Roberto Aguado

• PhD
• Invited lecturer at University of Girona

Spherical selenium nanoparticles (Se NPs) were synthesized by green chemical reduction method using biocompatible chitosan (CS) or as reported herein for the first time, cationic cellulose nanofibers (CCNFs) as stabilizers. CNFs were cationized using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), followed by high-pressure homogeniz...

This study presents a novel equation that obtains the intrinsic flexural modulus of a natural fiber from its microfibril angle (MFA) and its crystalline cellulose content, once having estimated both parameters from X‐ray diffraction (XRD). The percentage of crystalline cellulose was estimated as the content of cellulose times the crystallinity inde...

The increase of non-native species in the seas and eutrophication cause accumulation of seaweed and marine plants on coasts that become waste. Marine biomass residues are abandoned or sent to landfills at considerable cost. The aim of this work is to revalue tidal waste as a cellulosic material. Cellulose was isolated using minimal environmental im...

While cationic cellulose has yet to find a place in the paper industry, manufacturers show certain interest in a more recent material: cellulose nanofibers (CNFs), generally with negative surface charge. This work suggests both to be combined to increase the mechanical properties of recycled paper while preventing the use of synthetic polyelectroly...

Composites based on polylactic acid (PLA) were developed, using lignocellulosic nanofibers (LCNF) dispersed in polyethylene glycol (PEG). To evaluate the impact of LCNF sources, suspensions were prepared from different pulps, including only cellulose; other with cellulose and hemicellulose; and cellulose, hemicellulose, and lignin. The PLA/PEG rati...

Este segundo volumen de la Red NANOCELIA se enfoca en compartir las experiencias de países iberoamericanos en la investigación, desarrollo y transferencia de la nanocelulosa. La publicación se estructura en dos partes fundamentales: la primera presenta trabajos concretos realizados por los grupos miembros de la Red, mientras que en un Anexo se exhi...

Although cellulosic materials have been used as stabilizing agents for oil-in-water emulsions since the 1980s, their properties and the underlying mechanism are not universal regardless of the dispersed phase or of the treatments on cellulose. One case of unconventional organic phase is acetic acid-containing chloroform, which is known to be a good...

The present work reveals the potential application of dialdehyde and carboxylated nanocellulose for the in-situ reduction of Ag⁺ and immobilization as silver nanoparticles (AgNPs) on cellulose surfaces. Tollens’ reagent (Ag(NH3)2OH) at concentrations ranging from 5·10–3 to 10–1 M was incorporated in both dialdehyde cellulose (DAC) and dialdehyde-mo...

This article evaluates two processes, wet milling and chemical depolymerization, for the end-of-life of wood waste in terms of environmental performance (ex ante life cycle assessment), energy balance, and economic analysis of the operating costs. Cellulose, hemicellulose, and lignin are essential components with numerous applications. The study pr...

The regioselective oxidation of the primary hydroxyl groups of cellulose, usually mediated by the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical (TEMPO), is highly popular in the scientific literature. However, the lack of efficient monitoring techniques imposes a severe limitation to its upscaling. This work involves a portable, user-friendly nea...

The extensive use of non‐biodegradable bioplastics and fossil‐based plastics in food packaging presents a significant environmental challenge. Consequently, there has been a growing interest in exploring agricultural biomass as a potential source for formulating biocomposites for packaging due to the substantial amount of lignocellulosic residue ge...

Membranes find applications across a wide spectrum of industries, including water treatment, energy production, and biomedicine. In this study, nonwoven membranes were fabricated using cellulose acetate (CA) as the primary component, with varying percentages of cellulose nanofibers (CNFs) embedded as reinforcement. These CNFs were prepared through...

The transition towards a sustainable cellulose industry needs more environmentally friendly technologies, including the use of lignocellulosic waste as alternative raw materials. This work shows the potential of dead biomass from the Andalusian Mediterranean coastline to obtain cellulosic pulp. With this purpose, predominant species in onshore resi...

