Manuel Carmona

The polyurethane industry urgently requires efficient recycling strategies to support a sustainable circular economy. Split‑phase glycolysis enables the recovery of polyols, but managing the bottom‑phase carbamates remains challenging, as their decomposition can generate toxic toluenediamine (TDA). Here, we successfully synthesize five conductive polyazomethines (PAM‑1 to PAM‑5) through solution polycondensation, reacting TDA recovered from glycolysis waste with various dialdehydes, thereby demonstrating that this upcycled precursor can be transformed into functional materials with tunable properties. Structural, thermal, morphological, and optoelectronic analyses show that the chemical nature of the dialdehyde monomer strongly dictates the final polymer characteristics. GPC results reveal relatively short chain lengths with low polydispersity, consistent with terminal aldehyde groups detected by NMR. FTIR and NMR confirm the formation of azomethine linkages and the incorporation of TDA‑derived units into all polymer backbones. Thermal analysis indicates high stability prior to degradation and glass transition temperatures between 171 and 229 °C. Optoelectronic characterization shows semiconductor‑like optical band gaps (2.59–3.09 eV) and favorable HOMO/LUMO levels supported by DFT simulations, indicating suitability for photodetectors, sensors, organic transistors, and photovoltaic devices. Overall, this work highlights the potential of polyazomethines derived from upcycled waste for next‑generation optoelectronic technologies.

Oleic-based trimethylolpropane (TMP) ester mixtures can be produced via esterification reaction between oleic acid (OA) and TMP, presenting important application as biobased lubricants. In this study, a new mathematical model that allows us to predict kinematic viscosities of such mixtures based on kinematic viscosity sensitivity parameters from product functional groups was developed, and it was also checked by fitting the experimental kinematic viscosities of the biolubricant products at 40 and 100 °C. This way, it is possible to predict kinematic viscosities and the viscosity index of these biolubricant mixtures and even pure TMP-esters without the availability to measure purified compounds. Moreover, the influence on the viscosity properties of the different chemical functional groups can be assessed with this physical model. So, the deleterious or beneficial effects of intermediate products and unreacted OA on the biolubricant viscosity index (VI) were quantified, showing that Trioletate and also Dioleate TMP-ester and their mixtures meet very interesting lubricant properties (VI up to 218), whereas the Monooleate TMP-ester and the unreacted OA decrease dramatically the viscosity properties. We believe that these findings can pave the way for the improvement and development of bio-based lubricant formulations towards effective industrial development.

The scale-up and the economic feasibility of the synthesis of St-MMA-GMA-PEGMA particles biofunctionalized with HSA were studied. First, the geometrical similarity of laboratory and pilot plant reactors was checked to develop the scale up of the process according to a criterion of partial similarity. The selected criterion was constant Re number. Then, a reaction in the pilot plant scale was carried out, confirming the suitability of the scale-up criterion, since particles with similar characteristics (same particle size with a deviation of just 6%) and functional groups were obtained. Finally, the design of an industrial plant able to produce 581 Tm/year of HSA functionalized St-MMA-GMA-PEGMA particles was addressed. The economic feasibility of this plant was confirmed by a value of internal rate of return (IRR) of 14.8% and a net present value (NPV) of 5452 M€, with a payback time between six and seven years, for the price of a cartridge 25% lower than that from the current treatments for bilirubin removal from patients with liver failure.

This work describes the development of styrene-divinylbenzene (St-DVB) particles with polyethylene glycol methacrylate (PEGMA) and/or glycidyl methacrylate (GMA) brushes for the removal of bilirubin from blood in haemodialyzed patients. Bovine serum albumin (BSA) was immobilized onto the particles using ethyl lactate as a biocompatible solvent, which allowed the immobilization of up to 2 mg BSA/g of particles. The presence of albumin on the particles increased their capacity for bilirubin removal from phosphate-buffered saline (PBS) by 43% compared to particles without albumin. The particles were tested in plasma, finding that St-DVB-GMA-PEGMA particles that had been wetted in ethyl lactate with BSA reduced the concentration of bilirubin in plasma by 53% in less than 30 min. This effect was not observed in particles without BSA. Therefore, the presence of albumin on the particles enabled quick and selective removal of bilirubin from plasma. Overall, the study highlights the potential use of St-DVB particles with PEGMA and/or GMA brushes for bilirubin removal in haemodialyzed patients. The immobilization of albumin onto the particles using ethyl lactate increased their capacity for bilirubin removal and enabled quick and selective removal from plasma.

