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Gonçalves Oliveira Valente da Cruz-Lopes, Luísa Paula
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- Cork Liquefaction for Polyurethane Foam ProdutionPublication . Esteves, Bruno; Dulyanska, Yuliya; Costa, Catarina; Vicente, Jose; Domingos, Idalina; Pereira, Helena; Lemos, Luis; Cruz-Lopes, LuísaCork is one of the most important forest products in Portugal. The cork processing industry is highly resource-efficient, with the only residue, cork powder, which is too minor in quantity for agglomerate production. This work studied the usage of cork powder for the production of added-value products via polyol liquefaction. Liquefactions were performed in a reactor using a mixture of polyethylene glycol (PEG 400) and glycerol as solvents, which were catalyzed by the addition of sulphuric acid. Several cork-to-solvent ratios, reaction temperatures, and reaction times were tested. Polyurethane foams were prepared by combining polyol mixtures with a catalyst, surfactant, blowing agent, and polymeric isocyanate. Mechanical tests of the produced foams were conducted, and compressive modulus of elasticity and compressive stress at 10% deformation were determined. The results show that the best conditions for obtaining high liquefaction yields are as follows: 160 ºC for 1 h; glycerol-to-PEG 400 ratio of 1:9; cork-to-solvent ratio of 1:6; and 3% H2SO4 catalyst addition. The Fourier Transform Infrared (FTIR) spectra indicated that the lignocellulosic fractions of the cork were more selectively dissolved during acidified polyol liquefaction than the suberin. With liquefied cork powder using these optimized conditions, it is possible to produce polyurethane foams with desired properties.
- Polyurethane Foams from Liquefied Eucalyptus globulus BranchesPublication . Domingos, Idalina; Fernandes, Ana Paula; Ferreira, José; Cruz-Lopes, Luísa; Esteves, BrunoCurrently, polyurethane (PU) production is completely dependent upon fossil oil, as the two primary reagents necessary for PU production, polyol and isocyanate, are derived from fossil fuels. Eucalyptus branches are waste products for most forest management companies. In this work, polyols obtained by the liquefaction of eucalyptus branches were used for foam production. The influence of the isocyanate, catalyst, surfactant, and blowing agent contents on the foam properties was studied. Overall the amount of each chemical used in the production of PU foams had a noticeable effect on the density and compressive properties. The amount of water (blowing agent) had the strongest effect and decreased the density and compressive properties because of higher foam expansion. The other chemicals increased or decreased the density and compressive stress depending on the amount used. The density of the produced foams ranged from 36 kg/m3 to 108 kg/m3, the compressive stress ranged from 15 kPa to 149 kPa, and the Young’s modulus ranged from 64 kPa to 2100 kPa. The results showed that it is possible to convert these forest residues into PU foams with properties somewhat similar to those of commercial foams, although with a lower compressive strength.
- The contribution of a portion of meat, fish and eggs for climate changePublication . Ferreira, Vicente; Domingos, Idalina; Esteves, Bruno; Cruz-Lopes, LuísaIntrodução: A mudança nos padrões alimentares dos cidadãos implicará uma pegada ambiental maior em termos de emissões de gases de efeito estufa e uso de recursos naturais. Por exemplo, dietas ricas em leite e carne, especialmente de ruminantes, estão associadas ao aumento das emissões de metano da fermentação entérica, do dióxido de carbono da deflorestação para dar origem ao pasto e do óxido nitroso da produção de ração. Objetivos: Para um consumo mais sustentável, o objetivo deste estudo foi quantificar e comparar a contribuição para as alterações climáticas de uma porção do que se come em geral, proveniente da Roda dos Alimentos, relacionados com carnes, aves, peixes e ovos, para alcançar uma dieta equilibrada e saudável. Métodos: A Avaliação do Ciclo de Vida, baseada nas normas ISO 14040/44 (2006), foi a metodologia utilizada. A análise de inventário e, posteriormente a análise de impacte foram realizadas utilizando o software SimaPro 8.5. O método escolhido para a avaliação de impacte ambiental foi o IPCC 2013 GWP 100a. Resultados: Os resultados mostram que uma porção de cavala (peixe) apresenta a pegada ecológica inferior seguida da porção de bacalhau, frango, lombo de porco, ovos, lagosta e bife de vaca, respetivamente. Conclusões: A principal conclusão deste estudo é que a avaliação do impacte de ciclo de vida usando o método IPCC 2013 GWP 100a, pode ajudar as pessoas a escolherem os melhores alimentos para uma refeição mais amiga do ambiente, ajudando a mitigar as alterações climáticas.
