Characterization of Wood‑based Industrial Biorefinery Lignosulfonates and Supercritical Water Hydrolysis Lignin

Understanding the properties of any particular biorefinery or pulping residue lignin is crucial when choosing the right lignin for the right end use. In this paper, three different residual lignin types [supercritical water hydrolysis lignin (SCWH), ammonium lignosulfonate (A-LS), and sodium lignosulfonate (S-LS)] were evaluated for their chemical structure, thermal properties and water vapor adsorption behavior. SCWH lignin was found to have a high amount of phenolic hydroxyl groups and the highest amount of beta-O-4 linkages. Combined with a low ash content, it shows potential to be used for conversion into aromatic or platform chemicals. A-LS and S-LS had more aliphatic hydroxyl groups, aliphatic double bonds and C=O structures. All lignins had available C-3/C-5 positions, which can increase reactivity towards adhesive precursors. The glass transition temperature (T-g) data indicated that the SCWH and S-LS lignin types can be suitable for production of carbon fibers. Lignosulfonates exhibited considerable higher water vapor adsorption as compared to the SCWH lignin. In conclusion, this study demonstrated that the SCWH differed greatly from the lignosulfonates in purity, chemical structure, thermal stability and water sorption behavior. SCWH lignin showed great potential as raw material for aromatic compounds, carbon fibers, adhesives or polymers. Lignosulfonates are less suited for conversion into chemicals or carbon fibers, but due to the high amount of aliphatic hydroxyl groups, they can potentially be modified or used as adhesives, dispersants, or reinforcement material in polymers. For most value-adding applications, energy-intensive purification of the lignosulfonates would be required.Open access funding provided by Linnaeus University. Venla Hemmila and Stergios Adamopoulos would like to thank the Knowledge Foundation for the financial support (project titled "New environment-friendly board materials", 2015-2019). Arantxa Eceiza thanks the Basque Government (IT776-16) and SgiKer General Services of the University of the Basque Countr

Nonwoven Mats Based on Segmented Biopolyurethanes Filled with MWCNT Prepared by Solution Blow Spinning

To prepare nonwoven mats constituted by submicrometric fibers of thermally responsive biopolyurethanes (TPU) modified with multiwalled carbon nanotubes (MWCNT), solution blow spinning (SBS) was used. The TPU was the product of synthesis using poly(butylene sebacate)diol, PBSD, ethyl ester L-lysine diisocyanate (LDI), and 1,3-propanediol (PD) (PBSe:LDI:PD) as reactants. TPU was modified by adding different amounts of MWCNT (0, 0.5, 1, 2, and 3 wt.%). The effect of the presence and amount of MWCNT on the morphology and structure of the materials was studied using field-emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR), respectively, while their influence on the thermal and electric behaviors was studied using differential scanning calorimetry (DSC) and capacitance measurements, respectively. The addition of MWCNT by SBS induced morphological changes in the fibrous materials, affecting the relative amount and size of submicrometric fibers and, therefore, the porosity. As the MWCNT content increased, the diameter of the fibers increased and their relative amount with respect to all morphological microfeatures increased, leading to a more compact microstructure with lower porosity. The highly porous fibrous morphology of TPU-based materials achieved by SBS allowed turning a hydrophilic material to a highly hydrophobic one. Percolation of MWCNT was attained between 2 and 3 wt.%, affecting not only the electric properties of the materials but also their thermal behavior.This research was funded by the Fondos de Investigación de Fco. Javier González Benito, política de reinversión de costes generales, Universidad Carlos III de Madrid [2012/00130/004], the Acción Estratégica en Acción Estratégica en Materiales nanocompuestos multifuncionales, Universidad Carlos III de Madrid [2011/00287/003], and the Project PID2020-112713RB-C22–C21 supported by AEI [Ministerio de Ciencia e Innovación of Spain], the University of the Basque Country (UPV/EHU) and (GIU18/216 Research Group)

Copolímeros de poliuretano del tipo poli[(hexametilen-carbamato- butanodiol)-co-(carbonato-co-éster)]

