To address escalating environmental and sustainability concerns of petroleum-based superplasticiz... more To address escalating environmental and sustainability concerns of petroleum-based superplasticizers (SPs), this work aims to develop sustainable and eco-friendly starch-based SPs using gamma radiation for maintaining the desired workability of geopolymeric pastes. Specifically, two green SPs were prepared from starch via radiationinduced grafting of two sulfonic group-bearing monomers, namely 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and 4-styrene sulfonic acid sodium salt (Na4SS). The grafting reaction was improved by initial modification of starch with glycidyl methacrylate to insert vinyl groups into the starch backbone. The modified starch samples were characterized by a variety of analytical techniques such as FTIR, 1 H NMR, EDX, SLS, and viscometry. The prepared SPs exhibited high stability in aqueous 5 % NaOH. The effect of the prepared SPs on the fresh properties of GGBFS/MK geopolymer was studied using the mini slump test, zeta potential, adsorption capacity, and setting time. They significantly improved the paste flowability and dispersion compared to the control. Notably, the aromatic Na4SS-grafted starch displayed a comparable enhancement to the commercial PNS, while outperforming the aliphatic AMPS-grafted sample. This emphasizes the potential of these green SPs to address the challenges posed by the petroleum-based SPs and maximize the benefit of using starch as a green renewable resource.
According to the sustainability concept, this work developed a green geopolymeric composite (Geo)... more According to the sustainability concept, this work developed a green geopolymeric composite (Geo) prepared by mingling 50 wt%slag+ 50 wt%brick-waste (BW) as an alternative eco-friendly and low-cost cementitious material. The main target of this study is to fnd a solution to the problem of poor characteristics of binding materials containing high proportions of BW; most previous studies recommended using only 10-20 wt%BW. The compressive-strength results showed that replacing slag with 50 wt% BW reduced the strength from 47 to 24.6 MPa at normal curing conditions for 28-days, referring to the detrimental impact of BW on mechanical performance. In an endeavour to enhance the mechanical performance of this composite, different doses from laboratory-prepared tungsten oxide nanoparticles (0.25, 0.5, 1 wt%WO 3-NPs) and hydrothermal curing at various steam-pressure/periods were used. From an economic point of view, hydrothermally treated Geo-paste modified with 0.25 wt%WO 3-NPs at 3 bar/4hrs was selected as an ideal composition/curing-conditions; the compressive-strength reached 54.5 MPa exceeding the standard limit of Portland cement (42.5 MPa). This clearly shows the synergistic role of using WO 3-NPs and hydrothermal curing to enhance the compressive-strength, which was confirmed using different analysis techniques. XRD, TGA/DTG and SEM/mapping proved that the catalytic performance of WO 3-NPs/hydrothermal-curing participates in augmenting binding hydrates, creating a cubic-stable-phase of tricalcium-aluminate-hydrate (C 3 AH 6) and different types of zeolitic-like structure (spherical Zeolite-NaP, rods analcime and stacked-plates cancrinite). To maximize the benefits of employing WO 3-NPs in the developed composites, their anti-microbial activity was studied. The measured inhibition zone around specimens containing WO 3-NPs proved that these composites have a superior self-cleaning efficiency against Candida albicans, Mucor circinelloides, Salmonella typhi and Staphylococcus aureus due to the WO 3-NPs' photocatalytic activity.
Naphthalene‐based chalcone derivative was successfully synthesized through the condensation of 2,... more Naphthalene‐based chalcone derivative was successfully synthesized through the condensation of 2,4‐dichlorobenzaldehyde with 2‐acetylnaphthalene. This chalcone, denoted as compound 1, demonstrated a versatile reactivity upon treatment with both nitrogen and carbon nucleophiles, and yielded diverse heterocyclic scaffolds such as pyrazoline, thiazole, pyrimidine, pyran, and pyridine derivatives. The pyrazoline aldehyde derivative 7 was further derivatized to produce the hydrazide‐hydrazone 13, namely, (1H‐pyrazol‐1‐yl)methylene)acetohydrazide, which was exploited to synthesize derivatives of 2‐oxo‐2H‐chromene‐3‐carbohydrazide 14, 2‐(4‐oxo‐4,5‐dihydrothiazol‐2‐yl)acetohydrazide 15, and 3‐(4‐nitrophenyl)acrylohydrazide 16. All the newly synthesized compounds were characterized by melting point, elemental analysis, as well as FT‐IR, 1H‐NMR and mass spectroscopy. Furthermore, these heterocyclic derivatives were screened for their antioxidant capacities using the DPPH radical assay. The re...
