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Papers by KARIMA BOUGUERMOUH

Research paper thumbnail of 4D-printed PLA-PETG polymer blends: comprehensive analysis of thermal, mechanical, and shape memory performances

Journal of materials science, Jun 19, 2024

Research paper thumbnail of Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Research paper thumbnail of Synthesis, spectroscopic and mechanical properties of K and (K, Na)- geopolymers based on Algerian clays

Algerian kaolinic clay from Tamazert and two alkalines solutions (potassium silicate and mixed po... more Algerian kaolinic clay from Tamazert and two alkalines solutions (potassium silicate and mixed potassium sodium silicate solutions) whose Si/K and Si/(K+Na) molar ratio of 0.58 and 0.80 respectively are used for the preparation of geopolymers. The raw material calcined at 750°C characterized by XRD and DTA/TG. The results carried out by infrared spectroscopy during the K-geopolymer formation process shows the observation of the displacement of the band located at 980 cm -1 which proves the reorganization of network and consequently the polymerization. It was demonstrated that mechanical properties by compressive strength of (Na,K)-geopolymer are higher than that recorded for Kgeopolymer which are respectively 40 MPa and 16 MPa what allows their use in the field of construction. Received 14 Mar 2016, Revised 09 Oct 2016, Accepted 15 Oct 2016

Research paper thumbnail of Comparison study between K-geopolymer and (Na, K)–geopolymer based on calcined clay from Tamazert (north eastern Algerian)

The term of geopolymer introduced in the 70s by the Professor Davidovits, defines a class of mate... more The term of geopolymer introduced in the 70s by the Professor Davidovits, defines a class of materials obtained by the reaction between aluminosilicate powder and an alkaline solution [1]. Basically, these materials were developed as alternatives to organic polymers. The first applications are therefore found in the field of shipbuilding, resins, protection of wooden structures, adhesives resistant to high temperatures, refractory [2]. Geopolymers are currently of considerable interest because of their good thermal [3], chemical [4] and mechanical properties [2] and their potential for use as a green cementitious binder. The geopolymer are based on the amorphous nature of these materials and the coordination numbers of silicon and aluminum. The aim of this work is the comparison between two geopolymers: K-geopolymer and (Na, K)–geopolymer based on calcined clay at 750°C from Tamazert (north eastern Algerian) actived with alkaline potassium silicate solution and mixed sodium and pota...

Research paper thumbnail of Synthesis of geopolymers based on dredged sediment in calcined and uncalcined states

Materials Letters, 2019

The aim of this work is the synthesis of geopolymers from dredged sediments in calcined and uncal... more The aim of this work is the synthesis of geopolymers from dredged sediments in calcined and uncalcined states. Different amounts of dredged sediments (0, 5, 10, 15 and 20 wt %) were introduced within geopolymers paste. Investigations show that dredging sediments were mainly composed by calcite, muscovite and kaolinite. It was demonstrated that highest compressive strength of 22 M pa and durability in hydrochloric acid solution of the geopolymers were obtained when 15 wt% of calcined dredging sediment were added, this is due to more stable geopolymer matrix. In the other hand, calcination activates dredged sediment by changing its crystallinity into an amorphous structure of higher reactivity in alkaline solution.

Research paper thumbnail of Effect of acid attack on microstructure and composition of metakaolin-based geopolymers: The role of alkaline activator

Journal of Non-Crystalline Solids, 2017

The mineral composition of raw materials and the type of alkali cation plays an important role in... more The mineral composition of raw materials and the type of alkali cation plays an important role in the acidic resistance of geopolymers. This paper focuses on the study of chemical durability in hydrochloric acid of potassium and sodium based geopolymers. The study was carried out on two Algerian kaolins and compared with a kaolin from Charente (France). The acid degradation was studied using X-ray Diffraction, Fourier-Transform Infrared and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy. The samples based on Algerian kaolins seems to have the lowest loss in mass for formulations based on potassium due to the presence of secondary minerals (quartz and muscovite). They could have occupied the pores avoiding the release of alkali cations into the acidic solution. Regarding to sodium geopolymers, the best behavior was observed with the kaolin from Charente, which can be attributed to a more stable aluminosilicate cross-linked polymer structure formed for this material, which was corroborated with the Fourier-Transform Infrared analysis.

