Synthesis and characterisation of innovative polyesteramides using organocatalysis

[EN]Poly(e-caprolactam) and poly(L-lactide) are well known polymers that belong to polyamide and polyester families respectively. The aim of this project was to synthesise new poly(esteramide)s, poly(e-caprolactam-co-lactide) copolymers, using two different organocatalysts for the purpose of combining the good properties of each specie. Afterwards, the obtained copolymers were characterised by 1H and 13C NMR, ATR-FTIR, SEC, DSC and TGA. It was determined that in presence of the Brønsted acidic ionic liquids (BAILs) catalyst the L-lactide polymerisation was favoured, however the opposite was observed when the used catalyst was the strong Brønsted/Lewis base. The microstructures of the obtained copolymers had the dependence of the monomer composition and also of the selected catalyst. Thus, when the BAIL catalyst is used with high amounts of L-lactide, the character of the copolymer tends to be blocky, the same occurs when the catalyst is P4-t-Bu and the high composition corresponds to e-caprolactam. In the other cases, the microstructure of the copolymers could be considered as random.[EU]Poli(-kaprolaktama) eta poli(L-laktida), poliamida lehenengoa eta poliesterra bigarrena, aski ezagunak diren polimeroak dira. Lan honen helburua bi polimero hauen propietateak biltzen dituen kopolimeroa sortzea da, poli(esteramida)k, poli(-kaprolaktama-L-laktida) kopolimeroak, horretarako bi organokatalizatzaile desberdin erabiliz. Behin kopolimeroak sintetizatu direnean beraien karakterizazioa egin da teknika ezberdinak erabiliz: 1H eta 13C EMN, ATR-FTIR, SEC, DSC and TGA. Aztertu da Brønsted azido likido ioniko (BAIL) katalizatzailea erabiliz L-laktidaren polimerizazioa -kaprolaktamarena baino eraginkorragoa dela. Brønsted/Lewis base sendoa erabiltzean berriz, -kaprolaktamaren polimerizazioa gailentzen da. Sintetizatutako kopolimeroen mikroegiturek, kopolimeroaren konposizio eta katalizatzailearekiko menpekotasuna erakusten dute. Horrela, BAIL katalizatzailea erabiltzen denean L-laktidaren konposizio altuetan, lortutako kopolimeroak blokezko itxura izango du, berdina gertatuz P4-t-Bu katalizatzailea eta -kaprolaktamaren kantitate handietan. Gainerako konposizioetan aldiz, kopolimeroek zorizko mikroegiturak izateko joera azaltzen dute

Organocatalyzed closed-loop chemical recycling of thermo-compressed films of poly(ethylene furanoate)

[EN] Monomers obtained from renewable feedstocks have emerged as a sustainable alternative to petroleum derived polymers. One of the biomass derived polyesters that has recently been gaining attention as an alternative to petrochemical polyethylene terephtalate (PET) for food and beverage packaging applications is poly(ethylene furanoate) (PEF). However, similar to PET, PEF is not biodegradable or compostable and its end-of-life options must be thus considered to avoid contributing to the accumulation of plastic waste. In this manuscript, PEF films were first produced using thermo-compression, an industrially relevant processing method, and their thermal, mechanical, and barrier properties were determined and compared to those of PET and other biopolyesters to ascertain their suitability for food packaging. Thereafter, the chemical glycolysis of PEF film waste was investigated using a sustainable and thermally stable acid-base organocatalyst. After succesfully deconstructing PEF into bis(2-hydroxyethyl)-furan-2,5-dicarboxylate (BHEF), the obtained BHEF diester was used to resynthesize PEF using the same catalyst to generate a new biopolyester with similar thermal properties to the virgin one in a closed-loop cycle.The authors thank for technical and human support provided by IZO-SGI SGIker of UPV/EHU and European funding (ERDF and ESF). Authors gratefully acknowledge financial support from Spanish Ministry of Science and Innovation (MICI) through projects MAT2017-83373-R and RTI 2018-097249-B-C21. S. T.-G. acknowledges MICI for the funding received during his previous Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) and his current Ramon y Cajal contract (RYC2019-027784-I). A. M. I. acknowledges Prof. Cor Koning for the SSP reactor donated to POL group of Barcelona. Authors also thank India Glycols Ltd for kindly supplying bio-EG.Gabirondo, E.; Meléndez-Rodríguez, B.; Arnal, C.; Lagaron, JM.; Martínez De Ilarduya, A.; Sardon, H.; Torres-Giner, S. (2021). Organocatalyzed closed-loop chemical recycling of thermo-compressed films of poly(ethylene furanoate). Polymer Chemistry. 12(10):1571-1580. https://doi.org/10.1039/d0py01623cS15711580121

