Enhancement of Mechanical Properties of Cork Through Thermal High-Temperature Treatment (THT) and Boiling

  • T. KermezliEmail author
  • M. Douani
  • M. Announ
Research Article - Mechanical Engineering


The ecological treatment of cork, at high temperature brings about some changes in its mechanical and chemical properties, which make cork a new material with different types of performance (thermal, mass, acoustic and vibratory). For this purpose, our study focuses on determining the optimal thermal cycle by using TGA and IR analyses. In terms of mass insulation, the calculation of the diffusion coefficient, which is a potential indicator of cork improvement, is carried out using new experimental protocols that consist of high-temperature treatment (THT) in addition to boiling. The obtained results show that the lowest value of the apparent diffusion coefficient of cork (Dapp) is reached when the thermal high-temperature treatment (THT) is preceded by boiling and when the heat rate is \(0.5\,{^{\circ }}\hbox {C/mn}\). The average value of Dapp is determined through the calibration of theoretical model with the experimental data collected by utilising conductimetric measures. Using the Bat-Algorithm, the Dapp is determined accurately with a relative error of \(10^{-7}\). Furthermore, the Dapp value is affected by the heat rate during the treatment cycle.


Cork Heat rate of THT cycle Boiling Diffusion model Optimization TGA IR 

List of symbols


KCl mass concentration (g/l)

\((c_{t})_{\mathrm{exp} }\)

Instantaneous concentration of KCl measured by the meter (mM)

\(C_{\infty }\)

Concentration of KCl in the solution after an infinite time (mM)

\(D_{\mathrm{A} }\)

Effective diffusivity of KCl (\(\hbox {m}^{2}/\hbox {s})\)

\((D_{\mathrm{app}})_{\mathrm{A} }\)

Apparent diffusion coefficient of cork sample A

\(D_{\mathrm{A}_{0.5^{\circ }\mathrm{C}} } \)

Apparent diffusion coefficient of cork samples A with \(0.5\,{^{\circ }}\hbox {C/min}\) of rate heat \((\hbox {m}^{2}/\hbox {s})\)

\(D_j^0 \)

Self-diffusion coefficient of ion j


Faraday constant (C)


Half thickness of sample (m)


Molar mass of solute (g/mol)

\(m_{\mathrm{KCl} }\)

Mass of KCl (g)

\((m_{t})_{\mathrm{exp} }\)

Mass of the substance released experimentally at time t (g)

\(m_{\infty }\)

Mass transferred after total desorption after an infinite time (g)


Ideal gas constant (J/mol K)

\(v_{\mathrm{sol} }\)

Volume of the liquid solution immersing the object

\(V_{\mathrm{W} }\)

Volume of water (l)

\(\left| {Z_j } \right| \)

Absolute value of the charge of ion j

\(\sigma _{\mathrm{c}_t } \)

Instantaneous corrected conductivity (S/m)

\(\lambda _j^0 \)

Equivalent conductivity limits diffusion of ion j in water at \(25\,{^{\circ }}\hbox {C}\)

\(\varepsilon \)


\(\tau \)






Potassium chloride




High-temperature treatment




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The authors would like to express their sincere gratitude to the director of the Military Academy Polytechnic for giving us permission to conduct high-temperature treatment experiments in mechanical engineering laboratory.


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Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  1. 1.LCVVE, Faculty of TechnologyUniversity Hassiba BenboualiChlefAlgeria
  2. 2.LME, Faculty of TechnologyUniversité Yahia Fares de MédéaMédéaAlgeria

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