hydrophilic character
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Author(s):  
Mariann Chaussy ◽  
Morgan Chabannes ◽  
Arnaud Day ◽  
David Bulteel ◽  
Frederic Becquart ◽  
...  

Human activities require a growing need for raw materials. In order to contribute to sustainable development, many business sectors are focusing on biomass valorization. Whether from dedicated crops or first industrial processing, it generates materials with high potential that can be used in many fields. Non-food uses mainly concern the energy, chemical, and construction sectors. Whatever the intended application, a pre-treatment stage is essential to clean the material and/or to access a specific fraction. An additional modification may occur in order to endow the material with a new function thanks to a process known as functionalization. Uses of plant fractions (aggregates) in combination with cement offer advantages like low-density materials with attractive thermophysical properties for building. However, their development is limited by the compatibility of crop by-products with hydraulic binders such as Ordinary Portland Cement (OPC). This includes delays in setting time and hydrophilic character of vegetal components and their interaction with an alkaline environment. The aggregate/cement interfaces can therefore be strongly affected. In addition, the diversity of crop by-products and mineral binders increases the level of complexity. In order to overcome these drawbacks, the treatment of plant fractions before their use with mineral binders may result in significant benefits. In this way, various treatments have been tested, but the methods used at an industrial scale remain relatively under-researched. The purpose of this review is therefore to highlight the mechanisms involved in each specific process, thus justifying the operating conditions specific to each. This bibliography study aims to highlight potential treatments that could apply to biomass before their mixing with cementitious binders. According to the objective, a distinction can be made between extraction processes as hydrothermal or solvent treatments, assisted or not, and structural modification processes as surface treatments, impregnation, or grafting.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7110
Author(s):  
Younes Zouaoui ◽  
Ferhat Benmahiddine ◽  
Ammar Yahia ◽  
Rafik Belarbi

This paper presents an experimental investigation of the hygrothermal and mechanical properties of innovative mortar mixtures reinforced with natural fibers. Fibers extracted from palm stems (PS) and hemp (HF) were evaluated at different percentages. Scanning electron microscope (SEM) observations showed that the PS fibers have rough surfaces and very complex microstructures. Prior to their incorporation into the mortar, the fibers were subjected to different treatments to reduce their hydrophilic character. The employed treatments showed good efficiency in reducing the water absorption of both PS and HF fiber types. Furthermore, the mortar mixtures incorporating these fibers exhibited low thermal conductivity and excellent moisture buffering capacity. Indeed, the moisture buffer value (MBV) of the investigated mixtures ranged between 2.7 [g/(%HR·m2)] and 3.1 [g/(%HR·m2)], hence providing them excellent moisture regulator character. As expected, the fiber mortar mixtures showed very high porosity and low compressive strength ranging between 0.6 and 0.9 MPa after 28 days of age. The low-environmental footprint materials developed in this study are intended for thermal insulation and building filling.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5609
Author(s):  
Raluca Maria Aileni ◽  
Laura Chiriac ◽  
Doina Toma ◽  
Irina Sandulache

This paper presents a study concerning the preliminary treatments in radiofrequency (RF)oxygen (O2) plasma used to obtain a hydrophilic effect on raw cotton fabrics followed by electroconductive thin film deposition to obtain electroconductive textile surfaces. In addition, this study presents a multivariate correlation analysis of experimental parameters. The treatment using RF plasma O2 aimed to increase the hydrophilic character of the raw fabric and adherence of paste-based polymeric on polyvinyl alcohol (PVA) matrix and nickel (Ni), silver (Ag) or copper (Cu) microparticles. The purpose of the research was to develop electroconductive textiles for flexible electrodes, smart materials using a clean technology such as radiofrequency (RF) plasma O2 to obtain a hydrophilic surface with zero wastewater and reduced chemicals and carbon footprint. To achieve the foreseen results, we used advanced functionalization technologies such as RF plasma O2, followed by scraping a thin film of conductive paste-based Ni, Ag or Cu microparticles, and multivariate correlation methods to observe the dependence between parameters involved (dependent and independent variables). Overall, the fabrics treated in plasma with O2 using a kHz or MHz generator and power 100–200 W present an excellent hydrophilic character obtained in 3 min. After RF O2 plasma functionalization, a thin film based on polymeric matrix PVA and Ni microparticles have been deposited on the fabric surface to obtain electroconductive materials.