Polyether Single and Double Crystalline Blends and the Effect of Lithium Salt on Their Crystallinity and Ionic Conductivity

In this work, blends of Poly(ethylene oxide), PEO, and poly(1,6-hexanediol), PHD, were prepared in a wide composition range. They were examined by Differential Scanning Calorimetry (DSC), Polarized Light Optical Microscopy (PLOM) and Wide Angle X-ray Scattering (WAXS). Based on the results obtained, the blends were partially miscible in the melt and their crystallization was a function of miscibility and composition. Crystallization triggered phase separation. In blends with higher PEO contents both phases were able to crystallize due to the limited miscibility in this composition range. On the other hand, the blends with higher PHD contents display higher miscibility and therefore, only the PHD phase could crystallize in them. A nucleation effect of the PHD phase on the PEO phase was detected, probably caused by a transference of impurities mechanism. Since PEO is widely used as electrolyte in lithium batteries, the PEO/PHD blends were studied with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), and the effect of Li-salt concentration was studied. We found that the lithium salt preferentially dissolves in the PEO phase without significantly affecting the PHD component. While the Li-salt reduced the spherulite growth rate of the PEO phase within the blends, the overall crystallization rate was enhanced because of the strong nucleating effect of the PHD component. The ionic conductivity was also determined for the blends with Li-salt. At high temperatures (>70 °C), the conductivity is in the order of ~10−3 S cm−1, and as the temperature decreases, the crystallization of PHD was detected. This improved the self-standing character of the blend films at high temperatures as compared to the one of neat PEO.This work has received funding from Basque Government through grant IT1309-19

Unexpected structural properties in the saturation region of the odd-even effects in aliphatic polyethers: Influence of crystallization conditions

Unformatted post-print version of the accepted articleA series of aliphatic polyethers with different chain lengths (nCH2= 6 to 12, and 16) is studied employing differential scanning calorimetry and X-rays scattering. The calorimetric and structural behavior of samples crystallized from the melt is divided into the odd-even and saturation regions. In the odd-even region (nCH2 = 6 to 10), the odd samples (nCH2 = 7, and 9) show enhanced calorimetric properties (e.g., higher transition temperatures) and faster crystallization kinetics than the even ones (nCH2 = 6, 8 and 10). The odd samples crystallize in orthorhombic unit cells and the even ones in monoclinic unit cells. In the saturation region (nCH2 = 11 to 16), the calorimetric properties increase as nCH2 increases without alternation. However, unexpectedly, the nCH2 = 12 displayed a mixed structure (monoclinic + orthorhombic) instead of an orthorhombic one. Thus, a structural saturation effect (i.e., an orthorhombic unit cell) is not reached. This particular structural feature was investigated under varied thermal histories, induced by different cooling rates. The samples as synthesized (i.e., crystallized during precipitation from solution) exhibited a structural saturation effect since both nCH2 = 10 and 12 display an orthorhombic unit cell. But, the nCH2 = 10 exhibits a monoclinic unit cell, and the nCH2 = 12 a mixed structure when the samples crystallize from the melt at different rates. Only the nCH2 = 16 crystallizes in an orthorhombic unit cell, independently of the thermal history. Thus, the complex odd-even effects in these aliphatic polyethers are a function of the cooling rate from the melt and sample preparation procedures (solution or melt crystallization).We would like to thank the financial support provided by the BIODEST project; this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 778092. This work was also supported by Grant PID2020-113045GB-C21 funded by MCIN/AEI/10.13039/501100011033. This work has also received funding from the Basque Government through grant IT1309-19. R.A.P.-C is supported by the China Postdoctoral Science Foundation (2020M670462), and National Natural Science Foundation of China (NSFC) (52050410327). The support of the ALBA (2020024169) and SSRF synchrotron facility is gratefully acknowledged