Resumen Los poliuretanos segmentados termoplástico elastoméricos (PUSTE) comprenden una familia de materiales muy versátiles debido a su potencial empleo en diversos campos tales como biomedicina. Entre los PUSTE los formados por policarbonatos dioles y diisocianatos alifáticos son especialmente atractivos debido a su bioestabilidad y biocompatibilidad. En este trabajo se presentan los resultados del análisis morfológico y conducta mecánica de una familia de PUSTEs formados por 1,6-hexametilen diisocianato (HDI), 1,4-butanodiol (BD) y un copolímero cauchoso de policaprolactona y polihexametilen carbonato diol, PCL-b-PHMC-b-PCL, sintetizados con distinta relación entre bloques rígidos (HDI-BD) y copolímero cauchoso.Segmented thermoplastic polyurethane elastomers (PUSTE) comprise a family of very versatile materials with large potential for their applicability in different fields such as biomedicine. Among the PUSTEs the ones formed by polycarbonates diols and aliphatic diisocyanates are especially attractive due to their bioestability and biocompativility. In this work we present the results of morphological and mechanical characterization of different PUSTEs formed by 1,6-hexamethyene diisocyanate, 1,4-butanediol and a copolymer of polycaprolactone and polyhexamethylene carbonate diol, PCL-b-PHMC-b-PCL, synthesized with different ratios between rigid (HDI-BD) segments and the rubbery copolymer

Water Uptake Behavior and Young Modulus Prediction of Composites Based on Treated Sisal Fibers and Poly(Lactic Acid)

The main aim of this work was to study the effect of sisal fiber surface treatments on water uptake behavior of composites based on untreated and treated fibers. For this purpose, sisal fibers were treated with different chemical treatments. All surface treatments delayed the water absorption of fibers only for a short time of period. No significant differences were observed in water uptake profiles of composites based on fibers with different surface treatments. After water uptake period, tensile strength and Young modulus values of sisal fiber/poly(lactic acid) (PLA) composites were decreased. On the other hand, composites based on NaOH + silane treated fibers showed the lowest diffusion coefficient values, suggesting that this treatment seemed to be the most effective treatment to reduce water diffusion rate into the composites. Finally, Young modulus values of composites, before water uptake period, were predicted using different micromechanical models and were compared with experimental data.The authors are grateful for the financial support from the Basque Country Government in the frame of Consolidated Groups (IT-776-13) and Elkartek 2015 FORPLA3D project. Technical and human support provided by SGIker (Universidad del Pais Vasco-Euskal Herriko Unibertsitatea (UPV/EHU), Ministerio de Economia y Competitividad (MINECO), Gobierno Vasco-Eusko Jaurlaritza (GV/EJ), European Regional Development Fund (ERDF) and European Science Foundation (ESF)) is also gratefully acknowledged

Microwave-assisted extraction of cellulose nanocrystals from almond (Prunus amygdalus) shell waste

Almond (Prunus amygdalus) is one of the most common tree nuts on a worldwide basis. This nut is highly regarded in the food and cosmetic industries. However, for all these applications, almonds are used without their shell protection, which is industrially removed contributing approximately 35-75% of the total fruit weight. This residue is normally incinerated or dumped, causing several environmental problems. In this study, a novel cellulose nanocrystal (CNCs) extraction procedure from almond shell (AS) waste by using microwave-assisted extraction was developed and compared with the conventional approach. A three-factor, three-level Box-Behnken design with five central points was used to evaluate the influence of extraction temperature, irradiation time, and NaOH concentration during the alkalization stage in crystallinity index (CI) values. A similar CI value (55.9 +/- 0.7%) was obtained for the MAE process, comprising only three stages, compared with the conventional optimized procedure (55.5 +/- 1.0%) with five stages. As a result, a greener and more environmentally friendly CNC extraction protocol was developed with a reduction in time, solvent, and energy consumption. Fourier transform infrared (FTIR) spectra, X-ray diffractogram (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) images, and thermal stability studies of samples confirmed the removal of non-cellulosic components after the chemical treatments. TEM images revealed a spherical shape of CNCs with an average size of 21 +/- 6 nm, showing great potential to be used in food packaging, biological, medical, and photoelectric materials. This study successfully applied MAE for the extraction of spherical-shaped CNCs from AS with several advantages compared with the conventional procedure, reducing costs for industry.This work was supported by Conselleria de Educacion (Spain) (APOSTD/2016/093 Postdoctoral Research Training Grant), the Spanish Ministry of Economy, Industry and Competitiveness (MAT2017-84909-C2-1-R), and the University of the Basque Country (UPV/EHU) (GIU18-216)

