Papers by Hatem Abushammala
One-Step to Prepare Lignin Based Fluorescent Nanoparticles with Excellent Radical Scavenging Activity
Journal of renewable materials, 2024
Journal of Applied Polymer Science, Jun 17, 2013
Poly(L-lactic acid-co-succinic acid-co-1,4-butane diol) (PLASB) was synthesized by direct condens... more Poly(L-lactic acid-co-succinic acid-co-1,4-butane diol) (PLASB) was synthesized by direct condensation copolymerization of L-lactic acid (LA), succinic acid (SA), and 1,4-butanediol (BD) in the bulk using titanium(IV) butoxide as a catalyst. The weight-average molecular weight of PLASB was 2.1Ý 10 5 when the contents of SA and BD were each 0.5 mol/100 mol of LA. Electrospinning was used to fabricate porous membranes from this newly synthesized bioabsorbable PLASB dissolved in mixed solvents of methylene chloride and dimethylformamide. Scanning electron microscopy (SEM) images indicated that the fiber diameters and nanostructured morphologies of the electrospun membranes depended on the processing parameters, such as the solvent ratio and the polymer concentration. By adjusting both the solvent mixture ratio and the polymer concentration, we could fabricate uniform nanofiber non-woven membranes. Cell proliferation on the electrospun porous PLASB membranes was evaluated using mouse fibroblast cells; we compare these results with those of the cell responses on bulk PLASB films.
Cellulose, May 10, 2017
Cellulose acetylation has been reported as a side reaction of cellulose treatment with the ionic ... more Cellulose acetylation has been reported as a side reaction of cellulose treatment with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) (Karatzos et al. in Cellulose 19:307-312, 2012) and other 1,3-dialkylimidazolium acetate ionic liquids. 1-Acetylimidazole (AcIm), an [EMIm][OAc] impurity, has been found to be the actual acetylating agent (Zweckmair et al. in Cellulose 22:3583-3596, 2015), and the degree of acetylation was relatively low, below a DS of approx. 0.1%. Higher degrees of cellulose acetylation (DS [ 10%) have been observed when the entire wood was mixed with [EMIm][OAc] instead of cellulosic pulp only (Abushammala et al. in Carbohydr Polym 134:609-616, 2015). In this paper, we explore the impact of wood constituents, mainly lignin, on cellulose acetylation using AcIm. The results demonstrate that lignin itself can be readily acetylated upon mixing with AcIm, and-noteworthy-that lignin presence significantly accelerates cellulose acetylation. The initial rate of cellulose acetylation by AcIm increased from 1.8 to 4.7%/h when only 1% of lignin, based on cellulose mass, was added. A mechanistic study employing cellulose and lignin model compounds showed lignin to be more susceptible to acetylation than cellulose and to act as an intermediate acetyl group source for further cellulose acetylation in a catalytic scenario.
Sustainability
The pulp and paper industry (PPI) is a major contributor to the global economy, but it also poses... more The pulp and paper industry (PPI) is a major contributor to the global economy, but it also poses a challenge for waste disposal, as it generates large amounts of several waste streams. Among these, paper rejects are generated during the papermaking process and could account for up to 25% of the produced paper. Moreover, hundreds of millions of tons of paper are produced annually that end up in landfills if not burnt or recycled. Furthermore, the PPI significantly contributes to climate change and global warming in the form of deforestation and water and air pollution. Therefore, the impact of this industry on the sustainability of natural resources and its adverse environmental health effects requires special attention. This review focuses on discussing the sustainable routes to utilize paper waste and rejects from the PPI towards a circular economy. At first, it discusses the industry itself and its environmental impact, followed by the possible sustainable approaches that can be ...
Nanomaterials
Electronic waste (e-waste) is the fastest growing waste stream and its negative impact on the env... more Electronic waste (e-waste) is the fastest growing waste stream and its negative impact on the environment and human health is major because of the toxicity and non-biodegradability of its constituents. For their biodegradability and nontoxicity, bio-based materials have been proposed as potential material candidates in the field of electronics. Among these, cellulose nanocrystals (CNCs) have many interesting properties including biodegradability, high mechanical strength, and possibility to functionalize. In terms of electrical properties, CNCs are electrically insulated, limiting their potential in electronics. This work aims to build up a poly(o-toluidine)-like shell around the CNCs to render them conductive. For this goal, the surface of the CNCs was carbamated using 2,4-toluene diisocyanate through the para-isocyanates and the ortho-isocyanates were later hydrolyzed to amine groups using HCl-acidified dimethylsulfoxide. The resultant o-toluidine-like molecules on the CNC surface...
