Composite electrospun membranes from cellulose nanocrystals, castor oil, and poly(ethylene terephthalate): Air permeability, thermal stability, and other relevant properties.

The study examined the use of cellulose nanocrystals (CNCs) in poly(ethylene terephthalate) (PET)/castor oil (CO) electrospun membranes, focusing on how CNCs influenced membrane properties for aerosol filtration applications. PET membranes were fabricated using 5 wt% and 10 wt% of CNCs and 2.5 wt% CO to assess its effectiveness as a compatibilizing agent, under a solution flow rate of 25.

Isotopic study for evaluating complex groundwater circulation patterns, hydrogeological zoning, and water-rock interaction in a Mediterranean coastal karst environment.

In this study groundwater provenance, circulation, and rock interaction processes have been assessed by cross processing the spatial distribution of chemical and isotopic signatures in freshwater with the hydrogeological features of the coastal karst carbonate aquifer of Murgia, located in the southeastern end of Italy, along the Adriatic Sea. Thanks to widespread groundwater quality monitoring (major, minor, and trace-element analyses) and multi-isotopic measures of O, H, Sr, and B, some assumptions about complex groundwater circulation patterns, hydrogeological zoning, and water-rock interaction have been drawn. Three sectors have been distinguished into the Adriatic side of the Murgia aquifer all fed by two main recharge areas located on the most elevated, inner side of the aquifer.

A comprehensive monitoring approach for a naturally anoxic aquifer beneath a controlled landfill.

The processes leading to high levels of arsenic (As), iron (Fe), and manganese (Mn) in groundwater, in a naturally reducing aquifer at a controlled municipal landfill site, are investigated. The challenge is to distinguish the natural water-rock interaction processes, that allow these substances to dissolve in groundwater, from direct pollution or enhanced dissolution of hydroxides as undesired consequences of the anthropic activities above. Ordinary groundwater monitoring of physical-chemical parameters and inorganic compounds (major and trace elements) was complemented by environmental isotopes of groundwater (tritium, deuterium, oxygen-18 and carbon-13) and dissolved gases (carbon-13 of methane and carbon dioxide and carbon-14 of methane).

Synthesis, Characterization, and Evaluation of the Antimicrobial Effects and Cytotoxicity of a Novel Nanocomposite Based on Polyamide 6 and Trimetaphosphate Nanoparticles Decorated with Silver Nanoparticles.

This study aimed to develop a polymeric matrix of polyamide-6 (P6) impregnated with trimetaphosphate (TMP) nanoparticles and silver nanoparticles (AgNPs), and to evaluate its antimicrobial activity, surface free energy, TMP and Ag release, and cytotoxicity for use as a support in dental tissue. The data were subjected to statistical analysis ( < 0.05).

Cellulose esters: Synthesis for further formation of films with magnetite nanoparticles incorporated.

This study investigated the homogeneous synthesis of cellulose acetate (CA) and propionate (CP) with varying degrees of substitution (DS) from sisal cellulose in a N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. These esters were used to prepare neat (CAF/CPF) and nanocomposite films (CAFFe/CPFFe) from prior synthesized magnetite nanoparticles (NPs, FeO, 5.1 ± 0.

Cellulose acylation in homogeneous and heterogeneous media: Optimization of reactions conditions.

The dependence of the DS on the acid anhydride/anhydroglucose unit ((RCO)O/AGU) molar ratio was correlated using second-order polynomials. The regression coefficients of the (RCO)O/AGU terms showed that increasing the length of the RCO group of the anhydride led to lower values of DS. For acylation under heterogeneous reaction conditions, the following were employed: acid anhydrides and butyryl chloride as acylating agents; iodine as a catalyst; N,N-dimethylformamide (DMF) as a solvent, pyridine, and triethylamine as solvents and catalysts.

Polyurethane films formation from microcrystalline cellulose as a polyol and cellulose nanocrystals as additive: Reactions favored by the low viscosity of the source of isocyanate groups used.

To simultaneously form films while synthesizing solvent-free and catalyst-free bio-based polyurethanes, hexamethylene diisocyanate trimer was selected as an isocyanate group source to produce a low-viscosity reaction medium for dispersing high contents of microcrystalline cellulose (MCC, polyol) and cellulose nanocrystals (CNC). Castor oil was used as an additional polyol source. Up to 80 % of the MCC was dispersed, producing a film exhibiting the highest T (72 °C), tensile strength (18 MPa), and Young's modulus (522.

A double pre-selection method for natural background levels assessment in coastal groundwater bodies.

To evaluate the chemical status of groundwater bodies (GWB) according to the European Groundwater Directive, EU Member States are required to take into account natural background levels (NBLs) where needed. Assessing the NBLs in coastal GWBs is complicated by seawater intrusion which can be amplified by groundwater withdrawals increasing the salinization of such groundwater systems. This paper proposes a new method for the NBLs assessment in coastal areas based on a double pre-selection (PS) with fixed/dynamic limits.