Advances in Waterborne Polyurethane and Polyurethane-Urea Dispersions and Their Eco-friendly Derivatives: A Review

Polyurethanes and polyurethane-ureas, particularly their water-based dispersions, have gained relevance as an extremely versatile area based on environmentally friendly approaches. The evolution of their synthesis methods, and the nature of the reactants (or compounds involved in the process) towards increasingly sustainable pathways, has positioned these dispersions as a relevant and essential product for diverse application frameworks. Therefore, in this work, it is intended to show the progress in the field of polyurethane and polyurethane-urea dispersions over decades, since their initial synthesis approaches. Thus, the review covers from the basic concepts of polyurethane chemistry to the evolution of the dispersion’s preparation strategies. Moreover, an analysis of the recent trends of using renewable reactants and enhanced green strategies, including the current legislation, directed to limit the toxicity and potentiate the sustainability of dispersions, is described. The review also highlights the strengths of the dispersions added with diverse renewable additives, namely, cellulose, starch or chitosan, providing some noteworthy results. Similarly, dispersion’s potential to be processed by diverse methods is shown, evidencing, with different examples, their suitability in a variety of scenarios, outstanding their versatility even for high requirement applications.This research was funded by the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), the Spanish Ministry of Science, Innovation and Universities and European Union (MICINN/EU/FEDER) (MAT2016-76294-R and PID2019-105090RB-I00). Also, the Foundation for Science and Technology (FCT, Portugal) funded by financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020). National funding by FCT- Foundation for Science and Technology, through the institutional scientific employment program-contract with I.F. Valor Natural project for the contract of A.S.-E. (Mobilizer Project Norte-01-0247-FEDER-024479)

Modification of Pea Starch and Dextrin Polymers with Isocyanate Functional Groups

Pea starch and dextrin polymers were modified through the unequal reactivity of isocyanate groups in isophorone diisocyanate (IPDI) monomer. The presence of both urethane and isocyanate functionalities in starch and dextrin after modification were confirmed by Fourier transform infrared spectroscopy (FTIR) and C-13 nuclear magnetic resonance (C-13 NMR). The degree of substitution (DS) was calculated using elemental analysis data and showed higher DS values in modified dextrin than modified starch. The onsets of thermal degradation and temperatures at maximum mass losses were improved after modification of both starch and dextrin polymers compared to unmodified ones. Glass transition temperatures (T-g) of modified starch and dextrin were lower than unmodified control ones, and this was more pronounced in modified dextrin at a high molar ratio. Dynamic water vapor sorption of starch and dextrin polymers indicated a slight reduction in moisture sorption of modified starch, but considerably lower moisture sorption in modified dextrin as compared to that of unmodified ones.Reza Hosseinpourpia and Stergios Adamopoulos thank VINNOVA, Swedish Governmental Agency for Innovation Systems (VINNMER Marie Curie Incoming project, grant No. 2015-04825). Arantzazu Santamaria-Echart and Arantxa Eceiza wish to acknowledge the financial support from the Basque Government in the frame of Grupos Consolidados (IT-776-13) and SGIker from the University of the Basque Country for their Technical support

