On the physico-chemical basis of self-nanosegregation giving magnetically-induced birefringence in dibutyl phosphate/bis(2-ethylhexyl) amine systems

Biomaterials and Their Potentialities as Additives in Bitumen Technology: A Review

The carbon footprint reduction mandate and other eco-friendly policies currently in place are constantly driving the trend of the synthesis and application of sustainable functional materials. The bitumen industry is not an exception to this trend and, every day, new technologies that facilitate safer, cost effective and more sustainable industrial processes and road paving operations are being researched and brought to light. A lot of research is currently ongoing to improve bitumen's properties due to its use as a binder in road paving processes. Over the years, the most common method to improve bitumen's properties has been with the use of additives. The major drawback in the use of these additives is the fact that they are substances of strong chemical nature which are either too acidic, too basic or emit toxic fumes and volatile organic compounds into the environment. In the long run, these chemicals are also toxic to the road pavement personnel that carry out the day to day industrial and paving operations. This led researchers to the initiative of synthesizing and applying biomaterials to be used as additives for bitumen. In this light, several studies have investigated the use of substances such as bio-oils, natural waxes, gum, polysaccharides and natural rubber. This literature review is aimed at classifying the different bio-based materials used to improve bitumen's properties and to provide a deeper knowledge of the application of these biomaterials in bitumen technology. In general, we highlight how the research efforts elaborated herein could potentially foster safer, sustainable, eco-friendly approaches to improving bitumen's properties while also promoting a circular economy.

When Physical Chemistry Meets Circular Economy to Solve Environmental Issues: How the ReScA Project Aims at Using Waste Pyrolysis Products to Improve and Rejuvenate Bitumens

Urban waste management is a hard task: more than 30% of the world’s total production of Municipal Solid Wastes (MSW) is not adequately handled, with landfilling remaining as a common practice. Another source of wastes is the road pavement industry: with a service life of about 10–15 years, asphalts become stiff, susceptible to cracks, and therefore no longer adapted for road paving, so they become wastes. To simultaneously solve these problems, a circular economy-based approach is proposed by the ReScA project, suggesting the use of pyrolysis to treat MSW (or its fractions as Refuse Derived Fuels, RDFs), whose residues (oil and char) can be used as added-value ingredients for the asphalt cycle. Char can be used to prepare better performing and durable asphalts, and oil can be used to regenerate exhaust asphalts, avoiding their landfilling. The proposed approach provides a different and more useful pathway in the end-of-waste (EoW) cycle of urban wastes. This proof of concept is suggested by the following two observations: (i) char is made up by carbonaceous particles highly compatible with the organic nature of bitumens, so its addition can reinforce the overall bitumen structure, increasing its mechanical properties and slowing down the molecular kinetics of its aging process; (ii) oil is rich in hydrocarbons, so it can enrich the poor fraction of the maltene phase in exhaust asphalts. These hypotheses have been proved by testing the residues derived from the pyrolysis of RDFs for the improvement of mechanical characteristics of a representative bitumen sample and its regeneration after aging. The proposed approach is suggested by the physico-chemical study of the materials involved, and aims to show how the chemical knowledge of complex systems, like bituminous materials, can help in solving environmental issues. We hope that this approach will be considered as a model method for the future.

On the nanoscopic structural heterogeneity of liquid n-alkyl carboxylic acids

Herein we report the first in-depth structural characterisation of simple linear carboxylic acids with alkyl tail length ranging from one to six carbon atoms. By means of the SWAXS technique, a pronounced nanoscopic heterogeneity evolving along the aliphatic portion of the molecule is highlighted. Via classical molecular dynamics, the origin of such heterogeneity is unambiguously assigned to the existence of aliphatic domains resulting from the self-segregation of the polar and apolar portions of the molecules. Furthermore, the structural correlation of aliphatic-separated polar domains is responsible for observing the so-called "pre-peak" in the SAXS region.

Synthesis, Characterization and Mechanical Properties of Novel Bio-Based Polyurethane Foams Using Cellulose-Derived Polyol for Chain Extension and Cellulose Citrate as a Thickener Additive

A novel series of bio-based polyurethane composite foams was prepared, employing a cellulose-derived polyol for chain extension and cellulose-citrate as a thickener additive. The utilized polyol was obtained from the reduction reaction of cellulose-derived bio-oil through the use of sodium borohydride and iodine. Primarily, we produced both rigid and flexible polyurethane foams through chain extension of the prepolymers. Secondly, we investigated the role of cellulose citrate as a polyurethane additive to improve the mechanical properties of the realized composite materials. The products were characterized by FT-IR spectroscopy and their morphologies were analysed by SEM. Mechanical tests were evaluated to open new perspectives towards different applications.

Differential Scanning Calorimetry as a New Method to Evaluate the Effectiveness of Rejuvenating Agents in Bitumens

To date, few methods allow distinguishing a fluxing effect of an additive for bitumen from a regenerating effect. This research aims at identifying a method to accurately establish whether an oxidized bitumen has been regenerated or has simply been fluxed by a softener. Oxidized bitumens, simulating the aging process that results in road pavement lifetime, were prepared by the Rolling thin film oven test (RTFOT) procedure for 225 min and the Pressure Aging Vessel (PAV) procedure. Their asphaltene parts were extracted and analyzed by calorimetry (Differential Scanning Calorimetry DSC), and the results were compared with the presence and absence of a fluxing agent and real rejuvenators. The self-consistent results showed that the thermal properties of the asphaltene fractions is a sound probe to monitor the effect of rejuvenation clearly distinguishable from the mere fluxing effect. This preliminary study might allow the creation of standard protocols capable of identifying a priori the rejuvenating effect of an additive in the future. Furthermore, given the widespread use of calorimetry for the characterization, it tends to become a widely accessible and useful tool for this purpose in material characterization laboratories.