This study aims to provide a comprehensive understanding of the key factors influencing the rheological behavior and the mechanisms of natural polyelectrolyte complexes (PECs) as floccula-tion agents for cellulose microfibers (CMFs) and nanofibers (CNFs). PECs were formed by combining two polyelectrolytes: xylan (Xyl) and chitosan (Ch), at differen...

This work reports on the development of nanocomposites based on poly(3- hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] and nanohydroxyapatite (nHA) for the development of scaffolds by means of a two-stage extrusion process followed by a 3D printing process. Tensile test samples were produced for the characterization of the materials. Each...

Complexes of lanthanide ions, such as Eu(III) (red light emission) and Tb(III) (green light emission), with proper ligands can be highly luminescent and color-tunable, also attaining yellow and orange emission under UV radiation. The ligands employed in this work were poly(sodium acrylate), working as polymeric matrix, and 1,10-phenanthroline, taki...

Beeswax is a bio-sourced, renewable, and even edible material that stands as a convincing option to provide paper-based food packaging with moisture resistance. Nonetheless, the difficulty of dispersing it in water limits its applicability. This work uses oxidized, negatively charged cellulose nanofibers along with glycerol to stabilize beeswax-in-...

Composite materials containing natural reinforcement fibers, generally called biocomposites, have attracted the interest of both researchers and manufacturers, but the most environmentally advantageous combinations include a bio-based matrix, as well. With this in mind, a poly(lactic acid) (PLA) matrix was reinforced with natural fibers from hemp,...

The transition towards a sustainable cellulose industry needs more environmentally friendly technologies that include the use of less polluting processes and alternative raw materials. This work shows the potential of tidal waste from the Andalusian Mediterranean coastline as cellulosic material to obtain cellulosic pulp. With this purpose, predomi...

The use of dithizone (DTZ) for colorimetric heavy-metal detection is approximately one century old. However, its pending stability issues and the need for simple indicators justify further research. Using cellulose nanofibers, we attained DTZ-containing emulsions with high stability. These emulsions had water (at least 95 wt %) and acetic acid (1-8...

Composites from polypropylene (PP) reinforced with hemp strands (HS) are prepared in the current work with the aim of deepening on the influence of this reinforcement on the impact performance of these specific composites. Despite all the research conducted in this field, the effect of this natural reinforcement on the absorbed energy during crack...

Cellulose micro- and nanofibers (CNFs) are commonly regarded as "greener" than petro-based materials. The high energy input that their production still demands, along with the use of chemicals or heat in some pretreatments, asks for a critical view. This paper attempts a life cycle assessment of CNFs produced from bleached hardwood kraft pulp via t...

The growing demand for plant fiber-reinforced composites offers new opportunities to compete against glass fiber (GF)-reinforced composites, but their performance must be assessed, revised, and improved as much as possible. This work reports on the production and the flexural strength of composites from polypropylene (PP) and hemp strands (20–50 wt...

The compatibility between poly(lactic acid) (PLA) and natural fibers to develop bio-sourced, recyclable, and biodegradable composites remains a commonplace issue. This work highlights that, at least in the case of hemp, pulping and bleaching towards delignified short fibers attained remarkable improvements over untreated hemp strands. This approach...

The present work aims at glimpsing the rate-determinant process parameters of TEMPO-mediated oxidation of bleached kraft cellulose for developing kinetic models and real-time monitoring tools. This may contribute to the scaling up of this reaction, frequently used as precursor of the production of cellulose nanofibers. For this, the effect of tempe...

Measurements of nanocellulose size usually demand very high-resolution techniques and tedious image processing, mainly in what pertains to the length of nanofibers. Aiming to ease the process, this work assesses a relatively simple method to estimate the dimensions of nanocellulose particles with an aspect ratio greater than 1. Nanocellulose suspen...