Cross-Linked and Surface-Modified Cellulose Acetate as a Cover Layer for Paper-Based Electrochromic Devices.

We studied the surface and microstructure of cellulose acetate (CA) films to tailor their barrier and mechanical properties for application in electrochromic devices (ECDs). Cross-linking of CA was carried out with pyromellitic dianhydride to enhance the properties relative to unmodified CA: solvent resistance (by 43% in acetone and 37% in DMSO), strength (by 91% for tensile at break), and barrier (by 65% to oxygen and 92% to water vapor). Surface modification via tetraethyl orthosilicate and octyltrichlorosilane endowed the films with hydrophobicity, stiffness, and further enhanced solvent resistance.

Cellulose nanocrystals: Pretreatments, preparation strategies, and surface functionalization.

Cellulose nanocrystals (CNCs) have attracted great interest from researchers from academic and industrial areas because of their interesting structural features and unique physicochemical properties, such as magnificent mechanical strength, high surface area, and many hydroxyl groups for chemical modification, low density, and biodegradability. CNCs are an outstanding contender for applications in assorted fields comprehensive of, e.g.

Hydrogel from all in all lignocellulosic sisal fibers macromolecular components.

The heterogeneous structure of lignocellulosic biomass makes it difficult to dissolve its main components (cellulose, hemicelluloses, and lignin) by solvent action with the aim of further applying the mixture of the biological macromolecules generated in the solvent medium. In the present study, the dissolution efficiency (DE) of lignocellulosic sisal fibers in the lithium chloride/dimethylacetamide solvent system (LiCl/DMAc) was evaluated for further application in the formation of hydrogels. Catalytic amounts of trifluoroacetic acid (TFA) were used in some experiments, which increased the DE from 40% to 90%.

Groundwater quality trend and trend reversal assessment in the European Water Framework Directive context: an example with nitrates in Italy.

Groundwater resources are of utmost importance in sustaining water related ecosystems, including humans. The long-lasting impacts from anthropogenic activities require early actions, owing to the natural time lag in groundwater formation and renewal. The European Union (EU) policy, within the implementation of the Water Framework Directive (WFD), requires Member States to identify and reverse any significant and sustained upward trend in the concentration of pollutants, defining specific protection measures to be included in the River Basin Management Plans (RBMP).

Bio-based electrospun mats composed of aligned and nonaligned fibers from cellulose nanocrystals, castor oil, and recycled PET.

Cellulose nanocrystals (CNCs), castor oil (CO), and recycled poly(ethylene terephthalate) (rPET), were used to add value to renewable raw materials and to a recycled polymer produced worldwide, producing mats composed of fibers on the nano- and submicrometric (ultrathin) scales through a sustainable process. Bio-based electrospun mats composed of aligned (rotary collector) and nonaligned (static collector) nanofibers/ultrathin fibers were produced from the electrospinning of solutions prepared from rPET (mixed with CO, CNCs, or CNCs/CO). The contact angle results showed that the CNC mat surfaces composed of nonaligned fibers were hydrophilic, and in contrast, these surfaces were hydrophobic when composed of aligned fibers.

Synthesis of bio-based polyurethanes from Kraft lignin and castor oil with simultaneous film formation.

Kraft lignin (KL) and castor oil (CO) were used as polyols in the synthesis of bio-based polyurethanes (PUs) in the absence of both solvents and catalysts at room temperature with simultaneous film formation. KL was purified (PKL), and both KL and PKL were fully characterized. CO was mixed with different percentages of PKL (0%, 10%, 30%, and 50%), as well as with polymeric methyl phenyl diisocyanate.

Investigating effects of high cellulase concentration on the enzymatic hydrolysis of the sisal cellulosic pulp.

The goal of this study was to investigate how the use of high concentration of cellulase may impact the properties of the substrate and the reaction medium during the enzymatic hydrolysis of the sisal pulp. Enzyme concentration of 0.9 mL g was considered for hydrolysis of a sisal cellulosic substrate, and the results were compared with previous ones using 0.

Renewable Resources and a Recycled Polymer as Raw Materials: Mats from Electrospinning of Lignocellulosic Biomass and PET Solutions.

Interest in the use of renewable raw materials in the preparation of materials has been growing uninterruptedly in recent decades. The aim of this strategy is to offer alternatives to the use of fossil fuel-based raw materials and to meet the demand for materials that are less detrimental to the environment after disposal. In this context, several studies have been carried out on the use of lignocellulosic biomass and its main components (cellulose, hemicelluloses, and lignin) as raw materials for polymeric materials.

Disentangling natural and anthropogenic impacts on groundwater by hydrogeochemical, isotopic and microbiological data: Hints from a municipal solid waste landfill.

