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La mayoría de los materiales poliméricos usados diariamente se obtienen a partir de fuentes fósiles. Debido a los recursos limitados de petróleo y a los problemas generados por la contaminación de los plásticos, es necesario encontrar nuevas fuentes renovables para la obtención de materiales de uso cotidiano. Los bioplásticos obtenidos a partir de la biomasa constituyen la principal alternativa a los materiales poliméricos tradicionales obtenidos del petróleo. Dentro de la biomasa, el limoneno se revela como una plataforma química prometedora. Así pues, durante la última década el uso de limoneno se ha investigado con intensidad y actualmente se han evidenciado nuevos procesos catalíticos capaces de proporcionar excelentes productos químicos y polímeros a partir de él. En este artículo se analizarán las diferentes aplicaciones del limoneno en la industria de polímeros como precursor orgánico para la síntesis o el procesado de bioplásticos avanzados y multifuncionales.

Taking advance of the fiber-reinforced polymer process, commonly used in the fabrication of polymer composites, in this work we used electrospun microfibers to reinforce self-healing ionomeric polymers producing sandwich-type composites. In particular, three-layer stack with poly(lactic acid), PLA, electrospun fibers in between two layers of commercial smart polymers has been obtained based on poly(ethylene-co-methacrylic acid) (EMAA) copolymers, well-know with the tradename of Nucrel® and Surlyn®, both of them manufactured by Dupont™ Company. Surlyn® is the corresponding ionomer of Nucrel® in which the MAA groups are partially neutralized with sodium ions. In general, one of the main problems of thermoplastic composites, that provoke a lower impregnation of the fiber, is the high viscosity of the molten matrix. Therefore, in this work, we used electrospun microfibers in order to solve impregnation problem, thus considering that electrospinning process is an accessible, versatile and low-cost technique for fibers formation in the range of micron and nanometers. In order to create the sandwich-type structure, firstly, the optimization of the processing window has achieved in order to maintain the randomly oriented fiber structure on the final composites. In particular, the creation of sandwich-type structure with Surlyn® reinforced with woven non-woven electrospun fibers based on PLA with enhanced mechanical as well as hardness and wear resistance can be used for future active packaging solutions., España. Ministerio de Economía, Industria y Competitividad; ADITIMAT-CM project, from Comunidad de Madrid

In this work the thermally-activated shape memory response of biodegradable nanocomposites based on PLA/PCL blend reinforced with different type of cellulose nanocrystals has been reported, and compared with those of the neat matrix, at the same transition temperature of 55 °C and at the same different deformations, 50%, 100% and 150%. In particular, cellulose nanocrystals have been synthesized and then functionalized by "grafting from" reaction by ring opening polymerization of both PLLA and PCL using the &-OH groups onto the cellulose nanocrystals surface as initiators for the reaction. The morphology, thermal and mechanical analysis have been performed in order to obtain the parameters for the thermo-mechanical shape memory cycles. Moreover, the addition of the CNC-based nanofillers on the compatibility of PLA-PCL blends in 70:30 proportion has been evaluated. All the biodegradable nanocomposite formulations showed excellent shape memory response, similar to those of the neat matrix, with strain recovery ratio and strain fixity ratio higher than 80% and 90%, respectively. This fact indicates that in this case, the shape memory response of the nanocomposites is mainly controlled by the response of the neat blend and they are slightly influenced by the increase of compatibility between the components of the blend. In addition, all nanocomposite films were fully disintegrated under composting conditions confirming their biodegradable nature, obtaining that the presence of CNC-based nanofillers speeds up the disintegration rate of the nanocomposites in comparison with the pure matrix.

Two non-toxic potassium compounds, 1 and 2, with a commercial oximate ligand have been prepared and fully spectroscopically characterized. Their activity as catalysts for the ring-opening polymerization (ROP) process of LLA has been studied, showing that they are extremely active and able to polymerize the monomer in a few minutes. For derivative 2, the presence of a crown ether in the potassium coordination sphere affects the nuclearity of the compound and consequently its solubility, with both aspects having an influence in the polymerization process. Detailed studies of the polymerization mechanism have been performed, and an unusual anionic mechanism was observed in absence of a co-initiator. Indeed, the monomer deprotonation generates a lactide enolate, which initiates the polymerization propagation. On the contrary, when a 1:1 ratio of cat:BnOH is used, a mixture of mechanisms is observed, the anionic mechanism and the activated monomer one, while from a cat:BnOH ratio of 1:2 and over, only the activated monomer mechanism is observed.