Isomorphic polyoxyalkylenes copolyethers obtained by copolymerization of aliphatic diols

Isomorphism in random copolymers occurs when comonomer units can crystallize within a single crystalline lattice in the entire composition range. This ideal behavior is rare in random copolymers and only a few examples of isomorphism are found in copolyesters and copolycarbonates. In this work, we show a series of polyoxyalkylenes copolyethers obtained by copolymerization of 1,6-hexanediol and 1,12-dodecanediol which are able to crystallize in the entire composition range and display an isomorphic behavior. The copolymers were synthesized via a bulk self-condensation method at high temperature, using a thermally stable Non-Eutectic Mixture Organocatalyst (NEMO) prepared from methanesulfonic acid (MSA) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The final molar ratios of the copolyethers were calculated by 1H NMR spectroscopy and the random distribution of the two monomeric units was confirmed by 13C NMR spectroscopy. The effect of the composition of comonomer units on the crystalline structure was investigated by DSC and WAXS. The two comonomeric units along the chain can co-crystallize regardless of the composition, while displaying melting point values that vary linearly in between those of the parent homopolymers (54,9 and 84,7 °C). The crystalline reflections given by WAXS demonstrated that the two comonomers are miscible in the crystalline state and meet the general criteria to be regarded isomorphic random copolymers. Finally, a random terpolymer was synthetized from 1,6-hexanediol, 1,10-decanediol and 1,12-dodecanediol, which also shows a single melting temperature, thus demonstrating the versatility of the polymerization route employed.The authors thank the European Commission for its financial support through the projects SUSPOL-EJD 642671. Haritz Sardon and David Mecerreyes gratefully acknowledge financial support from MINECO through project POLYCE. A. J. Müller, O. Coulembier and H. Sardon also acknowledge European funding by the RISE BIODEST project (H2020-MSCA-RISE-2017-778092). The authors also thank the technical and human support provided by Mrs. Sofia Guezala (SGIker) of UPV/EHU for the NMR analysis. H. Sardon, A.J. Müller and I. Flores acknowledge funding and beam time from ALBA Synchrotron facility through the project: 2017092338 (2018). A. J. Müller gratefully acknowledges financial support from MINECO through project MAT2017-83014-C2-1-P. A. Etxeberria acknowledges financial support from the Basque Government (GIC IT-618-13). O. C. is Research Associate for the F.R.S.-FNRS. Irma Flores would like to acknowledge Conacyt (Mexico) for supporting her PhD studies with a scholarship

Electroactive 3D printable poly (3,4-ethylenedioxythiophene)-graft-poly(ε-caprolactone) copolymers as scaffolds for muscle cell alignment

