Enzyme-mediated in situ functionalization of cotton fibers was studied using laccase. Caffeic acid and morin were used as reactive phenolic substrates for laccase and further employed to the modification of fiber surfaces. Laccase-mediated oxidation and polymerization reactions of caffeic acid were monitored by ultraviolet–visible spectroscopy. During the wetting process, initial cationization of fiber surfaces using poly(diallyldimethylammonium chloride) followed by enzymatic treatment with phenolic substrates resulted ineffective polymer grafting evidenced by high color stability. Changes of fiber surface properties by polymer grafting, such as morphology and hydrophilicity/hydrophobicity, were tested using scanning electron microscopy and gravimetric absorption tests. An acceptable level of color resistance to washing stress was obtained on caffeic acid treated samples, and a high l...

Chitosan is obtained from alkaline deacetylation of chitin, and acetamide groups are transformed into primary amino groups during the deacetylation. The diverse biological activities of chitosan and its derivatives are extensively studied that allows to widening the application fields in various sectors especially in biomedical science. The biological properties of chitosan are strongly depending on the solubility in water and other solvents. Deacetylation degree (DDA) and molecular weight (MW) are the most decisive parameters on the bioactivities since the primary amino groups are the key functional groups of chitosan where permits to interact with other molecules. Higher DDA and lower MW of chitosan and chitosan derivatives demonstrated higher antimicrobial, antioxidant, and anticancer capacities. Therefore, the chitosan oligosaccharides (COS) with a low polymerization degree are recei...

The construction industry is responsible not only for the consumption of huge amounts of natural resources but also for the emission of large quantities of CO2. Geopolymers have emerged as an environmentally friendly alternative for conventional construction materials since they can be produced from industrial wastes. Similarly to ordinary concrete, geopolymers can also improve their mechanical properties when reinforced with fibers. This paper presents a review of recent advances in the production of natural fiber-reinforced geopolymers produced from industrial by-products and waste materials as promising sustainable construction materials. Regarding the use of industrial wastes, this paper reports the use of fly ash, ground granulated blast furnace slag, construction and demolition wastes and mine tailings for the production of high strength geopolymers. At the same time, a survey of s...

The construction industry is responsible not only for the consumption of huge amounts of natural resources but also for the emission of large quantities of CO2. Geopolymers have emerged as an environmentally friendly alternative for conventional construction materials since they can be produced from industrial wastes. Similarly to ordinary concrete, geopolymers can also improve their mechanical properties when reinforced with fibers. This paper presents a review of recent advances in the production of natural fiber-reinforced geopolymers produced from industrial by-products and waste materials as promising sustainable construction materials. Regarding the use of industrial wastes, this paper reports the use of fly ash, ground granulated blast furnace slag, construction and demolition wastes and mine tailings for the production of high strength geopolymers. At the same time, a survey of s...

“Esta nueva tecnología permitirá, además de los dos frentes mencionados, incursionar en el desarrollo de una metodología integral de construcción sismorresistente seriada por impresión 3D de viviendas y edificaciones civiles