Research paper thumbnail of Mechanical and Dielectric Properties of High Temperature Coating Insulators Based on By-Product of Algerian Kaolin

Transactions of the Indian Ceramic Society, 2014

ABSTRACT The main objective of this work is to study the mechanical and dielectric properties of ... more ABSTRACT The main objective of this work is to study the mechanical and dielectric properties of high temperature coating insulators based on the by-product resulted from the raw kaolin treatment; this by-product represents about 21 wt% of the kaolin as commercial products. During sintering, the mineralogical phases are mainly mullite, quartz and vitreous silica besides rutile phase which is identified only at 1200° and 1500°C. The sample porosity decreases from 21% to 16%. Mechanical properties carried out by Young's modulus values are enhanced during calcinations from 54 to 57 GPa. Dielectric properties, in the frequency range of 105-109 Hz, of the samples fired at 1400° and 1500°C show that they can be considered as insulators since they exhibit a high relative permittivity (εexp) varying from 6.95 to 7.89 respectively. These parameters depend on glassy, quartz and mullite phases besides porous structures. Porosity affects considerably both the corrected relative permittivity (εc) considering the large difference between εexp, εc and the dielectric loss of the samples.

Research paper thumbnail of Stabilization of flotation wastes resulting from the treatment of Pb/Zn ore based on geopolymers

Materials Letters, 2018

The objective of this study is the stabilization of two heavy metals Pb and Zn wastes resulting f... more The objective of this study is the stabilization of two heavy metals Pb and Zn wastes resulting from the treatment by flotation of Pb/Zn ore. The Pb/Zn wastes are encapsulated in Na-geopolymer based on Algerian metakaolin. However, various amount (0, 5, 10 and 15 wt %) of wastes are introduced within geopolymers paste. Leaching test show that Lead is untraceable in all levels of waste content up to 15 wt% because lead content of the waste is very low and its presence in the leachate is below the level of detection by Atomic Absorption Spectroscopy. In the other hand, traces of Zinc were detected in the various leaching solutions. The geopolymers 28 days ages and 10 wt% give the better results due to more stable geopolymer matrix. Leaching is increased when 15wt% of waste was added due to limited capacity of geopolymers for the heavy metals and deterioration of the structure.

Research paper thumbnail of 4D-printed PLA-PETG polymer blends: comprehensive analysis of thermal, mechanical, and shape memory performances

Journal of materials science, Jun 19, 2024

Research paper thumbnail of Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Research paper thumbnail of Synthesis, spectroscopic and mechanical properties of K and (K, Na)- geopolymers based on Algerian clays

Algerian kaolinic clay from Tamazert and two alkalines solutions (potassium silicate and mixed po... more Algerian kaolinic clay from Tamazert and two alkalines solutions (potassium silicate and mixed potassium sodium silicate solutions) whose Si/K and Si/(K+Na) molar ratio of 0.58 and 0.80 respectively are used for the preparation of geopolymers. The raw material calcined at 750°C characterized by XRD and DTA/TG. The results carried out by infrared spectroscopy during the K-geopolymer formation process shows the observation of the displacement of the band located at 980 cm -1 which proves the reorganization of network and consequently the polymerization. It was demonstrated that mechanical properties by compressive strength of (Na,K)-geopolymer are higher than that recorded for Kgeopolymer which are respectively 40 MPa and 16 MPa what allows their use in the field of construction. Received 14 Mar 2016, Revised 09 Oct 2016, Accepted 15 Oct 2016

Research paper thumbnail of Comparison study between K-geopolymer and (Na, K)–geopolymer based on calcined clay from Tamazert (north eastern Algerian)

The term of geopolymer introduced in the 70s by the Professor Davidovits, defines a class of mate... more The term of geopolymer introduced in the 70s by the Professor Davidovits, defines a class of materials obtained by the reaction between aluminosilicate powder and an alkaline solution [1]. Basically, these materials were developed as alternatives to organic polymers. The first applications are therefore found in the field of shipbuilding, resins, protection of wooden structures, adhesives resistant to high temperatures, refractory [2]. Geopolymers are currently of considerable interest because of their good thermal [3], chemical [4] and mechanical properties [2] and their potential for use as a green cementitious binder. The geopolymer are based on the amorphous nature of these materials and the coordination numbers of silicon and aluminum. The aim of this work is the comparison between two geopolymers: K-geopolymer and (Na, K)–geopolymer based on calcined clay at 750°C from Tamazert (north eastern Algerian) actived with alkaline potassium silicate solution and mixed sodium and pota...

