibited, while it did not occur when the mechanosensitive (MS) channel was inhibited. These results indicated that at least Ca2+ influx through MS channels is required. Our results support the implication of PKCα in the Ca2+ signaling pathway in response to mechanical stress in ECs.Summary statementIn response to a focal mechanical stimulus, PKCα in an endothelial cell was initially translocated toward distinct spots near or at the membrane and then accumulated at the stimulus point.

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