Microwave-assisted esterification of bleached and unbleached cellulose nanofibers

Microwave-assisted synthetic pathway was explored for the sustainable esterification of cellulose nanofibers (CNFs) using an aromatic amine compound. For this purpose, nanofibers were isolated from unbleached and bleached eucalyptus pulp through the homogenization process. The chemical composition, the structural properties, the morphology, and the thermal properties of the extracted nanofibers were investigated. para-aminobenzoic acid (PABA) was employed to esterify CNFs's aliphatic hydroxyl groups. FTIR and 13C NMR spectroscopy confirmed the success of the chemical modification. The structural characterization of the cellulose nanofibers and lignocellulose nanofibrils esterified (CNF-E and LCNF-E) confirmed the grafting of the aromatic amine counterparts onto CNFs's surface. The thermogravimetric technique assessed the thermal stability of the nanofibrils. The thermal properties were affected by the esterification resulting in a significant improvement of the char yield (CR) compared to the original CNFs (from CR≈ 10% to > 20%). Finally, this sustainable chemical pathway increases CNFs's functionality by introducing ester and aromatic amine functionalities, making LCNF-E and CNF-E sustainable platforms for further smart applications.The authors wish to acknowledge financial support of the Basque Government (IT1498-22) and the University of the Basque Country (PIF21/52 and COLAB20/04). E.R. wants to acknowledge the tenure track position "Bois: Biobased materials" part of E2S UPPA supported by the "Investissements d'Avenir" French program managed by ANR [ANR-16-IDEX-0002]. The authors would like to acknowledge the technical and human assistance received from SGIker [UPV/ EHU/ERDF, EU], Spain. The authors would also like to thank Antoine Adjaoud for the scientific discussion

Sonochemical oxidation of technical lignin to obtain nanoparticles with enhanced functionality

Kraft lignin (KL) was treated by employing mild oxidation conditions enhanced by ultrasound irradiation (US) for obtaining more functionalized particles, avoiding the undesired side reactions of degradation and depolymerization. The aim was to obtain products with plausible value for applications with a greater potential market, enabling the introduction of low-cost bio-based materials for technically advanced applications. In the present work, KL was oxidized in alkaline media, applying low temperatures (30–60 °C), short times (15 to 60 min), and US waves (20 kHz). The influence of incorporating hydrogen peroxide (H2O2) as an oxidizing agent was also studied, as well as the chemical composition, physicochemical, thermal, and morphological properties of the final lignin particles. It was observed from Quantitative Acid Hydrolysis (QAH), Elemental Analysis (EA), and molecular weights (Mw) that oxidized lignin particles (OxL) did not suffer any major degradation. Other techniques used to determine physicochemical properties, such as Fourier Transformed Infrared (FTIR), 31 Phosphorous Nuclear Magnetic Resonance (31P NMR), or Ultraviolet–visible (UV-vis) methods, corroborated oxidation reactions, evident by the increment of carboxylic groups. The most noticeable difference, however, was observed when the stability and morphology of the particles were observed by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Some conditions greatly promoted the formation of more stable and nanosized particles. The best conditions were the mildest but with the highest reaction times (no addition of H2O2, 30 °C and 60 minutes). Moreover, all reactions had good recovery yields, above 70% of the original lignin.The authors would like to acknowledge the Basque Government for the financial support of this research through project IT1498-22 and grant PIF19-183. E. R. wants to acknowledge the tenure track position “BOIS” part of E2S UPPA supported by the “Investissements d'Avenir” French program managed by ANR (ANR-16-IDEX-0002). The authors thank for the technical and human support provided by SGIker (UPV/EHU/ERDF, EU)

Effect Of Reaction Conditions On The Surface Modification Of Cellulose Nanofibrils With Aminopropyl Triethoxysilane