Journal of biomedical materials research. Part A, Jan 13, 2017
Poly(lactic acid) (PLA) has shown much success in the preparation of tissue engineering scaffolds... more Poly(lactic acid) (PLA) has shown much success in the preparation of tissue engineering scaffolds as it can be fabricated with a tailored architecture. However, the PLA surface has drawbacks including the lack of biofunctional motifs which are essential for high affinity to biological cells. Therefore, this study describes a multistep physicochemical approach for the immobilization of D-glucosamine (GlcN), a naturally occurring monosaccharide having many biological functions, on the PLA surface aiming at enhancing the cell proliferation activity. In this approach, poly(acrylic acid) (PAAc) spacer arms are firstly introduced into the PLA surface via plasma post-irradiation grafting technique. Then, covalent coupling or physical adsorption of GlcN with/on the PAAc spacer is carried out. Factors affecting the grafting yield are controlled to produce a suitable spacer for bioimmobilization. X-ray photon spectroscopic (XPS) analyses confirm the immobilization of GlcN on the PLA surface. ...
Colloids and surfaces. B, Biointerfaces, Jan 28, 2016
The aim of this study was to develop the potential tissue engineering applications of d-glucosami... more The aim of this study was to develop the potential tissue engineering applications of d-glucosamine (GlcN) immobilized onto the surface of a biodegradable matrix in order to induce a desired biological effect at biointerfaces. Thus, for sample preparation we used a novel multistep physicochemical approach. In the first step the poly(lactic acid) (PLA) films were exposed to a low pressure plasma in air atmosphere, followed by radical graft copolymerization with acrylic acid to yield a carboxyl-functionalized spacer layer on the PLA surface. The carboxyl groups were then coupled to GlcN molecules via the carbodiimide chemistry. The developed surfaces were characterized by X-ray Photoelectron Spectroscopy (XPS), Contact angle measurements and Atomic Force Microscopy (AFM). A preliminary study on the proliferation of fibroblasts on the developed surfaces was performed using the NIH/3T3 cell line.
To address escalating environmental and sustainability concerns of petroleum-based superplasticiz... more To address escalating environmental and sustainability concerns of petroleum-based superplasticizers (SPs), this work aims to develop sustainable and eco-friendly starch-based SPs using gamma radiation for maintaining the desired workability of geopolymeric pastes. Specifically, two green SPs were prepared from starch via radiationinduced grafting of two sulfonic group-bearing monomers, namely 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and 4-styrene sulfonic acid sodium salt (Na4SS). The grafting reaction was improved by initial modification of starch with glycidyl methacrylate to insert vinyl groups into the starch backbone. The modified starch samples were characterized by a variety of analytical techniques such as FTIR, 1 H NMR, EDX, SLS, and viscometry. The prepared SPs exhibited high stability in aqueous 5 % NaOH. The effect of the prepared SPs on the fresh properties of GGBFS/MK geopolymer was studied using the mini slump test, zeta potential, adsorption capacity, and setting time. They significantly improved the paste flowability and dispersion compared to the control. Notably, the aromatic Na4SS-grafted starch displayed a comparable enhancement to the commercial PNS, while outperforming the aliphatic AMPS-grafted sample. This emphasizes the potential of these green SPs to address the challenges posed by the petroleum-based SPs and maximize the benefit of using starch as a green renewable resource.