Unformatted postprintThe development of tailor-made polymers to build artificial three-dimensional scaffolds to repair damaged skin tissues is gaining increasing attention in the bioelectronics field. Poly (3,4-ethylene dioxythiophene) (PEDOT) is the gold standard conducting polymer for the bioelectronics field due to its high conductivity, thermal stability, and biocompatibility; however, it is insoluble and infusible, which limits its processability into three dimensional scaffolds. Here, poly(3,4-ethylendioxythiophene)-graft-poly(ε−caprolactone) copolymers, PEDOT-g-PCL, with different molecular weights and PEDOT compositions, were synthesized by chemical oxidative polymerization to enhance the processability of PEDOT. First, the chemical structure and composition of the copolymers were characterized by nuclear magnetic resonance, infrared spectroscopy, and thermogravimetric analysis. Then, the additive manufacturing of PEDOT-g-PCL copolymers by direct ink writing was evaluated by rheology and 3D printing assays. The morphology of the printed patterns was further characterized by scanning electron microscopy and the conductivity by the four-point probe. Finally, the employment of these printed patterns to induce muscle cells alignment was tested, proving the ability of PEDOT-g-PCL patterns to produce myotubes differentiation.This work was funded by the spanish AEI-MICINN project PID2020-119026GB-I00 and Basque Government through grant IT1309-19. J. L. O.-M. thanks the Consejo Nacional de Ciencia y Tecnología (CONACyT, México) for the grant awarded no. 471837

Polymorphism in Non-Fullerene Acceptors Based on Indacenodithienothiophene

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Organic solar cells incorporating non-fullerene acceptors (NFAs) have reached remarkable power conversion efficiencies of over 18%. Unlike fullerene derivatives, NFAs tend to crystallize from solutions, resulting in bulk heterojunctions that include a crystalline acceptor phase. This must be considered in any morphology-function models. Here, it is confirmed that high-performing solution-processed indacenodithienothiophene-based NFAs, i.e., ITIC and its derivatives ITIC-M, ITIC-2F, and ITIC-Th, exhibit at least two crystalline forms. In addition to highly ordered polymorphs that form at high temperatures, NFAs arrange into a low-temperature metastable phase that is readily promoted via solution processing and leads to the highest device efficiencies. Intriguingly, the low-temperature forms seem to feature a continuous network that favors charge transport despite of a poorly order along the π–π stacking direction. As the optical absorption of the structurally more disordered low-temperature phase can surpass that of the more ordered polymorphs while displaying comparable—or even higher—charge transport properties, it is argued that such a packing structure is an important feature for reaching highest device efficiencies, thus, providing guidelines for future materials design and crystal engineering activities.This work was supported by the Ministerio de Ciencia e Innovacion/FEDER (under Ref. PGC2018-094620-A-I00 and PGC2018-095411-B-I00, CEX2019-000917-S, and PGC2018-095411-B-100) and the Basque Country Government (Ref. PIBA19-0051). S.M. is grateful to POLYMAT for the doctoral scholarship. The authors thank A. Arbe, A. Alonso-Mateo, and L. Hueso for their support and access to characterization tools. The authors also thank the technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). GIWAXS experiments were performed at BL11 NCD-SWEET beamline at ALBA Synchrotron (Spain) with the collaboration of ALBA staff. J.M and E.F.-G. acknowledge support through the European Union's Horizon 2020 research and innovation program, H2020-FETOPEN 01-2018-2020 (FET-Open Challenging Current Thinking), “LION-HEARTED,” Grant Agreement No. 828984. J.M and N.S. would like to thank the financial support provided by the IONBIKE RISE project, which received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 823989. N.S., A.K., and A.B. furthermore are grateful to the U.S. National Science Foundation (NSF) for support via Project No. 1905901 within NSF's Division of Materials Research. A.S. and M.C. acknowledge financial support by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program “HEROIC,” Grant Agreement No. 638059. This work was partially carried out at Polifab, the micro- and nanotechnology center of the Politecnico di Milano. C.M. thanks the Knut and Alice Wallenberg Foundation for funding through the project “Mastering Morphology for Solution-borne Electronics.” A.I. thanks MICINN for a Personal Técnico de Apoyo contract (PTA2017-14359-I) and gratefully acknowledge the financial support of the Basque Government (Research Groups IT-1175-19) and the MICINN (PGC2018-094548-B-I00, MCIU/AEI/FEDER, UE. Funding for open access charge: Universidade da Coruña/CISUG.Gobierno Vasco; PIBA19-0051Gobierno Vasco; IT-1175-19Estados Unidos. National Science Foundation; 190590

Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options

[EN] Poly(hydroxy acids) have been gaining increasing attention in the search for novel sustainable materials to replace petrochemical polymers in packaging applications. Poly(hydroxy acids) are polyesters that are obtained using hydroxy acids as the starting materials, which are derived from renewable resources and biowaste. These biopolymers have attracted a lot of attention since some of them will be in the near future competitive in price to polyolefins, show excellent mechanical and barrier properties, and can be potentially recycled by physical and chemical routes. Most of the current poly(hydroxy acids) are mainly prepared by ring-opening polymerization (ROP) of cyclic monomers derived from hydroxy acids. However, their direct polymerization has received much less attention, while one of the advantages of hydroxy acids resides in the presence of an electrophile and a nucleophile in a single molecule that makes them ideal A-B type monomers for self-condensation. This review focuses on the preparation of poly(hydroxy acids) by the self-condensation polymerization of hydroxy acids. Moreover, their end-of-life options are also evaluated considering not only their biodegradability but also their potential to be chemically recycledThe authors thank the European Commission (EC) for financial support through the project SUSPOL-EJDH2020-ITN-2014-642671 and the Spanish Ministry of Science and Innovation (MICI) through the projects RTI2018-097249-B-C21, MAT2017-83373-R, and MAT-2016-78527-P. S. Torres-Giner also acknowledges MICI for his Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) and the financial support received during his stay at the Institute for Polymer Materials (POLYMAT)Gabirondo, E.; Sangroniz, A.; Etxeberria, A.; Torres-Giner, S.; Sardon, H. (2020). Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options. Polymer Chemistry. 11(30):4861-4874. https://doi.org/10.1039/D0PY00088DS48614874113

Poliesterren sintesirako joera berriak: katalizatzaileen diseinutik birziklapen kimikora

El capítulo 4 está sujeto a confidencialidad por la autora. 304 p.Los poliésteres han demostrado ser un material interesante para la misión de sostenibilidad que propone Naciones Unidas en el ámbito de los "Objetivos de Desarrollo Sostenible". Una de las razones fundamentales de su elección para este fin no es sólo su capacidad de biodegradación en condiciones adecuadas, sino también su potencial de reciclaje junto con su potencial de ser preparado a partir de biomasa. Aunque este polímero podría obtenerse a partir de la biomasa y se han realizado varios esfuerzos para aumentar su reciclabilidad, la mayoría de los poliésteres producidos industrialmente están basados en el petróleo y los métodos sintéticos empleados no son lo suficientemente ecológicos teniendo en cuenta los Objetivos de Desarrollo Sostenible, ya que durante su síntesis se emplean metales de transición y procesos intensivos en energía. Aprovechando las posibilidades que ofrece esta familia de polímeros, este trabajo aborda algunos de los retos que aún son necesarios para aumentar la sostenibilidad de los materiales y procesos de síntesis del poliéster

Boosting the Reactivity of Bis-lactones to Enable Step-Growth Polymerization at Room Temperature

The development of a circular model for plastics is a major challenge, with polyesters as primary targets. Lactones are key monomers thanks to ring-opening polymerization, but their use in step-growth polymerization has remained so far scarce and challenging. Herein we report a powerful bis-(γ-lactone) (γSL) that was efficiently prepared on gram scale from malonic acid by Pd-catalyzed cycloisomerization. The γ-exomethylene moieties and the spiro structure greatly enhance its reactivity towards ring-opening and enable step-growth polymerization to proceed in a controlled manner under mild conditions. Using diols, dithiols or diamines as comonomers, a variety of regioregular (AB)n copolymers with diverse linkages and functional groups (from oxo-ester, to β-thioether lactone and β-hydroxy-lactame) have been readily prepared. Reaction modeling and monitoring revealed the occurrence of an original trans-lactonization process following the first ring-opening of γSL. This peculiar reactivity opens the way to regioregular (ABAC)n terpolymers, as illustrated by successive step-growth polymerization of γSL with a diol and a diamine