Within human-impacted areas, high levels of inorganic compounds in groundwater are broadly and preventively attributed to local anthropogenic pollution, thoroughly disregarding geogenic natural background levels. Particularly in landfills, a proper evaluation of the significant adverse environmental effects should be completed through a detailed groundwater characterization, and appropriate reference values established prior to landfill onset. However, the monitoring network may lack a full hydrogeological representativeness of the site and of the background conditions of groundwater.

Nanostructured electrospun nonwovens of poly(ε-caprolactone)/quaternized chitosan for potential biomedical applications.

Blend solutions of poly(ε-caprolactone) (PCL) and N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride (QCh) were successfully electrospun. The weight ratio PCL/QCh ranged in the interval 95/5-70/30 while two QCh samples were used, namely QCh1 (DQ¯ = 47.3%; DPv¯ = 2218) and QCh2 (DQ¯ = 71.

Sodium lignosulfonate as a renewable stabilizing agent for aqueous alumina suspensions.

The macromolecule sodium lignosulfonate (SL) has been investigated as dispersing agent for aqueous alumina colloids as a renewable alternative to usual petrochemical stabilizing agents. Optimization of the SL concentration necessary to stabilize the alumina suspension at different pH values was determined by viscometer. The results showed that addition of 250 ppm of the total suspension mass led to about 70% viscosity reduction of the suspension, whereas zeta potential analysis revealed negative values for the SL suspensions throughout the pH range investigated, suggesting that the alumina particles were covered by negatively charged SL molecules.

Bio-based Films from Linter Cellulose and Its Acetates: Formation and Properties.

This paper describes the results obtained on the preparation of films composed of linter cellulose and the corresponding acetates. The acetylation was carried out in the LiCl/DMAc solvent system. Films were prepared from a LiCl/DMAc solution of cellulose acetates (degree of substitution, DS 0.

Dynamic mechanical thermal analysis of composite resins with CQ and PPD as photo-initiators photoactivated by QTH and LED units.

Objectives: The aim of this study was to evaluate the thermal and mechanical properties of the composite resins containing the photo-initiators camphorquinone (CQ) and/or phenyl-propanodione (PPD) when photoactivated with halogen lamp (XL2500/3M-ESPE), monowave (UltraBlueIS/DMC) and polywave (UltraLume5/Ultradent) LED units.

Materials And Methods: A blend of BisGMA, UDMA, BisEMA and TEGDMA was prepared with the same wt% of photo-initiators CQ and/or PPD and 65wt% of silaneted filler particles. Compression strength (CS), diametral tensile strength (DTS) and diametral modulus (DM) were tested.

Effect of acid concentration and pulp properties on hydrolysis reactions of mercerized sisal.

The influence of sulfuric acid concentration (H2SO4 5-25%, 100°C), crystallinity and fibers size on the hydrolysis reaction of sisal pulps were investigated, with the goal of evaluating both the liquor composition, as an important step in the production of bioethanol, and the residual non-hydrolyzed pulp, to determine its potential application as materials. Aliquots were withdrawn from the reaction media, and the liquor composition was analyzed by HPLC. The residual non-hydrolyzed pulps were characterized by SEM, their average molar mass and crystallinity index, and their size distribution was determined using a fiber analyzer.

Effect of different photo-initiators and light curing units on degree of conversion of composites.

The aim of this study was to evaluate: (i) the absorption of photo-initiators and emission spectra of light curing units (LCUs); and (ii) the degree of conversion (DC) of experimental composites formulated with different photo-initiators when activated by different LCUs. Blends of BisGMA, UDMA, BisEMA and TEGDMA with camphorquinone (CQ) and/ or 1-phenyl-1,2-propanedione (PPD) were prepared. Dimethylaminoethyl methacrylate (DMAEMA) was used as co-initiator.

Valorization of an industrial organosolv-sugarcane bagasse lignin: Characterization and use as a matrix in biobased composites reinforced with sisal fibers.

In the present study, the main focus was the characterization and application of the by-product lignin isolated through an industrial organosolv acid hydrolysis process from sugarcane bagasse, aiming at the production of bioethanol. The sugarcane lignin was characterized and used to prepare phenolic-type resins. The analysis confirmed that the industrial sugarcane lignin is of HGS type, with a high proportion of the less substituted aromatic ring p-hydroxyphenyl units, which favors further reaction with formaldehyde.

Biobased composites from glyoxal-phenolic resins and sisal fibers.

Lignocellulosic materials can significantly contribute to the development of biobased composites. In this work, glyoxal-phenolic resins for composites were prepared using glyoxal, which is a dialdehyde obtained from several natural resources. The resins were characterized by (1)H, (13)C, 2D, and (31)P NMR spectroscopies.