Nine different surface modifications of cellulose nanofibrils (CNF) with 3-aminopropyl triethoxysilane (ATS) by using three different solvent systems (water, ethanol, and a mixture of both) were investigated. The effect of reaction conditions, such as silane to cellulose ratio and solvent type were evaluated to determine their contribution to the extent of the silane modification. Nanofibril properties were evaluated by infrared spectroscopy, powder X-ray diffraction, surface free energy, thermogravimetry, C-13 and Si-29 nuclear magnetic resonance, and electronic microscopy. The influence of the solvent in the solvolysis of the silane was reflected in the presence or absence of ethoxy groups in the silane. On the other hand, whereas the surface modification was increased directly proportionally to silane ratio on the reaction, the aggregation of nanofibrils was also increased, which can play a negative role in certain applications. The increment of silane modification also had substantial repercussions on the crystallinity of the nanofibrils by the addition of amorphous components to the crystalline unit; moreover, silane surface modifications enhanced the hydrophobic character of the nanofibrils.The authors would like to acknowledge the Basque Government (IT1008-16) and Mexican Council of Science and Technology (CONACyT), through scholarship No. 216178 for financially supporting this work. This article was also made in frame of the "EFOP-3.6.1-16-2016-00018-Improving the role of research + development + innovation in the higher education through institutional developments assisting intelligent specialization in Sopron and Szombathely"

Assessment of Bleached and Unbleached Nanofibers from Pistachio Shells for Nanopaper Making

Cellulose and lignocellulose nanofibrils were extracted from pistachio shells utilizing environmentally friendly pulping and totally chlorine-free bleaching. The extracted nanofibers were used to elaborate nanopaper, a continuous film made by gravimetric entanglement of the nanofibers and hot-pressed to enhance intramolecular bonding. The elaborated nanopapers were analyzed through their mechanical, optical, and surface properties to evaluate the influence of non-cellulosic macromolecules on the final properties of the nanopaper. Results have shown that the presence of lignin augmented the viscoelastic properties of the nanopapers by ≈25% compared with fully bleached nanopaper; moreover, the hydrophobicity of the lignocellulose nanopaper was achieved, as the surface free energy was diminished from 62.65 to 32.45 mNm−1 with an almost non-polar component and a water contact angle of 93.52°. On the other hand, the presence of lignin had an apparent visual effect on the color of the nanopapers, with a ΔE of 51.33 and a ΔL of −44.91, meaning a substantial darkening of the film. However, in terms of ultraviolet transmittance, the presence of lignin resulted in a practically nonexistent transmission in the UV spectra, with low transmittance in the visible wavelengths. In general, the presence of lignin resulted in the enhancement of selected properties which are desirable for packaging materials, which makes pistachio shell nano-lignocellulose an attractive option for this field.The authors would like to acknowledge the University of the Basque Country UPV/EHU for financially supporting this work. E.R. wishes to acknowledge the tenure track position “Biobased materials” part of E2S UPPA supported by the “Investissements d’Avenir” French program managed by ANR (ANR-16-IDEX-0002). N.I. wishes to acknowledge the Basque Government for financial support through the PIF19-183 contract

Fine-tune of lignin properties by its fractionation with a sequential organic solvent extraction

[EN] In this work, different lignins were obtained from two different extraction methods (kraft and organosolv) but from the same raw material (Eucalyptus globulus sp.). They were subsequently fractionated to determine the differences of each extraction method and their corresponding physicochemical properties found in fractionation sequence and obtained fractions. The goal of the fractionation was to obtain lignin fractions with narrower molecular weight distribution and lower polydispersity index (PI). The solvent sequence was designed based on the environmental friendly properties, health and safety assessments of the selected organic solvents: (methanol (MeOH), ethanol (EtOH), propan-2-one (DMK), ethyl acetate (EtOAc), propan-1-ol (nPrOH), propan-2-ol (iPrOH), butan-2-one (MEK), and butan-1-ol (tBuOH)). The different fractions obtained were characterised to determine their chemical structure by several analytical techniques, such as Fourier Transformed Infrared Spectroscopy (FTIR), Ultraviolet (UV), Phosphorus-31 Nuclear Magnetic Resonance (P-31 NMR), Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS), Thermogravimetric analysis (TGA), and Differential scanning calorimetry (DSC). In addition, Gel Permeation Chromatography (GPC) was used to obtain the molecular weight distribution. This study showed an effective method for obtaining homogeneous lignins with specific structures and properties depending on the solvent and molecular weight attained. Moreover, the method designed was found to be effective regardless of the lignin extraction process employed; besides, various lignin fractions were obtained which were different from each other, having specific target applications depending on their structure and chemical properties, ranging from small molecules with abundant reactive sites to act as active materials or copolymer reagents for many applications, to larger and more inactive molecules with higher thermal resistivity.The authors would like to acknowledge the Basque Government for the financial support of this research through project IT1008-16 and grant PIF19-183. Furthermore, E. R. wants to acknowledge the tenure track position "BOIS" part of E2S UPPA supported by the "Investisse-ments d'Avenir" French program managed by ANR (ANR-16-IDEX-0002)