Enhanced Li+ Transport in Ionic Liquid-Based Electrolytes Aided by Fluorinated Ethers for Highly Efficient Lithium Metal Batteries with Improved Rate Capability

FSI^- -based ionic liquids (ILs) are promising electrolyte candidates for long-life and safe lithium metal batteries (LMBs). However, their practical application is hindered by sluggish Li⁺ transport at room temperature. Herein, it is shown that additions of bis(2,2,2-trifluoroethyl) ether (BTFE) to LiFSI-Pyr₁₄ FSI ILs can effectively mitigate this shortcoming, while maintaining ILs' high compatibility with lithium metal. Raman spectroscopy and small-angle X-ray scattering indicate that the promoted Li⁺ transport in the optimized electrolyte, [LiFSI]₃ [Pyr₁₄ FSI]₄ [BTFE]₄ (Li₃ Py₄ BT₄ ), originates from the reduced solution viscosity and increased formation of Li⁺ -FSI^- complexes, which are associated with the low viscosity and non-coordinating character of BTFE. As a result, Li/LiFePO₄ (LFP) cells using Li₃ Py₄ BT₄ electrolyte reach 150 mAh g^-1 at 1 C rate (1 mA cm^-2 ) and a capacity retention of 94.6% after 400 cycles, revealing better characteristics with respect to the cells employing the LiFSI-Pyr₁₄ FSI (operate only a few cycles) and commercial carbonate (80% retention after only 218 cycles) electrolytes. A wide operating temperature (from -10 to 40 °C) of the Li/Li₃ Py₄ BT₄ /LFP cells and a good compatibility of Li₃ Py₄ BT₄ with LiNi_0.5 Mn_0.3 Co_0.2 O₂ (NMC532) are demonstrated also. The insight into the enhanced Li⁺ transport and solid electrolyte interphase characteristics suggests valuable information to develop IL-based electrolytes for LMBs.

A Presentation of Ionic Liquids as Lubricants: Some Critical Comments

Ionic liquids (ILs) are liquid materials at room temperature with an ionic intrinsic nature. The electrostatic interactions therefore play a pivotal role in dictating their inner structure, which is then expected to be far from the traditional pattern of classical simple liquids. Therefore, the strength of such interactions and their long-range effects are responsible for the ionic liquid high viscosity, a fact that itself suggests their possible use as lubricants. More interestingly, the possibility to establish a wide scenario of possible interactions with solid surfaces constitutes a specific added value in this use. In this framework, the ionic liquid complex molecular structure and the huge variety of possible interactions cause a complex aggregation pattern which can depend on the presence of the solid surface itself. Although there is plenty of literature focusing on the lubricant properties of ionic liquids and their applications, the aim of this contribution is, instead, to furnish to the reader a panoramic view of this exciting problematic, commenting on interesting and speculative aspects which are sometimes neglected in standard works and trying to furnish an enriched vision of the topic. The present work constitutes an easy-to-read critical point of view which tries to interact with the imagination of readers, hopefully leading to the discovery of novel aspects and interconnections and ultimately stimulating new ideas and research.

Structural Characterization of Biomaterials by Means of Small Angle X-rays and Neutron Scattering (SAXS and SANS), and Light Scattering Experiments

Scattering techniques represent non-invasive experimental approaches and powerful tools for the investigation of structure and conformation of biomaterial systems in a wide range of distances, ranging from the nanometric to micrometric scale. More specifically, small-angle X-rays and neutron scattering and light scattering techniques represent well-established experimental techniques for the investigation of the structural properties of biomaterials and, through the use of suitable models, they allow to study and mimic various biological systems under physiologically relevant conditions. They provide the ensemble averaged (and then statistically relevant) information under in situ and operando conditions, and represent useful tools complementary to the various traditional imaging techniques that, on the contrary, reveal more local structural information. Together with the classical structure characterization approaches, we introduce the basic concepts that make it possible to examine inter-particles interactions, and to study the growth processes and conformational changes in nanostructures, which have become increasingly relevant for an accurate understanding and prediction of various mechanisms in the fields of biotechnology and nanotechnology. The upgrade of the various scattering techniques, such as the contrast variation or time resolved experiments, offers unique opportunities to study the nano- and mesoscopic structure and their evolution with time in a way not accessible by other techniques. For this reason, highly performant instruments are installed at most of the facility research centers worldwide. These new insights allow to largely ameliorate the control of (chemico-physical and biologic) processes of complex (bio-)materials at the molecular length scales, and open a full potential for the development and engineering of a variety of nano-scale biomaterials for advanced applications.

Sulfonated Cellulose-Based Magnetic Composite as Useful Media for Water Remediation from Amine Pollutants

Commercially available microcrystalline cellulose (MCC) was functionalized using chlorosulfonic acid, while iron oxide nanoparticles (IONPs) were adsorbed on the surface of the cellulose derivative by the Massart’s co-precipitation method. The obtained magnetite-decorated sulfate cellulose nanoparticles (MDSCNs) were characterized via Fourier transform infrared (FTIR) spectroscopy, scanning-electron microscopy (SEM), and elemental analysis, while the acidity of the functionalized cellulose was determined using an acid–base titration with phenolphthalein as an indicator. Furthermore, in order to determine the adsorptive power of the obtained composite, a series of analyses were performed on aqueous amine pollutants using flame ionization detection gas chromatography (GC-FID). The results of this study clearly show how a bio-compatible green polymer as cellulose can be easy functionalized in order to improve its chemical and physical properties, obtaining a magnetic composite useful in water purification. Adsorption percentages up to 90% and a very small amount of composite used (100 mg) proved how our material can be a powerful tool in environmental remediation.