Hyperbilirubinemia is one of the main causes of death in patients with severe hepatic problems, which justifies the research for bilirubin removal solutions. In this study, St-MMA particles with PEGMA and/or GMA brushes were synthesized. First, the recipe for St-MMA was optimized and then adapted for PEGMA and GMA incorporation. Different solvents were then assayed to improve the BSA immobilization capacity of the particles. Ethyl lactate proved to be the best solvent, reaching a BSA immobilization capacity improvement of up to 60% for St-MMA-GMA-PEGMA particles. These particles also presented the best results for BR removal from PBS. No significant differences in the final capacity for BR removal from PBS media were observed when BSA was attached to the particles; however, the kinetics were greatly improved, requiring half the time. Finally, St-MMA-GMA-PEGMA particles that were wetted in EL with BSA reduced the bilirubin concentration in plasma from levels that threaten the survival of critical patients to levels close to those of healthy individuals in less than 30 min. On the contrary, particles without BSA were unable to remove bilirubin from plasma. Thus, the attachment of albumin to the particles plays a key role in selectively reducing bilirubin levels.

Thermoregulating composites were produced by using a thermoregulating slurry (NPCS) containing nanoencapsulated phase change material (NPCM) from poly(styrene-co-divinylbenzene) as shell and the commercial paraffin Rubitherm®RT27 as core material. These composites were synthesized by using the constitutive water of the slurry as setting water and changing the NPCM/Hemihydrate (NPCM/Hem) mass ratio within 0.0–0.41. It was found that nanoparticles were uniformly dispersed into the gypsum, and the gypsum crystal morphology was tuned by the addition of the slurry. Attending to the thermal properties, these materials can work either as insulating or thermal energy storage materials, decreasing the thermal conductivity up to ~ 50%, whereas the thermal energy storage (TES) capacity is enlarged in a ~ 140%, respect to the pure gypsum, when the maximum NPCM/Hem mass ratio was used. This composite had a latent heat of 30.2 J g⁻¹ and a heat capacity of equivalent 3.5 J g⁻¹ K⁻¹. Composites from a NPCM/Hem mass ratio up to 0.15 satisfied European mechanical standard EN 13,279–1 for gypsum binders and gypsum plasters and all of them, presented a bulk density higher than 0.60 g cm⁻³. The addition of a 41% in mass of nanocapsules allowed to save 13.5 kWh m⁻³ and, reducing the CO₂ emissions up to 3.4 kg of CO₂ per operating cycle. The use of this new material would lead to significant energy and economic savings, as well as a considerable reduction in the emission of polluting gases into the atmosphere.

The production of oleic‐based trimethylolpropane (TMP) esters via the esterification reaction between oleic acid (OA) and TMP in a reactive distillation system, employing the environmentally friendly catalyst methanesulfonic acid, was explored. The homogeneous acid catalyst, the OA/TMP molar ratio within 1.0–3.0, the esterification reaction enhancement and a new purification technique, using choline hydroxide (ChOH), for obtaining choline carboxylate as a subproduct, were studied. It was found that using an OA/TMP molar ratio of 3.0, only unreacted OA remained as an impurity. The deleterious or beneficial effect of intermediate products, unreacted OA and temperature on the kinematic viscosity were unraveled. The kinematic viscosity behavior for the products was practically independent of temperature but an abrupt enlargement of the kinematic viscosity was observed in the presence of functional groups in the intermediate esters, even greater than the Mark–Houwink counterpart effect. On contrary, the presence of OA in the final product decreased the kinematic viscosity attending to its lower molecular weight with respect to the trimethylolpropane trioleate one. It was found that trimethylolpropane monooleate is undesirable for the viscosity index, whereas the presence of trimethylolpropane dioleate could also increase the viscosity index to a small extent, requiring a complex purification process. Finally, it is possible to affirm that the optimal TMP‐based lubricant obtained using an OA/TMP molar ratio of 3.0, after OA neutralization presented good marginal benefit and a viscosity index of 208.7, which is applicable for gear lubricants. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

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The synthesis of rigid polyurethane (RPU) foams containing thermoregulatory microcapsules has been carried out under reduced pressure conditions with a new foaming formulation to reduce the final composite densities. These optimized RPU foams were able to overpass the drawbacks exhibited by the previous composites over the studied temperature range, working as insulating and thermal energy storage materials. The change in the formulation allowed to decrease the final foam density and enhance their mechanical strength. The effect of the operating pressure (atmospheric, 800 mbar, and 700 mbar) and microcapsules content (up to 30 wt%) on the physical, mechanical, and thermal PU foam properties was studied. The reduction of the pressure from atmospheric to 800 mbar did not have any effect on the cell size, strut thickness, and compression strength 10% of deformation, the Young modulus being even higher at 800 mbar. Nevertheless, a strong impact on the microstructure and mechanical properties was observed for the foam composites obtained at 700 mbar. A deleterious impact on the RPU foams thermal conductivity was observed when using low-pressure conditions. Thermal analyses showed that a composite able to work as heat accumulator and thermal insulation both at transient and at steady state was achieved.

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin^®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).