Flame retardant coatings prepared using layer by layer assembly: A review

The process of protein crosslinking comprises the chemical, enzymatic, or chemoenzymatic formation of new covalent bonds between polypeptides. This allows (1) the site-directed coupling of proteins with distinct properties and (2) the de novo assembly of polymeric protein networks. Transferases, hydrolases, and oxidoreductases can be employed as catalysts for the synthesis of crosslinked proteins, thereby complementing chemical crosslinking strategies. Here, we review enzymatic approaches that are used for protein crosslinking at the industrial level or have shown promising potential in investigations on the lab-scale. We illustrate the underlying mechanisms of crosslink formation and point out the roles of the enzymes in their natural environments. Additionally, we discuss advantages and drawbacks of the enzyme-based crosslinking strategies and their potential for different applications.

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Enzyme-catalyzed protein crosslinking

Textile waste, dyes/inorganic salts separation of cerium oxide-loaded loose nanofiltration polyethersulfone membranes

Extraordinary photocatalytic activity, non-toxicity, high availability, biocompatibility, and low price make TiO 2 nanoparticles particularly attractive for manufacturing of different high value-added products. During the past several years, many efforts have been made to immobilize TiO 2 nanoparticles onto textile materials with an aim to produce goods with multifunctional properties such as UV protective, self-cleaning and antibacterial. The processing of textile materials with TiO 2 nanoparticles is relatively simple, but insufficient binding efficiency between certain fibers and TiO 2 nanoparticles imposes a problem concerning the stability and durability of nanocomposite systems during their exploitation. Therefore, recent studies were more oriented toward chemical and physico-chemical modification of fiber surfaces that may enhance the binding efficiency of TiO 2 nanoparticles. This article looks at some latest advances in finishing of different textile materials with TiO 2 nanoparticles.

Functionalization of textile materials with TiO2 nanoparticles

A novel and efficient process is reported for fabrication of electroconductive, self-cleaning, antibacterial and antifungal cellulose textiles using a graphene/titanium dioxide nanocomposite. Cotton fabric was loaded with graphene oxide using a simple dipping coating method. The graphene oxide-coated cotton fabrics were then immersed in TiCl3 aqueous solution as both a reducing agent and a precursor to yield a fabric coated with graphene/titanium dioxide nanocomposite. The crystal phase, morphology, microstructure and other physicochemical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and UV-Vis reflectance spectroscopy. Electrical resistance, self-cleaning performance, antimicrobial activity and cytotoxicity of treated fabrics were also assessed. The electrical conductivity of the graphene/titanium dioxide nanocomposite-coated fabrics was improved significantly by the presence of graphene on the surface of cotton fabrics. The self-cleaning efficiency of the treated fabrics was tested by degradation of methylene blue in aqueous solution under UV and sunlight irradiations. The results indicated that the decomposition rates of methylene blue were improved by the addition of graphene to the TiO2 treatment on fabrics. Moreover, the graphene/titanium dioxide nanocomposite-coated cotton samples had negligible toxicity and possessed excellent antimicrobial activity.

Using graphene/TiO2 nanocomposite as a new route for preparation of electroconductive, self-cleaning, antibacterial and antifungal cotton fabric without toxicity

A novel durable flame-retardant cotton fabric using sodium hypophosphite, nano TiO2 and maleic acid

Effect of [EMIM][BF4] ionic liquid on the properties of ultrafiltration membranes

Phase separation and performance of polyethersulfone/cellulose nanocrystals membranes

Application of a colloid of nano-titanium dioxide (nano-TiO2), maleic acid (MA), sodium hypophosphite (SHP), and triethanol amine on cotton fabrics through pad–dry–cure process was investigated to produce a cross-link cotton fabric with self-cleaning properties without yellowing. The central composite design was used for variables based on Design of Expert software. The degradation of methylene blue on the surfaces of treated fabrics was monitored to investigate the self-cleaning property. Also the crease recovery angles (CRA) of the fabrics was studied to investigate cross-linking of cotton fabric. Moreover, the surfaces of the treated cotton fabrics were observed by scanning electron microscopy (SEM). The optimum treatment conditions to obtain cross-linking and self-cleaning properties on the cotton fabric were introduced. Increasing concentrations of MA to 20% increased the fabric CRA due to cross-linking of cellulose in the presence of MA and SHP. The treated fabrics have good self-cleaning performanc...

Nano-TiO2/maleic acid/triethanol amine/sodium hypophosphite colloid on cotton to produce cross-linking and self-cleaning properties

Mixed matrix concept using cellulose nanosheets (CNs) and polyethersulfone was employed to fabricate hierarchical porous membrane with potential application for efficient dye/salt mixture fractionation. To this end, CNs was extracted by acid hydrolysis of alpha cellulose and incorporated in polyethersulfone casting solutions at four concentration levels. After that, membranes were manufactured by typical nonsolvent induced phase separation method. Effect of CNs incorporation on thermodynamic stability and phase separation behavior of polymer solution was investigated by construction of phase diagram. In addition, the obtained flat-sheet membranes characteristics including surface morphology, cross-section structure, thermal decomposition, porosity, pore size and pure water flux, were investigated. CNs filled membranes were also evaluated for fractionation of direct dye/NaCl binary mixture. Results reveal that, two stages of phase separation process are observed in CNs filled solution, in which the early stage can initiate with lower water content. This leads to fabrication of more porous membranes with longer finger-like cavities which were confirmed by FESEM analysis of the membranes. Results of TGA reveal that, two weight loss steps forms during decomposition process of CNs filled membranes. It was also observed that addition of 1.5 wt.% CNs into polymer solution increases water permeability from 20 to 90 L/m2 h. Application of 1.5 wt.% CNs filled membranes for fractionation of binary mixture containing direct red 23 (1 g/l) and NaCl (40 g/l) revealed that dye rejection and salt penetration percentages of obtained membranes are 98 % and 97 % respectively. Results confirm the potential of CNs filled membrane as a novel and promising approach for highly efficient fractionation of salt/dye mixtures, owning to its fabrication simplicity and perfect structural features.

Tailoring the hierarchical porous structure within polyethersulfone/cellulose nanosheets mixed matrix membrane to achieve efficient dye/salt mixture fractionation

Fatemeh Lessan

Papers

A novel durable flame-retardant cotton fabric using sodium hypophosphite, nano TiO2 and maleic acid

Effect of [EMIM][BF4] ionic liquid on the properties of ultrafiltration membranes

Phase separation and performance of polyethersulfone/cellulose nanocrystals membranes

Nano-TiO2/maleic acid/triethanol amine/sodium hypophosphite colloid on cotton to produce cross-linking and self-cleaning properties

Tailoring the hierarchical porous structure within polyethersulfone/cellulose nanosheets mixed matrix membrane to achieve efficient dye/salt mixture fractionation