Urethanes and polyurethanes from suberin 2: synthesis and characterization

Polyurethanes based on suberin from cork of Quercus suber L. and conventional isocyanate monomers were prepared and fully characterized in terms of both structure (FTIR and 1 H NMR spectroscopy) and thermal properties (differential scanning calorimetry and thermogravimetric analysis). Two fractions were systematically isolated, namely (i) methylene-chloride soluble products, which corresponded to linear and branched macromolecules and (ii) methylene-chloride insoluble products, representing the crosslinked material. The structures of these polymers were regular and no appreciable side reactions were detected. DSC analyses provided information about the glass transition temperature of both fractions and this parameter was correlated with the stiffness of the isocyanate used. The TGA of these polyurethanes showed that they started to degrade at about 175°C and that the residue at 400°C was around 50%. The highest amounts of insoluble fractions, as well as the highest Tgs, were reached when an initial [NCO]/[OH] of unity was used.info:eu-repo/semantics/publishedVersio

Cork suberin as a new source of chemicals.: 1. isolation and chemical characterization of its composition

Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1 H- and 13C-NMR, gas chromatogra phy coupled with mass spectrometric (GC–MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be v-hydroxymonocarboxylates, a,v-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.info:eu-repo/semantics/publishedVersio

Polyoxometalates as mediators in the laccase catalyzed delignification

The polyoxometalate (POM)-laccase catalytic system was applied for the first time to aerobic delignification of kraft pulps at moderate (40-60 degreesC) temperatures. Laccase was found to readily catalyze the re-oxidation of different kinds of polyoxometalates, including those, which cannot be re-oxidized by dioxygen even at high temperatures (PMo11V1, SiW11V1. etc.). This allows a sequence of catalytic redox cycles similar to that in the laccase-mediator system (LMS) where electrons are transferred from the substrate (lignin) via POM and laccase to oxygen. Results obtained showed that the POM-laccase system could decrease kappa number of eucalypt kraft pulp from 13.7 to 8.5 though the reaction rate is relatively slow. Among different POM used, SiW11V showed the best results. The effect of the process variables on the delignification was studied. The best results in delignification of eucalypt pulp were obtained at 60 degreesC, oxygen pressure of 5 bar, pH 6.3, SiW11V concentration of 4.2 mM and laccase concentration of 0.65 U/ml. The reaction temperature appears to be one of the crucial factors in the achievement of a delignification rate acceptable for practical application. (C) 2001 Elsevier Science B.V. All rights reserved

Isolation and characterization of a lignin-like polymer of the cork of Quercus suber L

A lignin-like polymer was successfully extracted from the cork of Quercus suber L. using an organosolv-based technique. This material was characterized by elemental analysis, functional group analysis, nitrobenzene oxidation followed by HPLC analysis of the oxidation products, FTIR and liquid I3C NMR. The evidence thus obtained indicated that the extracted material was composed mainly of a lignin-like polymer covalently bound to residual aliphatic structures which are not present in common lignins and which have been assigned to suberin. The latter is likely to be attached to the oxygenated side chains of the phenolic polymer but bonding through the aromatic ring can also be envisaged. No residual carbohydrates were detected. The phenolic polymer, composed mainly of guaiacyl-type units and small amounts of syringyl-type units, had a low methoxy content and a high degree of condensation. This polymer showed the presence of a fraction containing CeCn units with n < 3 or even n < 2.info:eu-repo/semantics/publishedVersio

Cork suberin as an additive in offset lithographic printing inks

Suberin oligomers, isolated from cork (Quercus suber L.), were used as additives in ‘Waterless’ and vegetable-oil ink formulations, in the range of 2–10% w/w. The rheological behaviour of the suberin oligomers as well as of the inks, with and without suberin, were investigated as a function of temperature. It was shown that the addition of suberin induces a decrease of viscosity of both inks. The tack of pristine inks, suberin oligomers and their mixtures were determined at different temperatures: the variation of this parameter as a function of time provided information about the drying kinetics of these formulations. The tack of the ‘Waterless’ ink was found to increase with the introduction of suberin, whereas that of vegetable-oil based counterparts decreased. All the trends observed were interpreted in terms of the differences in composition between the two types of inks. Preliminary printing tests were carried out with the various suberin-containing inks.info:eu-repo/semantics/publishedVersio