The development of new materials is currently focused on replacing fossil-based plastics with sustainable materials. Obtaining new bioplastics that are biodegradable and of the greenest possible origin could be a great alternative for the future. However, there are some limitations—such as price, physical properties, and mechanical properties—of th...

La eutrofización se produce debido a una acumulación excesiva de algas y fanerógamas marinas en las costas de las playas. Debido a ello, tiene lugar un aumento del número de insectos, nematodos y bacterias capaces de producir problemas sanitarios, medioambientales y económicos que afectan negativamente al turismo. Una alternativa sostenible a su re...

Cationic cellulose, despite its long history, has yet to find a place in the paper industry. However, recent research is evaluating the potential of its nanoscale forms. Likewise, the processes of Western manufacturers are optimized for wood pulps, relegating non-wood crops to specific products that, as also proposed by current research, could incl...

Food packaging manufacturers often resort to lamination, typically with materials which are neither non-biodegradable nor biobased polymers, to confer barrier properties to paper and cardboard. The present work considers a greener solution: enhancing paper’s resistance to moisture, grease, and air by aqueous coating suspensions. For hydrophobizatio...

Predictive monitoring of two key properties of nanocellulose, aspect ratio and yield of nanofibrillation, would help manufacturers control and optimize production processes, given the uncertainty that still surrounds their influential factors. For that, 20 different types of cellulosic and lignocellulosic micro/nanofibers produced from spruce and p...

The use of micro-/nanofibrillated celluloses (M/NFCs) is often considered for the enhancement of paper properties, while it is still challenging to use them in lower weight gain coatings. This work explores how they might be used on the paper surface to improve the printing quality. In this regard, M/NFCs were produced using different pre-treatment...

Despite changes in optical and printing properties, the applied coating components on the paper surface have a significant impact on the surface chemistry of office paper. Depending on the use, such as ink penetration for printing and writing papers, an optimal hydrophobic and hydrophilic balance may be beneficial. In this study, several coating co...

In this work we described the preparation of smart anticounterfeit labels. They are obtained by dipping cellulose paper strips in chromogenic polymer dissolutions. Depending on the selected polymer, up to a maximum of 12 possibilities, the labels can turn into different colors after being soaked with an aqueous solution of NaNO2 and HCl and a NaOH...

In this work a wide sample analysis, under similar conditions, has been carried out and a calibration strategy based on a careful selection of input variables combined with sensitivity analysis has enabled us to build accurate neural network models, with high correlation (R > 0.99), for the prediction of the aspect ratio of micro/nanofiber products...

The current need to develop more sustainable processes and products requires the study of new materials. In the field of plastic materials, the need to develop 100% bio-based materials that meet market requirements is evident. In this sense, the present work aims to explore the potential of rapeseed waste as a reinforcement of a bio-based plastic m...

As cationic cellulose, despite its long history, has yet to find a place in the paper industry, recent research is assessing the potential of its nanoscale forms. We combined this trend with the existing knowledge of the strong adsorption of poly(diallyldimethylammonium chloride) (polyDADMAC) on cellulosic fibers, which can be deemed a non-covalent...

Given the competitiveness in the tissue paper market, manufacturers are continuously seeking eco-friendly options to improve its properties. This work highlights the incorporation in tissue paper of fibrous formulations of deoxyribonucleic acid (DNA), taking advantage of the extremely versatile functionality of this macromolecule, which is, besides...

We present a feasible method to produce coated papers with long-lasting presence of natural active compounds. First, the composition of essential oils from Eucalyptus globulus was analyzed by gas chromatography-mass spectrometry (GC-MS), revealing high proportions of eucalyptol (73 %) and α-pinene (15 %) in the case of the leaves, and sesquiterpeno...

The current trends in micro-/nanofibers offer a new and unmissable chance for the recovery of cellulose from non-woody crops. This work assesses a technically feasible approach for the production of micro- and nanofibrillated cellulose (MNFC) from jute, sisal and hemp, involving refining and enzymatic hydrolysis as pretreatments. Regarding the latt...