3D printing of customized all-starch tablets with combined release kinetics

[EN] Starch-based tablets with tailored releases were prepared by 3D printing using a hydrophobic drug. The importance of the origin of the excipient in the inks and tablets was analyzed. Besides, the effect of the geometry of the tablet on the drug release profile was also evaluated. The rheological properties of the inks was influenced by the botanic origin of the starch. Consequently, tablets presented different microporous structure and particular compression and swelling behaviors. Normal maize starch showed a non-well-defined porous morphology, not being able to form a stable structure whereas, waxy maize and potato starches exhibited a well-defined porous structure and were both able to maintain their integrity after long time immersion. Finally, tablets combining different starches and geometries were printed tailoring the drug release from 10 min to 6 h and designing two-steps profiles. The applicability of the developed 3D printed drug release systems in personalized therapies was demonstrated.Financial support from the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), from the Basque Government in the frame of Elkartek KK-2020/00053 and PIBA2020-1-0041 and from Spanish Ministry of Science and Innovation and Spanish State Research Agency (MCIN/AEI/10.13039/501100011033) in the frame of PID2019-105090RB-I00 project, are gratefully acknowledged. Moreover, we are grateful to the Macrobehavior-Mesostructure-Nanotechnology SGIker unit of the UPV/EHU. K. González thanks the University of the Basque Country for the grant “Contratación de doctores recientes hasta su integración en programas de formación postdoctoral en la UPV/EHU «DOKBERRI» 2020-I” (DOCREC20/07)

Superabsorbent bacterial cellulose spheres biosynthesized from winery by-products as natural carriers for fertilizers

[EN]Soil contamination, sustainable management of water resources and controlled release of agrochemicals are the main challenges of modern agriculture. In this work, the synthesis of sphere-like bacterial cellulose (BC) using agitated culture conditions and Komagateibacter medellinensis bacterial strain ID13488 was optimized and characterized from grape pomace (GP). First, a comparative study was carried out between agitated and static cultures using different nitrogen sources and applying alternative GP treatments. Agitation of the cultures resulted in higher BC production yield compared to static culture conditions. Additionally, Water holding capacity (WHC) assays evidenced the superabsorbent nature of the BC biopolymer, being positively influenced by the spherical shape as it was observed an increase of 60% in contrast to the results obtained for the BC membranes under static culture conditions. Moreover, it was found that sphere-like BCs were capable of retaining urea up to 375% of their dry weight, rapidly releasing the fertilizer in the presence of water. According to our findings, sphere-like BCs represent suitable systems with great potential for actual agricultural hazards and grape pomace valorisation.Financial support from the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), from the Basque Government in the frame of Elkartek KK-2020/00053 and PIBA2020-1-0041 and from Spanish Ministry of Science, Innovation and Universities and European Union (MICINN/EU/FEDER) in the frame of MAT2016-76294-R and PID2019-105090RB-I00 projects, are gratefully acknowledged. The authors also thank the technical support and personnel provided by the Servicio de Lipidómica y Metabolomica of the SGIKER (UPV/EHU,MICINN, GV/E.G., ESF) and the Phytotron Service of UPV/EHU. Moreover, are grateful to the Macrobehavior-Mesostructure-Nanotechnology SGIker unit of the UPV/EHU. Díaz-Ramírez J wishes to acknowledge the Department of Agriculture, Fisheries and Food policy of the Basque Government for the PhD grant (00020-PIT2019-22)

Development of a Novel Biobased Polyurethane Resin System for Structural Composites

Polyurethanes are gaining increasing interest for their use as structural components subjected to cyclic loads, such as leaf springs. Thermoset polyurethane (PUR) based technology offers some advantages, such as fatigue resistance, low viscosity, and fast curing. However, current PUR formulations present two major drawbacks: their petrochemical origin and high reactivity. The aim of this work was to develop a novel biobased PUR (BIO-PUR) with the required mechanical properties and processability for manufacturing structural composites by resin transfer moulding (RTM). For this purpose, a high functionality and high hydroxyl index castor-oil-based polyol was used combined with a biobased glycerol (BIO-Gly) to increase the crosslinking density and improve the final properties of the BIO-PUR. The viscosity and reactivity of the different systems were studied by means of rheology tests and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied by dynamic mechanical analysis (DMA) and flexural tests. Furthermore, the RTM process of a representative part was simulated and validated through the manufacturing and testing of plates. The properties of the BIO-PUR resin systems were strongly influenced by the addition of biobased glycerol and its effect on the crosslinking density. The combination of a high functionality and hydroxyl index biobased polyol with the biobased glycerol resulted in a high-performance BIO-PUR with the required reactivity and final properties for structural applications.This research was funded by the Basque Government through the ELKARTEK 2021 (Project NEOMAT KK-2021/00059) and in the frame of Grupos Consolidados (IT-1690-22) and by the University of the Basque Country (UPV/EHU) in the frame of GIU18/216 Research Group