Research paper thumbnail of Synthesis of geopolymers based on dredged sediment in calcined and uncalcined states

Materials Letters, 2019

The aim of this work is the synthesis of geopolymers from dredged sediments in calcined and uncal... more The aim of this work is the synthesis of geopolymers from dredged sediments in calcined and uncalcined states. Different amounts of dredged sediments (0, 5, 10, 15 and 20 wt %) were introduced within geopolymers paste. Investigations show that dredging sediments were mainly composed by calcite, muscovite and kaolinite. It was demonstrated that highest compressive strength of 22 M pa and durability in hydrochloric acid solution of the geopolymers were obtained when 15 wt% of calcined dredging sediment were added, this is due to more stable geopolymer matrix. In the other hand, calcination activates dredged sediment by changing its crystallinity into an amorphous structure of higher reactivity in alkaline solution.

Research paper thumbnail of Effect of acid attack on microstructure and composition of metakaolin-based geopolymers: The role of alkaline activator

Journal of Non-Crystalline Solids, 2017

The mineral composition of raw materials and the type of alkali cation plays an important role in... more The mineral composition of raw materials and the type of alkali cation plays an important role in the acidic resistance of geopolymers. This paper focuses on the study of chemical durability in hydrochloric acid of potassium and sodium based geopolymers. The study was carried out on two Algerian kaolins and compared with a kaolin from Charente (France). The acid degradation was studied using X-ray Diffraction, Fourier-Transform Infrared and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy. The samples based on Algerian kaolins seems to have the lowest loss in mass for formulations based on potassium due to the presence of secondary minerals (quartz and muscovite). They could have occupied the pores avoiding the release of alkali cations into the acidic solution. Regarding to sodium geopolymers, the best behavior was observed with the kaolin from Charente, which can be attributed to a more stable aluminosilicate cross-linked polymer structure formed for this material, which was corroborated with the Fourier-Transform Infrared analysis.

Research paper thumbnail of Mechanical and Dielectric Properties of High Temperature Coating Insulators Based on By-Product of Algerian Kaolin

Transactions of the Indian Ceramic Society, 2014

ABSTRACT The main objective of this work is to study the mechanical and dielectric properties of ... more ABSTRACT The main objective of this work is to study the mechanical and dielectric properties of high temperature coating insulators based on the by-product resulted from the raw kaolin treatment; this by-product represents about 21 wt% of the kaolin as commercial products. During sintering, the mineralogical phases are mainly mullite, quartz and vitreous silica besides rutile phase which is identified only at 1200° and 1500°C. The sample porosity decreases from 21% to 16%. Mechanical properties carried out by Young's modulus values are enhanced during calcinations from 54 to 57 GPa. Dielectric properties, in the frequency range of 105-109 Hz, of the samples fired at 1400° and 1500°C show that they can be considered as insulators since they exhibit a high relative permittivity (εexp) varying from 6.95 to 7.89 respectively. These parameters depend on glassy, quartz and mullite phases besides porous structures. Porosity affects considerably both the corrected relative permittivity (εc) considering the large difference between εexp, εc and the dielectric loss of the samples.

Research paper thumbnail of Stabilization of flotation wastes resulting from the treatment of Pb/Zn ore based on geopolymers

Materials Letters, 2018

The objective of this study is the stabilization of two heavy metals Pb and Zn wastes resulting f... more The objective of this study is the stabilization of two heavy metals Pb and Zn wastes resulting from the treatment by flotation of Pb/Zn ore. The Pb/Zn wastes are encapsulated in Na-geopolymer based on Algerian metakaolin. However, various amount (0, 5, 10 and 15 wt %) of wastes are introduced within geopolymers paste. Leaching test show that Lead is untraceable in all levels of waste content up to 15 wt% because lead content of the waste is very low and its presence in the leachate is below the level of detection by Atomic Absorption Spectroscopy. In the other hand, traces of Zinc were detected in the various leaching solutions. The geopolymers 28 days ages and 10 wt% give the better results due to more stable geopolymer matrix. Leaching is increased when 15wt% of waste was added due to limited capacity of geopolymers for the heavy metals and deterioration of the structure.