Although it is well-known that nitroaromatic compounds quench the fluorescence of different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles, the potential of paper as a substrate for those macromolecules can be further developed. This work undertakes this task, impregnating paper strips with a fluorene-phenylene...

Competitiveness in the market for tissue paper, the only paper grade whose consumption increased during 2020 in Europe, requires seeking viable options to continuously improve its properties. This work explores the combination of gum Arabic, which is a naturally found, biodegradable, cheap and versatile heteropolymer, with bleached cellulosic pulps...

Tissue paper was the only paper grade whose consumption increased during 2020 in Europe. In a highly competitive context, this work explores a strategy based on bisacrylamide cross-linkers and poly(vinyl alcohol) (PVA), seeking to enhance the water uptake of pulps for tissue paper and the key properties of the resulting tissue sheets: water absorpt...

This bibliometric study encompasses all publications between 2000 and 2020 on the production of cellulose-containing food packaging, often proposed as an alternative to petro-based materials. Results show a fast-growing interest in this area, especially during the last decade, with 1029 documents published in high-impact journals. In a topic where...

Partly inspired by the concept of masterbatch in plastics manufacturing, we developed a strategy to improve the technical viability, the economic feasibility, and the environmental performance of lignocellulosic micro-/nanofibers. Instead of investing strenuous efforts in dewatering and/or drying nanocellulose suspensions to maximize their consiste...

While the potential of cellulose nanofibers to enhance the mechanical and barrier properties of paper is well-known, there are many uncertainties with respect to how to apply them. In this study, we use not only bulk addition of micro-/nanofibers and bar coating with oxidized nanofibers, but also a combination of these and, as a novel element, elec...

The synthesis and preparation of 12 chromogenic polymers used to build an intelligent label for security paper applications are described. The process involves coating paper sheets with the polymers. Depending on the number of different polymers used in a combinatory way, a maximum of 12¹² combinations is possible, thus creating a matrix that is pr...

In this study, Young’s modulus of henequen fibers was estimated through micromechanical modeling of polypropylene (PP)-based composites, and further corroborated through a single filament tensile test after applying a correction method. PP and henequen strands, chopped to 1 mm length, were mixed in the presence of maleic anhydride grafted polypropy...

Improving the printability of paper is still a relevant challenge, despite the fast development of digital communications. While it is well-known that cationic starches enhance ink density, their commercial paper-grade forms are limited to ethers with low degree of substitution. This work addresses the underexplored potential of highly substituted...

The specific surface area (SSA) of cellulosic or lignocellulosic fibers is seldom reported in the recent literature on papermaking, despite its close relation with the degree of refining and other key pulp properties. Amidst outdated assays (Pulmac permeability test) and methods that, while accurate, are of doubtful usefulness for papermaking purpo...

In this work, the brown alga Dictyota dichotoma was explored as a new reinforcing material for papermaking. Performing the typical chemical tests for cellulosic substrates on D. dichotoma evidenced large amounts of ethanol:benzene extractable substances (7.2%) and ashes, algae-specific results. Also, even if lipophilic compounds are removed, brown...

Ball milling of starch with methyl betainate was performed to synthesize starch betainate. Betaine hydrochloride was first esterified using thionyl chloride in methanol, attaining a yield of 84%. Prior to the reaction in the ball mill, starch was pretreated using α-amylase enzyme, cooked at high temperature in water, regenerated using absolute etha...

Not surprisingly, cellulose-based agents for wastewater treatments, and more precisely for coagulation-flocculation processes, raise growing interest, boosted not only by the high availability, functionality, renewability, and biodegradability of cellulose, but also by the outstanding performance of their derivatives. The analysis of 460 publicatio...

This communication reports the use of gum Arabic (GA) to form highly soluble lanthanide-based complexes with RGB properties. GA is a biocompatible and inexpensive branched-chain polysaccharide with the main chain of (1-3)-β-Dgalactopyranosyl units and side chains containing L-arabinofuranosyl, L-rhamnopyranosyl, D-galactopyranosyl and D-glucopyrano...

