Synthesis of new defoamer agents and characterization of cementitious formulations.

The production of cementitious formulations involves the addition of chemical additives essential for the optimization of many properties. Superplasticizers are considered additives of great interest but when mixed with concrete they lead to an undesirable increase of air content, with the consequent development of foam. This can adversely affect both mechanical properties and workability, therefore, the use of an antifoam agent is also necessary which should be able to prevent or destroy the foam. This work aims to synthesize esters derived from the reaction of glycine betaine with saturated and unsaturated fatty alcohols of different chain lengths. The reaction products were analyzed by 1H NMR analysis, and the stability of antifoam agents in a superplasticizer solution was studied through foaming tests according to the Ross-Miles method. At the same time, their effectiveness in the cementitious systems was evaluated through flow Table tests. Finally, the effectiveness of the antifoam agents was quantified through an image analysis software, Image J, which allowed the investigation of the contents of the bubble in concrete samples. All synthesized antifoams showed properties superior to the commercial product, especially defoamers containing saturated fatty alcohols. It has been found that alcohols with too small or too long carbon chains were not effective. In particular, it was verified the optimal range of carbon atoms number contained in the antifoam chain which included between 12 and 14.

Tailoring Synthetic Pelargonic Acid Esters for Bio-Based Lubricant Applications: Exploring the Relationship between Structure and Properties.

Pelargonic acid (PA) is commercially obtained by oxidative cleavage of fatty acid double bonds. Its esters are interesting compounds used to create bio-based products. An industrially relevant application of these compounds is in the field of solvent manufacturing and formulation of green lubricating oils. The physical-chemical and rheological properties of these esters are influenced by the structural features of the alcohol used as starting materials, such as chain length, number of unsaturation, and degree of branching. This work provides an in-depth study of the existing structure-properties relations for fatty acid alkyl esters obtained from PA and different alcohols [i.e., 2-ethylhexanol (EtHex), ethylene glycol, 1,3-propanediol, 1,4-butanediol, trimethylolpropane, and pentaerythritol]. The aim is to evaluate the use of the synthesized product for the formulation of bio-based lubricants. The chosen alcohols are frequently employed in the preparation of bio-based lubricants. In addition, most of them, such as EtHex and diols, can be derived from biomass sources, contributing to the sustainability of the obtained products. For comparison purposes, some of these alcohols were also used for the synthesis of the corresponding oleic acid esters, which were chosen as a benchmark due to their common use in the synthesis of bio-based lubricants. The influence of the structural factors on the viscosity, pour point (PP), and oxidation stability of the synthesized esters was highlighted by comparing the obtained results. Pelargonates showed lower viscosities and higher PPs than that of the oleates, but they present high stabilities to the oxidation due to the absence of unsaturation.

Understanding Marine Biodegradation of Bio-Based Oligoesters and Plasticizers.

The study reports the enzymatic synthesis of bio-based oligoesters and chemo-enzymatic processes for obtaining epoxidized bioplasticizers and biolubricants starting from cardoon seed oil. All of the molecules had MW below 1000 g mol-1 and were analyzed in terms of marine biodegradation. The data shed light on the effects of the chemical structure, chemical bond lability, thermal behavior, and water solubility on biodegradation. Moreover, the analysis of the biodegradation of the building blocks that constituted the different bio-based products allowed us to distinguish between different chemical and physicochemical factors. These hints are of major importance for the rational eco-design of new benign bio-based products. Overall, the high lability of ester bonds was confirmed, along with the negligible effect of the presence of epoxy rings on triglyceride structures. The biodegradation data clearly indicated that the monomers/building blocks undergo a much slower process of abiotic or biotic transformations, potentially leading to accumulation. Therefore, the simple analysis of the erosion, hydrolysis, or visual/chemical disappearance of the chemical products or plastic is not sufficient, but ecotoxicity studies on the effects of such small molecules are of major importance. The use of natural feedstocks, such as vegetable seed oils and their derivatives, allows the minimization of these risks, because microorganisms have evolved enzymes and metabolic pathways for processing such natural molecules.

Branched alkyldimethylamine oxide surfactants: An effective strategy for the design of high concentration/low viscosity surfactant formulations.

HYPOTHESIS: The rational design of branched-tail surfactants is a suitable strategy to obtain low-viscosity surfactant-rich isotropic aqueous mixtures with negligible effects on biodegradability. This opens a way to the design of concentrated ("water-free") surfactant formulations, highly attractive for their ecological and economic benefits. EXPERIMENTS: The aggregation behaviour of N,N-dimethyl-2-propylheptan-1-amine oxide (C10DAO-branched) in aqueous mixtures is investigated across the entire composition range by polarized optical microscopy, small angle X-ray and neutron scattering, electron paramagnetic resonance, and pulse-gradient stimulated echo nuclear magnetic resonance. The humidity scanning quartz crystal microbalance with dissipation monitoring technique is validated as a tool for the fast screening of surfactants phase behaviour. Furthermore, the shear viscosities and viscoelastic moduli of the systems are determined by rheological measurements. FINDINGS: With respect to the linear isomer, C10DAO-branched presents a much lower tendency to form lyotropic liquid crystalline phases. Except for a narrow composition and temperature range in which a lamellar structure is observed, C10DAO-branched aqueous mixtures are isotropic liquids whose microstructure changes, with increasing concentration, from micellar solutions to unstructured dispersions of hydrated surfactant molecules. Low-viscosity was found for all these mixtures, including the most concentrated ones. Thus, the introduction of a single short side-chain in the tail is demonstrated to be an effective approach to increase the active concentration in surfactant formulations.

Confocal microscopy and imaging profilometry: A new tool aimed to evaluate aesthetic procedures.

According to the American Academy of Aesthetic Plastic Surgeons, more than 11 million cosmetic surgical and nonsurgical procedures were performed by board-certified plastic surgeons, dermatologists and otolaryngologists in the United States, totaling more than 12 billion dollars. We performed a retrospective observational multi-centric study on patients treated with a non-animal origin cross-linked hyaluronic acid with different molecular weights for nasolabial folds, evaluating through a new imaging system, profilometric techniques with the confocal microscopy, the durability, the efficacy and the safety of this product. From 25 patients, 150 silicone casts were obtained: 75 casts of the right nasolabial fold and 75 casts of the left nasolabial fold. Roughness arithmetical average of the right fold at T2 decreased by 50% versus T0 and by 40% compared to T1; at T2, it decreased by the 45% versus T0 and by 35% compared to T1. No side effects were reported. Results proved that the analysis of the skin microreliefs through confocal microscopy is a new imaging system that allows to evaluate with precision and safety the results of aesthetic treatments such as fillers objectively.

Synthesis of Monoalkyl Glyceryl Ethers by Ring Opening of Glycidol with Alcohols in the Presence of Lewis Acids.

The present work deals with the production of monoalkyl glyceryl ethers (MAGEs) through a new reaction pathway based on the reaction of glycidol and alcohols catalyzed by Lewis acid-based catalysts. Glycidol is quantitatively converted with high selectivity (99 %) into MAGEs under very mild reaction conditions (80 °C and 0.01 mol % catalyst loading) in only 1 h using Al(OTf)3 or Bi(OTf)3 as catalyst. The proposed method enhances the choice of possible green synthetic approaches for the production of value-added products such as MAGEs.