- Caracterização do Engaço da Uva e Avaliação do seu Potencial como Matéria‐Prima LenhocelulósicaPublication . Prozil, Sónia; Mendes, Joana; Evtuguin, Dmitry; Cruz-Lopes, LuísaResumo O presente estudo avalia a composição química detalhada do engaço da uva de modo a encontrar novas formas para a sua valorização. O engaço da uva é um subproduto vinícola de origem lenhocelulósica, com 30-31% de celulose, 21% de hemicelulose, 17-18% de lenhina, 15-16% de taninos e cerca de 6,0% de proteínas. A análise dos monossacarídeos mostrou que, a seguir à celulose, a xilana é o segundo polissacarídeo mais abundante no engaço (ca. 12%). A celulose foi isolada pelo método Kürscher e Hoffer e foi caracterizada por difração de raios-X (DRX). Esta análise revelou a existência de uma célula unitária típica de celulose I com um elevado grau de cristalinidade (ca. 75%). Também foi possível verificar uma elevada abundância de compostos extratáveis em água (ca. 24%), atribuídos principalmente a sais inorgânicos solúveis, taninos hidrolisáveis e pectinas. A lenhina Klason foi caracterizada por espectroscopia de infravermelho e espectroscopia de ressonância magnética tendo-se verificado tratar-se de uma lenhina do tipo HGS, com predominância de unidades guaiacilo.
- Production of Polyurethane Foams from Bark WastesPublication . Cruz-Lopes, Luísa; Rodrigues, Liliana; Domingos, Idalina; Ferreira, José; Lemos, Luís Teixeira de; Esteves, BrunoCurrently, the polyurethanes industry is dependent on fossil resources to obtain their basic raw materials (polyols and isocyanate), as these are obtained from petroleum products. The aim of this work was to use biopolyols from liquefied Pseudotsuga (Pseudotsuga menziesii) and Turkey oak (Quercus cerris) barks for the production of polyurethane foams and optimize the process. Liquefaction was done with glycerol catalyzed by KOH. Foams were produced following different formulations and using biopolyols from both barks. Subsequently, the foams were characterized according to their mechanical properties and the reaction of the foam formation was monitored by FTIR-ATR. The results show that it is possible to produce polyurethane foams using bio-based polyols and the liquefaction conditions are very important because they influence the characteristics of biopolyols and, consequently the characteristics of the foams. However, the process has to be further optimized so that it can obtain better quality foams
- Water-related properties of Pinus pinaster wood treated by different methodsPublication . Domingos, Idalina; Ferreira, José; Cruz-Lopes, Luísa; Esteves, BrunoA study was made of water-related properties of Pinus pinaster wood impregnated with paraffin or modified by heat treatment or furfurylation. Treated woods were submerged in water for periods ranging from 2 to 1680 hours. Water absorption, swelling, and dimensional stability in the radial and tangential directions – expressed as Anti-Shrinking Efficiency (ASE) – were determined. Water absorption increased with time, reaching approximately 140% after 1680 h for untreated and heat-treated wood, and 60% for paraffinated and furfurylated wood. The rate of swelling differed between the first hours of soaking and after prolonged immersion. The final swelling was approximately 9% and 6% for untreated pine, 8% and 4% for paraffinated pine, 5.5% and 3% for heat-treated pine and 2.5% and 1% for furfurylated pine (in the tangential and radial directions respectively). At the end of the soaking test, furfurylated pine had the best ASE of approximately 80% and 70% in the tangential and radial directions respectively, followed by heat-treated pine with 44% and 34%, and paraffinated wood with 35% and 13%. [
- Enhancing Liquefaction Efficiency: Exploring the Impact of Pre-Hydrolysis on Hazelnut Shell (Corylus avellana L.)Publication . Cruz-Lopes, Luísa; Duarte, Joana; Dulyanska, Yuliya; Guiné, Raquel; Esteves, BrunoHazelnut shells (HS), scientifically known as Corylus avellana L. shells, are waste produced by companies that process nuts. The main objective of this study was to find an efficient way to maximize the chemical potential of HS by solubilizing the hemicelluloses, which could then be used to recover sugars and, at the same time, increase the lignin content of this material to produce adhesives or high-strength foams. In order to optimize the pre-hydrolysis process, two different temperatures (160 and 170 °C) and times varying from 15 to 180 min were tested. All the remaining solid materials were then liquefied using polyalcohols with acid catalysis. The chemical composition of hazelnut shells was determined before and after the pre-hydrolysis. All of the process was monitored using Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) by determining the spectra of solids and liquids after the pre-hydrolysis and liquefaction steps. The highest solubilization of hazelnut shells was found for 170 °C and 180 min, resulting in a 25.8% solubilization. Chemical analysis after the hydrolysis process showed a gradual increase in the solubilization of hemicelluloses as both the temperature and time of the reactor were increased. Simultaneously, the percentages of α-cellulose and lignin in the material also increased with rises in temperature and duration. FTIR-ATR allowed for the detection of significant spectral changes in the hazelnut shells from their initial state to the solid residue and further into the liquefied phase. This confirmed that pre-hydrolysis was effective in enhancing the chemical composition of the material, making it more suitable for the production of adhesives, polyurethane foams, or in the production of bioplastics and composite materials, combined with other biopolymers or synthetic polymers to enhance the mechanical properties and biodegradability of the resulting materials.