Author(s):  
JEYAKODI MOSES ◽  
Sathish P. ◽  
Keerthivasan M. ◽  
Pragadeesh R.J. ◽  
Pranesh A.

Polyethylene terephthalate is one of the important synthetic ester polymeric material used in widespread areas.  In textile industry, this fibrous material finds use in most of the garment and apparel applications due to its ease of handling, maintenance, and drying and competes with cotton materials.  However, due to the maximum hydrophobic behavior, this textile material gives number of issues like accumulation of statics, negligible moisture content, poor comfort and aesthetic characters.  Hence, in order to use this polyester material in the general textile industries particularly for garment and apparel productions, it is necessary to increase to some extent of its hydrophilic character by the application of some suitable chemicals like polyvinyl alcohol.  In these context, in this work an attempt is made to treat the polyethylene terephthalate fabric with sodium hydroxide followed by polyvinyl alcohol so as to increase the aesthetic properties.  The output received after the polyvinyl alcohol treatment on this fabric gives the good results expected for the garment applications.  


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4755
Author(s):  
Alessandro Iannaci ◽  
Adam Myles ◽  
Timothé Philippon ◽  
Frédéric Barrière ◽  
Eoin M. Scanlan ◽  
...  

Surface modification of electrodes with glycans was investigated as a strategy for modulating the development of electrocatalytic biofilms for microbial fuel cell applications. Covalent attachment of phenyl-mannoside and phenyl-lactoside adlayers on graphite rod electrodes was achieved via electrochemically assisted grafting of aryldiazonium cations from solution. To test the effects of the specific bio-functionalities, modified and unmodified graphite rods were used as anodes in two-chamber microbial fuel cell devices. Devices were set up with wastewater as inoculum and acetate as nutrient and their performance, in terms of output potential (open circuit and 1 kΩ load) and peak power output, was monitored over two months. The presence of glycans was found to lead to significant differences in startup times and peak power outputs. Lactosides were found to inhibit the development of biofilms when compared to bare graphite. Mannosides were found, instead, to promote exoelectrogenic biofilm adhesion and anode colonization, a finding that is supported by quartz crystal microbalance experiments in inoculum media. These differences were observed despite both adlayers possessing thickness in the nm range and similar hydrophilic character. This suggests that specific glycan-mediated bioaffinity interactions can be leveraged to direct the development of biotic electrocatalysts in bioelectrochemical systems and microbial fuel cell devices.


2021 ◽  
Vol 893 ◽  
pp. 45-55
Author(s):  
Ana S. Ribeiro ◽  
Sofia M. Costa ◽  
Diana P. Ferreira ◽  
Houcine Abidi ◽  
Raul Fangueiro

In this work, natural-based and biodegradable nanofibers were produced by electrospinning for drug delivery and wound dressing applications, using gelatin (Gel), chitosan (CS), cellulose nanocrystals (CNC) and natural propolis extract. The polymeric formulations and electrospinning parameters were optimized, resulting in the development of Gel/CS nanofibers with mean diameters of 97 nm. CNC were successfully introduced into the optimized Gel/CS solution and the viscosity and conductivity values were recorded. The developed nanofibers were characterized using FESEM, ATR-FTIR, TGA and WCA. The incorporation of different CNC concentrations improved the solutions’ electrospinnability and the membranes’ physical integrity. Defect-free and uniform Gel/CS/CNC nanofibers were observed by FESEM images, and the fibers’ diameters slight increased. The hydrophilic character was maintained after the CNC incorporation. Finally, Gel/CS/CNC/Propolis nanofibers demonstrated antibacterial activity against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria.


2021 ◽  
Vol 11 (10) ◽  
pp. 4354
Author(s):  
Ibtissem Ounifi ◽  
Youssef Guesmi ◽  
Claudia Ursino ◽  
Sergio Santoro ◽  
Selim Mahfoudhi ◽  
...  