Sustainability
Electronic waste (e-waste) is the fastest-growing class of waste because of the remarkable demand... more Electronic waste (e-waste) is the fastest-growing class of waste because of the remarkable demand for various electronic gadgets such as mobiles and laptops. Moreover, its improper disposal is life-threatening because it includes hundreds of different substances, many of which are toxic elements and pollutants that can leach to soil and surface and groundwater or be emitted into the air, causing a major negative impact on the environment and public health. As a result, studies on the sustainable management of e-waste have gained increasing attention from researchers globally in the last decade to explore practical strategies to reduce or utilize this special waste. This review aims to provide an in-depth understanding of the major aspects of e-waste, including its definition, composition, and the impact of its end-of-life disposal on human health and the environment, while also focusing on some practical sustainable solutions and strategies toward effective e-waste management. It wi...
Sustainability
Sustainability in the United Arab Emirates (UAE) is a critical issue due to the steady rises in p... more Sustainability in the United Arab Emirates (UAE) is a critical issue due to the steady rises in population and regional economic growth. Therefore, an urgent need arises each passing time on ensuring efficient resource utilization and waste management in all sectors; industrial, agricultural, and residential. In the residential sector, residents’ greenness with a focus on their waste-management knowledge and practices could be impacted by their socio-demographics such as age, gender, educational level, and income. Several studies investigated this impact but reported varying outcomes about its degree. Therefore, this work aims to investigate the knowledge, attitudes, and practices (KAPs) of UAE residents towards waste management in their households and how impacted their KAPs are by their demographics. For this goal, a questionnaire was distributed among 400 UAE residents of different genders, ages, and educational levels, and the collected responses were qualitatively and quantitat...
Novel Ionic Liquid-Mediated Technologies for the Extraction of Nanocellulose Directly from Wood
The current environmental concerns generate an increasing interest for the extraction and process... more The current environmental concerns generate an increasing interest for the extraction and processing of bio-based polymers and materials. Among these is Nanocellulose. Cellulose Nanocrystals (CNCs), one form of nanocellulose, is a high-value nanomaterial with very interesting properties: light weight (density = 1.6 g/cm) with an elastic modulus higher than that for Kevlar fibers (110-220 GPa for CNCs, 125-130 GPa for Kevlar) (Moon, Martini et al. 2011). It also lends itself for a wide range of functional modifications and organizational patterns. Therefore, CNCs has been explored for many applications from automotive industry, membranes, to tissue engineering and pharmaceutical formulation. The production methods of CNCs have varied a lot with the sulfuric acid hydrolysis developed by Ranby in 1949 being the most famous till now. However, all these methods share one main disadvantage; they all require pure forms of cellulose, such as pulp and microcrystalline cellulose, as a startin...
Matière de gel cellulosique en tant qu'excipient pharmaceutique
L'invention concerne un procede de fabrication d'un comprime pharmaceutique, lequel proce... more L'invention concerne un procede de fabrication d'un comprime pharmaceutique, lequel procede consiste a (a) combiner (i) un gel de cellulose reticule aqueux avec (ii) une charge et (iii) un agent actif pour former un melange de ceux-ci ; (b) couler le melange pour former un comprime humide ; (c) a secher le comprime humide pour former un comprime pharmaceutique sec ; puis (d) enrober de maniere facultative le comprime (par exemple, par un enrobage enterique). L'invention concerne egalement des comprimes pharmaceutiques fabriques par de tels procedes.
Polymers, 2021
Recent developments in the application of lignocellulosic materials for oil spill removal are dis... more Recent developments in the application of lignocellulosic materials for oil spill removal are discussed in this review article. The types of lignocellulosic substrate material and their different chemical and physical modification strategies and basic preparation techniques are presented. The morphological features and the related separation mechanisms of the materials are summarized. The material types were classified into 3D-materials such as hydrophobic and oleophobic sponges and aerogels, or 2D-materials such as membranes, fabrics, films, and meshes. It was found that, particularly for 3D-materials, there is a clear correlation between the material properties, mainly porosity and density, and their absorption performance. Furthermore, it was shown that nanocellulosic precursors are not exclusively suitable to achieve competitive porosity and therefore absorption performance, but also bulk cellulose materials. This finding could lead to developments in cost- and energy-efficient ...