Understanding the effects of copolymerized cellulose nanofibers and diatomite nanocomposite on blend chitosan films

Chitosan films lack various important physicochemical properties and need to be supplemented with reinforcing agents to bridge the gap. Herein, we have produced chitosan composite films supplemented with copolymerized (with polyacrylonitrile monomers) cellulose nanofibers and diatomite nanocomposite at different concentrations. The incorporation of CNFs and diatomite enhanced the physicochemical properties of the films. The mechanical characteristics and hydrophobicity of the films were observed to be improved after incorporating the copolymerized CNFs/diatomite composite at different concentrations (CNFs: 1%, 2% and 5%; diatomite: 10% and 30%). The antioxidant activity gradually increased with an increasing concentration (1-5% and 10-30%) of copolymerized CNFs/diatomite composite in the chitosan matrix. Moreover, the water solubility decreased from 30% for chitosan control film (CH-0) to 21.06% for films containing 30% diatomite and 5% CNFs (CNFs-D30-5). The scanning electron micrographs showed an overall uniform distribution of copolymerized CNFs/diatomite composite in the chitosan matrix with punctual agglomerations.R. FM. would like to express her gratitude to the Department of Economic Development and Infrastructures of the Basque Government (scholarship of young researchers training) for supporting this research financially. E.R. wants to acknowledge the tenure track position "Biobased materials" part of E2S UPPA supported by the "Investissements d'Avenir" French program managed by ANR (ANR16IDEX0002) . The authors would like to acknowledge the technical and human support provided by SGIker (UPV/EHU/ERDF.EU) and Biotechnology Institute, Ankara University, Turkey. Documen

Cellulose Nanocrystal Membranes as Excipients for Drug Delivery Systems

In this work, cellulose nanocrystals (CNCs) were obtained from flax fibers by an acid hydrolysis assisted by sonochemistry in order to reduce reaction times. The cavitation inducted during hydrolysis resulted in CNC with uniform shapes, and thus further pretreatments into the cellulose are not required. The obtained CNC exhibited a homogeneous morphology and high crystallinity, as well as typical values for surface charge. Additionally, CNC membranes were developed from CNC solution to evaluation as a drug delivery system by the incorporation of a model drug. The drug delivery studies were carried out using chlorhexidine (CHX) as a drug and the antimicrobial efficiency of the CNC membrane loaded with CHX was examined against Gram-positive bacteria Staphylococcus aureus (S. Aureus). The release of CHX from the CNC membranes is determined by UV-Vis. The obtaining methodology of the membranes proved to be simple, and these early studies showed a potential use in antibiotic drug delivery systems due to the release kinetics and the satisfactory antimicrobial activity.The authors would like to acknowledge the Department of Education, Universities and Investigation of the Basque Government (project IT1008-16), the Federal Agency for Support and Evaluation of Graduate Education (CAPES) through process BEX 8710/14-7, the Mexican Council of Science and Technology (CONACyT) through scholarship 216178 and theBrazilian National Council for Scientific and Technological Development for financial support through CNPq (# 482251/2013-1) for financially supporting this work. The authors also thank Maite Insausti and Oihane Arriortua for their kind help and support with Nanosizer and SGIker of the University of the Basque Country UPV/EHU for technical and human support provided with XRD, NMR and AFM characterizations and Altair Faes of the Regional Center of Oncology of the Federal University of Pelotas (UFPel) for the use of the equipment Eldorado 78