According to the sustainability concept, this work developed a green geopolymeric composite (Geo)... more According to the sustainability concept, this work developed a green geopolymeric composite (Geo) prepared by mingling 50 wt%slag+ 50 wt%brick-waste (BW) as an alternative eco-friendly and low-cost cementitious material. The main target of this study is to fnd a solution to the problem of poor characteristics of binding materials containing high proportions of BW; most previous studies recommended using only 10-20 wt%BW. The compressive-strength results showed that replacing slag with 50 wt% BW reduced the strength from 47 to 24.6 MPa at normal curing conditions for 28-days, referring to the detrimental impact of BW on mechanical performance. In an endeavour to enhance the mechanical performance of this composite, different doses from laboratory-prepared tungsten oxide nanoparticles (0.25, 0.5, 1 wt%WO 3-NPs) and hydrothermal curing at various steam-pressure/periods were used. From an economic point of view, hydrothermally treated Geo-paste modified with 0.25 wt%WO 3-NPs at 3 bar/4hrs was selected as an ideal composition/curing-conditions; the compressive-strength reached 54.5 MPa exceeding the standard limit of Portland cement (42.5 MPa). This clearly shows the synergistic role of using WO 3-NPs and hydrothermal curing to enhance the compressive-strength, which was confirmed using different analysis techniques. XRD, TGA/DTG and SEM/mapping proved that the catalytic performance of WO 3-NPs/hydrothermal-curing participates in augmenting binding hydrates, creating a cubic-stable-phase of tricalcium-aluminate-hydrate (C 3 AH 6) and different types of zeolitic-like structure (spherical Zeolite-NaP, rods analcime and stacked-plates cancrinite). To maximize the benefits of employing WO 3-NPs in the developed composites, their anti-microbial activity was studied. The measured inhibition zone around specimens containing WO 3-NPs proved that these composites have a superior self-cleaning efficiency against Candida albicans, Mucor circinelloides, Salmonella typhi and Staphylococcus aureus due to the WO 3-NPs' photocatalytic activity.
Naphthalene‐based chalcone derivative was successfully synthesized through the condensation of 2,... more Naphthalene‐based chalcone derivative was successfully synthesized through the condensation of 2,4‐dichlorobenzaldehyde with 2‐acetylnaphthalene. This chalcone, denoted as compound 1, demonstrated a versatile reactivity upon treatment with both nitrogen and carbon nucleophiles, and yielded diverse heterocyclic scaffolds such as pyrazoline, thiazole, pyrimidine, pyran, and pyridine derivatives. The pyrazoline aldehyde derivative 7 was further derivatized to produce the hydrazide‐hydrazone 13, namely, (1H‐pyrazol‐1‐yl)methylene)acetohydrazide, which was exploited to synthesize derivatives of 2‐oxo‐2H‐chromene‐3‐carbohydrazide 14, 2‐(4‐oxo‐4,5‐dihydrothiazol‐2‐yl)acetohydrazide 15, and 3‐(4‐nitrophenyl)acrylohydrazide 16. All the newly synthesized compounds were characterized by melting point, elemental analysis, as well as FT‐IR, 1H‐NMR and mass spectroscopy. Furthermore, these heterocyclic derivatives were screened for their antioxidant capacities using the DPPH radical assay. The re...
Journal of biomedical materials research. Part A, Jan 13, 2017
Poly(lactic acid) (PLA) has shown much success in the preparation of tissue engineering scaffolds... more Poly(lactic acid) (PLA) has shown much success in the preparation of tissue engineering scaffolds as it can be fabricated with a tailored architecture. However, the PLA surface has drawbacks including the lack of biofunctional motifs which are essential for high affinity to biological cells. Therefore, this study describes a multistep physicochemical approach for the immobilization of D-glucosamine (GlcN), a naturally occurring monosaccharide having many biological functions, on the PLA surface aiming at enhancing the cell proliferation activity. In this approach, poly(acrylic acid) (PAAc) spacer arms are firstly introduced into the PLA surface via plasma post-irradiation grafting technique. Then, covalent coupling or physical adsorption of GlcN with/on the PAAc spacer is carried out. Factors affecting the grafting yield are controlled to produce a suitable spacer for bioimmobilization. X-ray photon spectroscopic (XPS) analyses confirm the immobilization of GlcN on the PLA surface. ...
Colloids and surfaces. B, Biointerfaces, Jan 28, 2016
The aim of this study was to develop the potential tissue engineering applications of d-glucosami... more The aim of this study was to develop the potential tissue engineering applications of d-glucosamine (GlcN) immobilized onto the surface of a biodegradable matrix in order to induce a desired biological effect at biointerfaces. Thus, for sample preparation we used a novel multistep physicochemical approach. In the first step the poly(lactic acid) (PLA) films were exposed to a low pressure plasma in air atmosphere, followed by radical graft copolymerization with acrylic acid to yield a carboxyl-functionalized spacer layer on the PLA surface. The carboxyl groups were then coupled to GlcN molecules via the carbodiimide chemistry. The developed surfaces were characterized by X-ray Photoelectron Spectroscopy (XPS), Contact angle measurements and Atomic Force Microscopy (AFM). A preliminary study on the proliferation of fibroblasts on the developed surfaces was performed using the NIH/3T3 cell line.
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