Improving the printability of paper is still a relevant challenge, despite the fast development of digital communications. While it is well-known that cationic starches enhance ink density, their commercial paper-grade forms are limited to ethers with low degree of substitution. This work addresses the underexplored potential of highly substituted...

Far from being devoid of improvement, mechanical fibrillation benefits from high-yield pulping and refining to produce lignocellulosic micro- and nanofibers (LCMNFs). Spruce thermomechanical pulp was pretreated in a PFI mill to 10,000–30,000 revolutions and then passed, from 3 to 12 times and at 300–900 bar, through a high-pressure homogenizer. Mai...

Polysaccharide substrates loaded with antioxidant and antimicrobial compounds, effectively protected by cyclodextrin moieties, can be a long-lasting solution to confer certain properties to fabrics, paper and other materials. β-Cyclodextrin was attached to α-cellulose, bleached pulp and starch by a two-step esterification with a tetracarboxylic aci...

Transesterification of starch with methyl betainate was studied for the first time, both in aprotic media and in solid state, and both under alkaline and acidic conditions. Betaine hydrochloride was first esterified in methanol, attaining a conversion of 86%. Starch was then converted into starch betainate in either N,N-dimethylformamide or dimethy...

This communication considers the hypothesis that the functionalization of polysaccharides with β-cyclodextrin (β-CD) units improves their performance as carriers for bioactive compounds, slowing down the release rate to aqueous-alcoholic media.

This communication reports the development of a luminescent complex, capable of RGB-tunable emission under UV radiation, to be used as a security tag in paper industry.

Cationic starch (CS) can be obtained by attaching positively charged groups such as quaternaryamines, iminium, ammonium, sulfonium or phosphonium groups to the starch backbone. The reaction proceeds through the formation of ether or ester bonds between the hydroxyl groups of anhydrous glucose units of starch and the functional groups present in the...

Starch was functionalized with ceta-cyclodextrin and paper was subsequently coated with this derivative and with an essential oil from eucalyptus. The losses to air were evaluated by headspace-solid phase microextraction (HS-SPME), using a divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber, whose adsorbates were analyzed by GC-MS.

Chemical pollution of water has raised great concerns among citizens, lawmakers, and nearly all manufacturing industries. As the legislation addressing liquid effluents becomes more stringent, water companies are increasingly scrutinized for their environmental performance. In this context, emergent contaminants represent a major challenge, and the...

Starch and derivatives thereof have proven their usefulness in paper coating processes. Among these derivatives, cationic starch has been widely used in the paper industry as a flocculation, dispersion and ink fixing agent. In another context, nanoscale cellulosic materials have been shown to improve the strength, retention of fillers, the barrier...

Every year, millions of tonnes of dead biomass from algae and seagrasses are collected on the Mediterranean coasts. Posidonia oceanica is one of the most abundant species. In this work, leaves and rhizomes from this plant were pulped, alkalized, and cationized to make a value-added product. The main effects of five separate pulping variables, namel...

Functionalized paper solutions have attracted the attention of many research groups in the 21st century, given the low cost, availability, flexibility and biodegradability of paper. Despite this material has been manufactured for more than two thousand years, its traditional uses hardly go beyond writing, printing, cleaning and packaging. This over...

The large amount of cellulose found in Ulva sp. and its low percentage of lignin-like compounds make it an interesting raw material for partially substituting wood pulp to produce pulp and paper. This work shows the suitability of mild chemical treatments for papermaking using residual biomass from this green seaweed, harvested on the beaches, in o...

Cationized fibers and other kinds of chemically modified fibers impart many advantages in papermaking, but unfeasibly long reaction times are necessary to attain acceptable degrees of substitution, due to the low reactivity of bleached kraft pulps. In this work, different aqueous pretreatments were tested in order to activate cellulose towards a 60...