The application of deep eutectic solvents (DESs) to dissolve metal oxides in lithium‐ion batteries (LIBs) recycling represents a green technological alternative to the mineral acids employed in hydrometallurgical recycling processes. However, DESs are much more expensive than mineral acids and must be reused to ensure economic feasibility of LIB recycling. To evaluate DES reusability, the role of the choline chloride‐ethylene glycol DES decomposition products on metal oxides dissolution was investigated. The temperatures generally applied to carry on this DES leaching induced the formation of decomposition products that ultimately improved the ability to dissolve LIB metal oxides. The characterization of DES decomposition products revealed that the improved metal dissolution was mainly determined by the formation of Cl3−, which was proposed to play a pivotal role in the oxidative dissolution of LIB metal oxides.

The effect of the annealing few degrees above the glass transition temperature (T da = 62 C) on the physical aging (T pa = 51 C) of amorphous quenched poly(L-lactide) is investigated by an implementation of variable temperature Fourier transform infrared (FTIR). By using a temperature program composed of a linear heating ramp superimposed to a temperature modulation (modulated temperature FTIR), the reversing and nonreversing intensity variation of selected bands, related to high-energy gg and low-energy gt conformers, is investigated. It is observed that the annealing above T g changes irreversibly the conformation distribution of the liquid polymer. The glasses obtained from annealed and nonannealed liquids behave differently, evolving in the physical aging toward their own liquid state and retaining the memory of their original condition before the vitrification. The recovery through T g of the relaxation occurred in the physical aging depends not only from aging conditions but also by the thermal history of the sample above the T g .

Molecular self‐assembly has significant potential in the field of sensing. Polydiacetylenes (PDAs) are conjugated polymers possessing peculiar optical properties obtained by photopolymerization of self‐assembled diacetylene monomers. Herein, the blue‐to‐red phase transition upon either thermal stimulus or interaction with cyclodextrins (CDs) of two PDAs, bearing either carboxylic (PCDA) or amino (PCDA‐NH2) polar heads, is investigated to develop a colorimetric sensor for food phenolic antioxidants. The change in the PDA polar head does not affect significantly thermo‐chromatic transition. Upon thermal stimulus, in both PDAs, color transition occurs straightforward between two distinct stable states and does not involve the disordering of the PDA crystal phase, as revealed by UV–vis spectroscopy and SAXS analysis. Contrarily, PDA/α‐CD interaction is influenced by intermolecular forces among PDA polar heads and is more efficient for PCDA. α‐CDs presumably cause changes in both PDA backbone conformation and local environment surrounding the individual PDA chains. The PCDA/α‐CD assemblies are investigated as colorimetric sensors for the detection of Tyrosol (Ty) and caffeic acid (CAF), by using the principle of competitive inclusion complex formation. The system results to be more sensitive to CAF than Ty and may permit the determination of CAF in concentration ranges suitable for different food products.

Polylactides (PLAs) are a class of polymers that are very appealing in biomedical applications due to their degradability in nontoxic products, tunable structural, and mechanical properties. However, they have some drawbacks related to their high hydrophobicity, lack of functional groups able to graft bioactive molecules, and solubility in unsafe solvents. To circumvent these shortcomings, porous scaffolds for tissue engineering were prepared by vigorously mixing a solution of isotactic and atactic PLA in nontoxic ethyl acetate at 70 °C with a water solution of choline taurinate. The partial aminolysis of the polymer ester bonds by taurine -NH2 brought about the formation of PLA oligomers with surfactant activity that stabilized the water-in-oil emulsion. Upon drying, a negligible shrinking occurred, and mechanically stable porous scaffolds were obtained. By varying the polymer composition and choline taurinate concentration, it was possible to modulate the pore dimensions (30–50 µm) and mechanical properties (Young’s moduli: 1–6 MPa) of the samples. Furthermore, the grafted choline taurinate made the surface of the PLA films hydrophilic, as observed by contact angle measurements (advancing contact angle: 76°; receding contact angle: 40°–13°). The preparation method was very simple because it was based on a one-pot mild reaction that did not require an additional purification step, as all the employed chemicals were nontoxic.

Eugenol is a phenolic monoterpenoid, obtained mainly from clove oil and lignin, with a peculiar chemical structure endowed with an allyl group and a phenol group, which can be easily...

Modulated temperature techniques allow to separate the reversing and non‐reversing contributions of material transitions. To investigate reversible crystallization and melting of isotactic polypropylene (iPP) at microstructural level, in this research, modulated temperature Fourier transform infrared (MTFTIR) and quasi‐isothermal FTIR (QIFTIR) analyses are used. By following the intensity variation of iPP regularity bands, associated with 31 helix structures of different lengths (n repeating units), MTFTIR evidences that, independently from helix length, a reversing coil–helix transition takes place few degrees below the non‐reversing crystallization onset. By comparing spectroscopic and differential scanning calorimetry experiments performed in quasi‐isothermal conditions, the reversing transition was found to be associated with the reversible melting‐crystallization phenomenon. Moreover, QIFTIR evidences that helices of different lengths contribute differently to the reversible transition: the helices composed of n = 10 and n = 12 are active into all the explored temperature range (30–130 °C) whereas the shortest (n = 6) and the longest (n > 15) helices contribute to reversibility at T > 100 °C. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 922–931

Hyaluronic acid (HA) is a naturally occurring biopolymer that has been employed for a plethora of medicinal applications. Nevertheless, as HA is a natural polysaccharide, it can be a substrate able to promote microbial growth and proliferation. Biopolymer−drug conjugates have gained attention over the years to overcome drawbacks of each single component. Within this context, thymol (Thy), a phenolic compound occurring in essential oils (EOs) extracted from Thymus and Origanum, has been largely studied for its antimycotic applications. However, it is characterized by a low water solubility and moderate cytotoxicity. Herein, we report an innovative HA−thymol conjugate (HA-Thy) biomaterial to circumvent the drawbacks of free thymol use by providing the polymer conjugate with the beneficial properties of both components. Preliminary biological tests evidenced the decrease of thymol cytotoxicity for the HA-Thy conjugate, paired with a promising antibiofilm formation activity against Candida albicans, similar to pure thymol, highlighting its potential application as a preservative biomaterial in formulations.

In this paper, the application of a temperature modulation to the temperature-resolved FTIR analysis is reported. The advantage offered by the spectroscopic investigation, able to follow the micro-structural and conformational sample modification involved in sample thermal transformation, was merged to that of temperature modulation, related to the possibility to separate the reversing (in-equilibrium within the experimental condition) to the non-reversing (non-equilibrium) processes. The potentiality of the technique (modulated temperature FTIR, MTFTIR) is highlighted through the study of the thermal transitions of amorphous poly(ethylene terephthalate) from 50 °C to the cold-crystallization. After the presentation of the theoretical framework and the experimental conditions, a step-by-step description of acquired data elaboration is given. The total variation of a selected band intensity as function of mean temperature as well as its reversing and non-reversing components are obtained. The evolution of the bands at 1340 and 971 cm−1, assigned to the trans conformation of the ethylenic unit and to the all-trans conformation of the repeating unit, respectively, are investigated. As expected, the glass transition is observed in the reversing components meanwhile the recovery of the glass relaxation and cold crystallization in non-reversing ones. Particularly interesting resulted the behaviour of the sample in the supercooled liquid state, between the glass transition and the cold-crystallization onset, in which the results show that the ethylenic conformers are in-equilibrium while the all-trans sequences are not. MTFTIR is confirmed to be a technique particularly suitable for the characterization of non-equilibrium conformational states of polymers.