Polyoxometalates as promoters of laccase-assisted reactions

A synergistic effect of polyoxometalate and laccase benzenediol:oxygen oxidoreductase, EC 1.10.3.2 has been observed in the aerobic oxidation of a hydrazonaphthalene type colorant. The considerable increase in the decolorization rate of Solophenyl Blue GL dye with the new catalytic system composed by laccase and heptamolybdopentovanadophosphate heteropolyanion, when compared with the treatment with enzyme or heteropolyanion alone, was tentatively explained by the redox mediation action of the heteropolyanion

Novel cellulose-based composites based on nanofibrillated plant and bacterial cellulose: recent advances at the University of Aveiro - a review

The development of (nano)materials based on the renewable cellulose is a challenge. The present article provides a brief overview of the recent research efforts carried out at the CICECO Laboratory of the University of Aveiro on the development of novel composites based on nanofibrillated plant and bacterial cellulose embedded in natural and synthetic polymeric matrices such as poly(lactic acid), chitosan, starch, and pullulan. These materials have high potential for applications in packaging, paper coating, organic electronics, and biomedical products and devices

BIOREF : Laboratório colaborativo para as biorrefinarias

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: A investigação multidisciplinar, o desenvolvimento e a inovação são pilares fundamentais para alterar o verdadeiro paradigma da economia baseada em recursos fósseis, de modo a conceber e implementar novas economias e mercados orientados para a utilização sustentável da biomassa. De modo a contribuir para uma economia de (muito) baixo carbono e gerar novas cadeias de valor através da utilização sustentável de diferentes tipos de biomassa e biorresíduos, criação de empregos e impulsionar a bioeconomia baseada em recursos sustentáveis como alternativa aos recursos fósseis, foi criado o Laboratório Colaborativo (CoLAB) BIOREF. O BIOREF é uma entidade orientada para o mercado, concentrando as suas atividades no desenvolvimento, exploração, transferência e/ou venda de direitos de Propriedade Intelectual de novas tecnologias, produtos e serviços. O impacto a curto e longo prazo na economia nacional e na criação de empregos será alcançado pela excelência científica que opera num ambiente inspirador e inovador de I&D&I. Isto é feito, através da criação de novas ligações com as partes interessadas nacionais e europeias para identificar os desafios e necessidades para a implantação de biorrefinarias sustentáveis (económicas, ambientais e sociais) rumo a uma economia com baixo teor de carbono.ABSTRACT: Multidisciplinary research, development and innovation are required to change the actual fossil-based economy paradigm, to design and implement new economies and markets, oriented for the sustainable use of biomass.In order to contribute to a (very) low carbon economy and generate new value chains through the sustainable use of different types of biomass and biowaste, create jobs and boost the sustainable resource-based bioeconomy as an alternative to fossil resources, the Collaborative Laboratory (CoLAB)- BIOREF was created. BIOREF is a market-oriented entity concentrating its activities on the development, exploitation, transfer, and/or selling rights of Intellectual Property of novel technologies, products and services. It will be done in a strong collaboration with BIOREF associates but oriented also on the national and international industrial biomass sector. Short- and long-term impact on national economy and jobs creation will be achieved by the scientific excellence operating in inspiring, innovative R&D&I environment. It will be done, by creating new and enforcing the existing links with national and European stakeholders to identify the challenges and needs for the deployment of sustainable (economic, environmental and social) biorefineries towards to a low-carbon economy.info:eu-repo/semantics/publishedVersio