- Edible Insects: Perceptions of Marketing, Economic, and Social Aspects among Citizens of Different CountriesPublication . Guiné, Raquel; Florença, Sofia De Guiné E; Costa, Cristina Amaro Da; Correia, Paula; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Campos, Sofia; Anjos, Ofélia; Bartkiene, Elena; Djekic, Ilija; Matran, Irina M.; Čulin, Jelena; Klava, Dace; Chuck-Hernández, Cristina; Korzeniowska, Malgorzata; Boustani, Nada M.; Papageorgiou, Maria; Gutiérrez, Bernardo Prieto; Černelič-Bizjak, Maša; Damarli, Emel; Ferreira, VanessaBecause edible insects (EI) have been, in recent years, recommended as a nutritious animal protein food with enormous environmental advantages over other sources of animal protein for human consumption, studies aimed at investigating the consumer perspective have become more prominent. Hence, this study intended to examine the perceptions of participants from different countries about the commercialization and economic and social impacts of edible insects. The study was made using a questionnaire survey, and data were collected in Brazil, Croatia, Greece, Latvia, Lebanon, Lithuania, Mexico, Poland, Portugal, Romania, Serbia, Slovenia, Spain, and Turkey. The final number of received answers was 7222 participants. For the treatment of the results, different statistical techniques were used: factor analysis, internal reliability by Cronbach’s alpha, cluster analysis, ANOVA to test differences between groups, and Chi-square tests. The results obtained confirmed the validity of the scale, constituted by 12 out of the 14 items initially considered, distributed by 4 factors: the first related to the economic impact of EIs, the second related to the motivation for consumption of EIs, the third related to the places of purchase of EIs, and the fourth corresponding to a question presented to the participants as a false statement. A cluster analysis allowed identifying three clusters, with significant differences between them according to all the sociodemographic variables tested. Also, it was found that the participants expressed an exceptionally high level of agreement with aspects such as the difficulty in finding EIs on sale, knowledge acting as a strong motivator for EI consumption, and the role of personalities and influencers in increasing the will to consume EIs. Finally, practically all sociodemographic variables were found to be significantly associated with perceptions (country, sex, education, living environment, and income), but not age. In conclusion, the perceptions about EI commercialization were investigated and revealed differences among samples originating from different countries. Moreover, the sociodemographic characteristics of the participants were found to be strongly associated with their perceptions.
- Integrated utilization of grape skins from white grape pomacesPublication . Mendes, Joana A.S.; Xavier, Ana M.R.B.; Evtuguin, Dmitry V.; Cruz-Lopes, LuísaAn approach for the integrated utilization of grape skins from white grape pomaces has been proposed. This consists of consecutive or simultaneous extraction of grape skins with neutral organic solvent and water under reflux. Organic extract is a valuable raw material for the isolation of oleanolic acid. The aqueous extract (ca 50%, w/w) is composed of essentially hexoses and suitable for the high yield (till 51%) bioethanol production at a maximum specific cell growth rate (μmax) of 0.29 h−1. The remained extracted grape skins are the complex of structural polysaccharides embedded into cutinous matrix. Extracted grape skins were shown to be a prospective raw material for the production of low-density boards (d ≤ 0.40) for insulation needs. The boards produced from grape skins and bind of 8% urea–formaldehyde resin revealed reasonable tensile strength (0.4 MPa) and a low thermal conductivity (0.09–0.12 W (m K)−1) over a wide range of temperatures (40–200 °C).
- Plastic Food Packaging: Perceptions and Attitudes of Portuguese Consumers about Environmental Impact and RecyclingPublication . Weber Macena, Morgana; Carvalho, Rita; Cruz-Lopes, Luísa; Guiné, Raquel P. F.The use of plastics for packaging has some advantages, since they are flexible and inexpensive. However, most plastics are of single use, which, combined with low recycling or reuse ratios, contributes substantially to environmental pollution. This work is part of a project studying the habits of Portuguese citizens concerning plastic food packaging and focuses on aspects related to sustainability. The survey was carried out via an online questionnaire about sustainability, recycling, and knowledge of the effects of plastic materials or their residues on the environment. The results were obtained based on a statistical analysis of the data. The participants tend to think about the negative impact of plastic packages on the environment; 39% sometimes do not buy plastic; and 30% try to look for alternatives. A substantial fraction, 81%, support the avoidance of plastic utensils and reduction in the use of plastic bags. Most participants have a good knowledge of recycling and strongly agree with the use of recycled materials, and 87% of respondents practice separation of different types of waste for recycling. Changing plastic consumption habits has not been an easy task. Nevertheless, it is expected that society will increasingly move toward sustainable habits, questioning its actions and considering their impact on the environment.