5to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

El V Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2019, realizado del 6 al 8 de febrero de 2019 y organizado por la Universidad Politécnica Salesiana, ofreció a la comunidad académica nacional e internacional una plataforma de comunicación unificada, dirigida a cubrir los problemas teóricos y prácticos de mayor impacto en la sociedad moderna desde la ingeniería. En esta edición, dedicada a los 25 años de vida de la UPS, los ejes temáticos estuvieron relacionados con la aplicación de la ciencia, el desarrollo tecnológico y la innovación en cinco pilares fundamentales de nuestra sociedad: la industria, la movilidad, la sostenibilidad ambiental, la información y las telecomunicaciones. El comité científico estuvo conformado formado por 48 investigadores procedentes de diez países: España, Reino Unido, Italia, Bélgica, México, Venezuela, Colombia, Brasil, Estados Unidos y Ecuador. Fueron recibidas un centenar de contribuciones, de las cuales 39 fueron aprobadas en forma de ponencias y 15 en formato poster. Estas contribuciones fueron presentadas de forma oral ante toda la comunidad académica que se dio cita en el Congreso, quienes desde el aula magna, el auditorio y la sala de usos múltiples de la Universidad Politécnica Salesiana, cumplieron respetuosamente la responsabilidad de representar a toda la sociedad en la revisión, aceptación y validación del conocimiento nuevo que fue presentado en cada exposición por los investigadores. Paralelo a las sesiones técnicas, el Congreso contó con espacios de presentación de posters científicos y cinco workshops en temáticas de vanguardia que cautivaron la atención de nuestros docentes y estudiantes. También en el marco del evento se impartieron un total de ocho conferencias magistrales en temas tan actuales como la gestión del conocimiento en la universidad-ecosistema, los retos y oportunidades de la industria 4.0, los avances de la investigación básica y aplicada en mecatrónica para el estudio de robots de nueva generación, la optimización en ingeniería con técnicas multi-objetivo, el desarrollo de las redes avanzadas en Latinoamérica y los mundos, la contaminación del aire debido al tránsito vehicular, el radón y los riesgos que representa este gas radiactivo para la salud humana, entre otros

Obtention and functionalization of cellulose nanofibers from agave tequilana weber var.azul

213 p.El presente trabajo busca dar una alternativa a la gestión de los subproductos derivados de la industria destiladora del tequila en el occidente mexicano, Se han realizado investigaciones orientadas a determinar la mejor manera de explotar el potencial material que suponen los subproductos de la industria del tequila (hojas y bagazo). Se estudiaron los métodos existentes que han dado resultados positivos en la elaboración de nanopartículas a partir de otras plantas con características similares y que representan procesos de bajo impacto ambiental como el blanqueo totalmente libre de cloro y la extracción por solventes orgánicos. Una vez obtenidas las nanopartículas, éstas son modificadas mediante reacciones que agregan a los grupos OH diferentes grupos funcionales para modificar las propiedades de la celulosa, dichas modificaciones pueden estar enfocadas a la mejora de propiedades hidrófobas, así como para mejorar su interacción en matrices poliméricas. Los principales grupos utilizados son aminosilanos, y ácidos grasos

Obtention and functionalization of cellulose nanofibers from agave tequilana weber var.azul

213 p.El presente trabajo busca dar una alternativa a la gestión de los subproductos derivados de la industria destiladora del tequila en el occidente mexicano, Se han realizado investigaciones orientadas a determinar la mejor manera de explotar el potencial material que suponen los subproductos de la industria del tequila (hojas y bagazo). Se estudiaron los métodos existentes que han dado resultados positivos en la elaboración de nanopartículas a partir de otras plantas con características similares y que representan procesos de bajo impacto ambiental como el blanqueo totalmente libre de cloro y la extracción por solventes orgánicos. Una vez obtenidas las nanopartículas, éstas son modificadas mediante reacciones que agregan a los grupos OH diferentes grupos funcionales para modificar las propiedades de la celulosa, dichas modificaciones pueden estar enfocadas a la mejora de propiedades hidrófobas, así como para mejorar su interacción en matrices poliméricas. Los principales grupos utilizados son aminosilanos, y ácidos grasos