Fouling has been widely recognized as the Achilles’ heel of membrane processes and the growing perception about the relevance of this critical issue has driven the development of advanced antifouling strategies. Herein, novel fouling-resistant ultrafiltration (UF) membranes for Cadmium (Cd) remediation were developed via a blending method by combining the flexibility of cellulose acetate (CA) with the complex properties of poly(acrylic acid) (PAA). A systematic characterization, based on differential scanning calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), confirmed the homogeneity of the blend favored by hydrogen interconnections between CA and PAA polymeric chains. The concentration of PAA with respect to CA played a key role in tuning the morphology and the hydrophilic character of the novel UF membranes prepared via non-solvent-induced phase separation (NIPS). UF experiments revealed the tremendous advantages of the blend since CA/PAA membranes showed superior performance with respect to the neat CA membrane in terms of (i) water permeability; (ii) Cd rejection; and (iii) antifouling resistance to humic acid (HA). Concisely, the increasing of the concentration of PAA in the casting solution was found to be beneficial to improve the flux recovery ratio (FRR) coupled with the decline of the total fouling ratio (Rt). Overall, PAA is an effective additive to prepare CA membranes with enhanced antifouling properties exploitable for the remediation of water bodies contaminated by heavy metals via UF process.


Author(s):  
Francesco Tumino ◽  
Carlo Grazianetti ◽  
Christian Martella ◽  
Marina Ruggeri ◽  
Valeria Russo ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
pp. 833-846

The intense consumption of conventional plastics has been generating a series of problems for nature due to the accumulation of municipal solid waste because of its difficult degradation. Therefore, the use of biodegradable polymers becomes a good option to minimize these effects. Poly (lactide acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) is a biodegradable blend that can be used mainly in applications that have a short shelf life. So, it is important to know the total biodegradation time of this blend. For this reason, PLA/PBAT films (1.5 x 1.5 x 0.15 cm) were produced by thermal compression molding to be subjected to biodegradation tests in soil and aqueous medium for 180 days. The films were characterized by visual analysis, weight loss measurements, differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), contact angle, and scanning electron microscopy (SEM). DSC showed an increase of 0.7% in PLA crystallinity subjected to the aqueous medium, while FT-IR showed a reduction in the bands at 1710 cm-1 and 1100 cm-1, as a result of hydrolysis for both methodologies. The blend's hydrophilic character was increased after both degradation processes, presenting a reduction of 34.5% in the contact angle after biodegradation in soil. From the results, it was possible to conclude that PLA/PBAT films did not degrade completely, as expected, but showed signs that indicated the beginning of the degradation. The degradation was more effective in the aqueous medium.


2021 ◽  
pp. 039139882199411
Author(s):  
Shafiq Uz Zaman ◽  
Muhammad Khaliq U Zaman ◽  
Muhammad Irfan ◽  
Rafiq Sikander ◽  
Masooma Irfan ◽  
...  

In the current study, dahllite/hydroxyapatite/collagen filler extracted via calcination of wasted chicken bone was blended with PSf polymer to obtain highly biocompatible, and antifoulant hemodialysis membranes. FTIR and Raman spectroscopic analysis was done to obtain information about the bonding chemistry of the obtained filler. The intermolecular interaction that existed between dahllite/hydroxyapatite/collagen filler and pristine PSf was confirmed by Raman spectroscopic study. The PSf polymer exhibited a sponge-like structure owing to its high thickness and slow exchange with non-solvent in coagulation bath whilst the instantaneous de-mixing course produced finger-like capillaries in dahllite/hydroxyapatite/collagen filler based PSf membranes as exposed by SEM photographs. The presence of different wt. % of filler composition in the PSf matrix improved the mechanical strength as revealed by fatigue analysis. The hydrophilic character improved by 78% while leaching consistency adjusted to 0%–4%. Pure water permeation (PWP) flux improved by nine times. The pore profile improved with the addition of filler as revealed by hydrophilicity experiment, PWP flux, and SEM micrographs. Fouling evaluation results disclosed that filler based membranes showed 36% less adsorption of protein (BSA) solution together with more than 84% flux recovery ratio. The biocompatibility valuation analysis unveiled that membranes composed of filler showed extended prothrombin and thrombin coagulation times, reduced activation of fibrinogen mass, and less adhesion of plasma proteins in comparison with pristine PSf membrane. The adsorption capacity of fabricated membranes for urea and creatinine improved by 31% (in the case of urea) and 34% (in the case of creatinine) in contrast with pristine PSf membrane. The overall results showed that the M-3 membrane was optimized in terms of surface properties, protein adhesion, anticoagulation activity, and adsorption amount of urea and creatinine.


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