Polymers, 2020
Despite the many interesting properties of cellulose nanocrystals (CNCs), their hydrophilicity is... more Despite the many interesting properties of cellulose nanocrystals (CNCs), their hydrophilicity is one of the main challenges for their processing with hydrophobic polymers and matrices. To overcome this challenge, this paper describes the preparation of brush-like CNCs with tailored surface properties by grafting alcohols of different chain lengths onto their surfaces. Ethanol, 1-butanol, 1-hexanol, and 1-octanol were grafted on the CNC surface using 2,4-toluene diisocyanate (TDI) as a linker. The CNCs were characterized for their structural, morphological, surface, and thermal properties. Because of the grafting, the water contact angle of the CNCs significantly increased from 32° to up to 120°, which was dependent on the chain length of the grafted alcohol. The thermal stability of the CNCs was also improved, mainly as a result of the reaction of TDI with the CNC hydroxyl groups. Later, the CNCs were used to reinforce films of poly(butylene succinate) (PBS), which were then charac...
Polymers, 2019
2,4-toluene diisocyanate (TDI) has been commonly used to bind molecules and polymers onto the sur... more 2,4-toluene diisocyanate (TDI) has been commonly used to bind molecules and polymers onto the surface of cellulose nanocrystals (CNCs). Such a process usually involves two steps: (1) the more reactive para-isocyanates (p-NCOs) of TDI are reacted with the surface hydroxyl groups of CNCs then (2) the ortho-isocyanates (o-NCOs) are reacted with certain desired molecules. During the first reaction, an ideal para/ortho selectivity could be impossible to achieve, as o-NCOs are not fully unreactive. Therefore, there is a need to better understand the reaction between CNCs and TDI towards a maximum para/ortho selectivity. For that goal, CNCs were reacted with TDI under varying temperatures (35–75 °C) and TDI/CNCs molar ratios (1–5). The amount of the reacted TDI was estimated using elemental analysis while the free o-NCO groups were quantified following the hydrolysis method of Abushammala. The results showed that temperature had a negative impact on para/ortho selectivity while TDI/CNCs mo...
Journal of Composites Science
Several studies have been conducted to improve the mechanical and other value-added properties of... more Several studies have been conducted to improve the mechanical and other value-added properties of glass fiber-reinforced epoxy (GFRE) composites by the addition of different fillers. In this work, waste iron filings (WIFs) obtained from the steel industry were incorporated into GFRE composite samples in varying amounts of up to 50% (%w) to improve their mechanical and electrical properties. The results showed that, with increasing WIF loading from 0 w% to 50 w%, the resultant composite density gradually increased from 1.4 to 2.1 g/cm3. Surface hardness, Young’s modulus, and tensile strength also increased significantly with the addition of up to 9 w% of WIF followed by a significant drop with more WIF addition due to agglomeration. Overall, Young’s modulus of the GFRE samples with any WIF content was higher than that of the GFRE composite with no WIF. The elongation at break results showed that the GFRE samples were less ductile upon WIF addition, which decreased from 2% to 0.6% upo...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021
Wood aging is a topic of great interest due to its impact on wood performance and durability as a... more Wood aging is a topic of great interest due to its impact on wood performance and durability as a construction material. Therefore, it is important to develop accurate methods to monitor aging and understand its mechanisms. Atomic force microscopy (AFM) is a powerful tool to study the changes in materials properties in the nanoscale. We aim in this paper at developing an accurate AFM-based method to understand the wood aging phenomenon by studying the surface changes of wood pits as they are the most susceptible wood structures to aging. For this objective, surface adhesion measurements were performed to detect any chemical changes on the surface of wood structures by estimating the relative adhesion force (RAF). The results showed that unfunctionalized AFM tips should not be used for monitoring aging as they fail to simply differentiate between the different wood structures (cell wall, lumen, pit torus and pit margo) as the RAF values were around 10 for the four structures. With a focus on pit structures (torus and margo), AFM tips functionalized with hydroxyl groups showed significantly different RAF values for torus and margo suggesting the ability of these tips in detecting possible chemical changes. The RAF values of torus and margo were around 216 and 530 for unaged wood, respectively. This indicates that, for the first time, the use of functionalized tips does not only improve the interaction between the tips and wood in general but also improves the sensitivity to its different structures. This also allowed monitoring wood aging as the RAF values for torus and margo dropped to 152 and 301 upon aging,
Comparative Assessment of Methods for Producing Cellulose I Nanocrystals from Cellulosic Sources
Nanocelluloses: Their Preparation, Properties, and Applications, 2017
Crystals, 2020
The hydrophilicity of cellulose nanocrystals (CNCs) is a major challenge for their processing wit... more The hydrophilicity of cellulose nanocrystals (CNCs) is a major challenge for their processing with hydrophobic polymers and matrices. As a result, many surface modifications have been proposed to hydrophobize CNCs. The authors showed in an earlier study that grafting alcohols of different chain lengths onto the surface of CNCs using toluene diisocyanate (TDI) as a linker can systematically hydrophobize CNCs to a water contact angle of up to 120° depending on the alcohol chain length. Then, the hydrophobized CNCs were used to mechanically reinforce poly(butylene succinate) (PBS), which is a hydrophobic polymer. As a result of hydrophobization, PBS/CNCs interfacial adhesion and the composite mechanical properties significantly improved with the increasing CNC contact angle. Continuing on these results, this paper investigates the impact of CNC surface properties on the crystallization behavior of PBS using differential scanning calorimetry (DSC). The results showed that the crystalliz...
Polymers, 2020
Ionic liquids have shown great potential in the last two decades as solvents, catalysts, reaction... more Ionic liquids have shown great potential in the last two decades as solvents, catalysts, reaction media, additives, lubricants, and in many applications such as electrochemical systems, hydrometallurgy, chromatography, CO2 capture, etc. As solvents, the unlimited combinations of cations and anions have given ionic liquids a remarkably wide range of solvation power covering a variety of organic and inorganic materials. Ionic liquids are also considered “green” solvents due to their negligible vapor pressure, which means no emission of volatile organic compounds. Due to these interesting properties, ionic liquids have been explored as promising solvents for the dissolution and fractionation of wood and cellulose for biofuel production, pulping, extraction of nanocellulose, and for processing all-wood and all-cellulose composites. This review describes, at first, the potential of ionic liquids and the impact of the cation/anion combination on their physiochemical properties and on thei...
Molecules, 2019
Nanocellulose has been subjected to a wide range of chemical modifications towards increasing its... more Nanocellulose has been subjected to a wide range of chemical modifications towards increasing its potential in certain fields of interest. These modifications either modulated the chemistry of the nanocellulose itself or introduced certain functional groups onto its surface, which varied from simple molecules to polymers. Among many, aliphatic and aromatic mono- and di-isocyanates are a group of chemicals that have been used for a century to modify cellulose. Despite only being used recently with nanocellulose, they have shown great potential as surface modifiers and chemical linkers to graft certain functional chemicals and polymers onto the nanocellulose surface. This review discusses the modification of cellulose and nanocellulose using isocyanates including phenyl isocyanate (PI), octadecyl isocyanate (OI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), and their derivatives and polymers. It also presents the most commonly used...
Cellulose, 2019
Pulp fibrillation results from refining and is of prime importance for papermaking. Yet a structu... more Pulp fibrillation results from refining and is of prime importance for papermaking. Yet a structural parameter reflecting the extent of fibrillation remains elusive. In this work, we demonstrate that in refined pulps, the interfibrillar distance at water saturated state (L s), as derived from the interference factor from small angle X-ray scattering, structurally reflects fibrillation degree. Interestingly, the minimal L obtained at low water content is close to the crystal thickness derived from wide angle X-ray scattering. For a series of refined pulp samples, significant regressions are established between L s and equilibrium moisture content, transmittance (T%), surface energy components (c LW , c AB), and the normalized crystallinity index (CrI n). These regressions establish L s as a unique structural parameter for quantifying the fibrillation degree and derived properties of refined pulps without the need of a multi-parameter and timeconsuming analyses.
Polymers, 2017
Imidazole is reported to be an effective reactant for the production of nanocellulose from hardwo... more Imidazole is reported to be an effective reactant for the production of nanocellulose from hardwood pulp. The morphologies and surface properties of the nanocellulose can be simply tailored according to the water content in the imidazole system: with pure imidazole, cellulose nanofibrils (CNFs) in a yield of 10 wt % can be produced. With 25 wt % of water in imidazole, cellulose nanocrystals (CNCs) are obtained in 20 wt % yield. Both nanocelluloses exhibit crystallinity indices in the order of 70%. Interestingly, they retain the original xylan from the pulp with ca. 9-10 wt % of residual xylan content.
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Papers by Hatem Abushammala