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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

An evaluation of school readiness in an informal settlement

Naidoo, Balendran 06 1900 (has links)
School readiness is a stage in a child's development when he learns easily and effectively. A child who is not yet ready for school on school entry is already at a disadvantage in the formal learning situation. This in itself can affect his school performance in the later years. The researcher, being a primary school teacher noticed that the children from the informal settlements that had no pre-school intervention arrived at school unready to learn. This investigation set out to evaluate the school readiness of children from an informal settlement without a pre-school programme. The school readiness of these children were compared against children from an informal settlement with a pre-school programme. Test and questionnaires were used to determine the five year olds' school readiness. The researcher used the idiographic method of research. The findings of the research were based on the interpretations of the tests and questionnaires. / Educational Studies / M. Ed. (with specialisation in Guidance and Counselling)
252

State-of-the-art practices being reported by the PRME champions group: a reference to advance education for sustainable development

Ghizzi, Mariana Reis de Assumpção 28 May 2018 (has links)
Submitted by Mariana Assumpcao (maghizzi@gmail.com) on 2018-08-29T03:35:46Z No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_Mariana Assumpcao_2018.pdf: 4548141 bytes, checksum: 8ed554ba741dffca269c8a36802c13ac (MD5) / Rejected by Simone de Andrade Lopes Pires (simone.lopes@fgv.br), reason: Prezada Mariana, Recebemos o seu trabalho na biblioteca mas será necessário fazer alguns ajustes. Estou encaminhando por e-mail as alterações necessárias. Por favor, faça as alterações e submeta novamente o trabalho na biblioteca digital. Atenciosamente Simone - SRA on 2018-08-30T20:17:31Z (GMT) / Submitted by Mariana Assumpcao (maghizzi@gmail.com) on 2018-08-31T19:26:18Z No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_Mariana Assumpcao_2018.pdf: 4547611 bytes, checksum: 49aad4c70da4e8b21919f40dcb9dec70 (MD5) / Rejected by Simone de Andrade Lopes Pires (simone.lopes@fgv.br), reason: Prezada Mariana, Recebemos o trabalho aplicado submetido a biblioteca digital, mas o trabalho não tem as alterações solicitadas. Por favor, submeta novamente o trabalho com as alterações. Atenciosamente, Simone de A Lopes Pires SRA on 2018-09-03T19:47:18Z (GMT) / Submitted by Mariana Assumpcao (maghizzi@gmail.com) on 2018-09-03T20:00:26Z No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_Mariana Assumpcao_2018.pdf: 4547611 bytes, checksum: 49aad4c70da4e8b21919f40dcb9dec70 (MD5) / Rejected by Simone de Andrade Lopes Pires (simone.lopes@fgv.br), reason: Boa Tarde Mariana. Por favor, verifique o trabalho que está submetendo. Continua subindo o arquivo errado. Atenciosamente, Simone de A Lopes Pires SRA on 2018-09-03T21:50:12Z (GMT) / Submitted by Mariana Assumpcao (maghizzi@gmail.com) on 2018-09-04T16:36:14Z No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_2018.pdf: 4552208 bytes, checksum: 88fc40ea635711c491b70fdfaa59faf9 (MD5) / Rejected by Simone de Andrade Lopes Pires (simone.lopes@fgv.br), reason: Boa Tarde Mariana, Verifiquei que não há no seu trabalho um resumo em português, Por favor, acrescente o resumo e submeta novamente o trabalho para liberação. Atenciosamente, Simone on 2018-09-04T18:03:54Z (GMT) / Submitted by Mariana Assumpcao (maghizzi@gmail.com) on 2018-09-04T19:01:49Z No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_2018.pdf: 4587968 bytes, checksum: 9f93d7aab79b6eeafed4e925d67c24f9 (MD5) / Approved for entry into archive by Simone de Andrade Lopes Pires (simone.lopes@fgv.br) on 2018-09-04T19:24:19Z (GMT) No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_2018.pdf: 4587968 bytes, checksum: 9f93d7aab79b6eeafed4e925d67c24f9 (MD5) / Approved for entry into archive by Suzane Guimarães (suzane.guimaraes@fgv.br) on 2018-09-05T13:01:10Z (GMT) No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_2018.pdf: 4587968 bytes, checksum: 9f93d7aab79b6eeafed4e925d67c24f9 (MD5) / Made available in DSpace on 2018-09-05T13:01:10Z (GMT). No. of bitstreams: 1 State-Of-The-Art Practices Being Reported by the PRME Champions Group - A Reference to Advance Education for Sustainable Development_2018.pdf: 4587968 bytes, checksum: 9f93d7aab79b6eeafed4e925d67c24f9 (MD5) Previous issue date: 2018-05-28 / This study aims to offer a diagnostic of the 'state-of-the-art' practices being reported throughout the Sharing Information Process (SIP) by the Champions Group, a group of schools that are signatories of the Principles of Responsible Management Education (PRME, a United Nations Global Compact initiative), committed to spearheading transformational change toward more socially and environmentally responsible leadership. The study also suggests an analytical model - based on qualitative research and documentary analysis – to define the study sample, investigate data, identify patterns, organise and codify a large amount of information within all reports searched. The analytical model represents a framework in which the result is a collection of practices being reported, functioning as a useful guide and practical reference for higher educational institutions – signatory or otherwise – when promoting or advancing transformational change in their business model. The framework could also be valuable for Graduate Schools – or even Primary Schools to High Schools – considering the urgency of the 2030 Agenda, especially its 4.7 target, referred to as 'An education for sustainable development and global citizenship'. / Este estudo propõe um diagnóstico do que seria o estado da arte das práticas sendo reportadas através dos relatórios SIP (Sharing Information Process) pelo Champions Group, um grupo de escolas de negócios que são signatárias do Principles of Responsible Management Education (PRME, uma iniciativa da Organização das Nações Unidas pelo Pacto Globa) e que se comprometeram a liderar mudanças transformacionais em direção a formação de lideranças mais responsáveis quanto a aspectos sociais e ambientais. O estudo também sugere um modelo analítico – baseado em pesquisa qualitativa a análise documental – para os processos de definição da amostra de pesquisa, de investigação de informações, identificação de padrões, organização e codificação de uma vasta quantidade de dados contidos no total de relatórios pesquisados. O modelo analítico representa um framework no qual o resultado corresponde a compilação das práticas reportadas, representando um guia útil e uma referência prática para instituições de ensino superior – signatárias ou não do PRME – quando estiverem promovendo ou avançando em mudanças transformacionais de seu modelo de negócio. O framework pode também ter valor para escolas de Graduação – ou mesmo para escolas de ensino fundamental e ensino médio – considerando a urgência destacada na Agenda 2030, especialmente na meta 4.7, que faz referência a 'uma educação para o desenvolvimento sustentável e para a cidadania global'.
253

Hartbeespoortdam Butterfly Conservancy : an ecological splurge

Pettey, Ryan Patrick 28 May 2004 (has links)
The thesis focuses on different habitable spaces which have been designed to promote the existence of a number of South African butterfly species. The architecture responses to the context as well as to one of the largest insect groups, the order L e p i d o p t e r a. Following a sustainable approach, more ecological knowledge is at the core of the design. Instead of human functional needs driving the design, site components respond to the indigenous spatial character, climate, topography, soils, and vegetation as well as compatibility with the existing cultural context. / Dissertation (MArch(Prof))--University of Pretoria, 2006. / Architecture / unrestricted
254

The evaluation of environmental reporting by publicly listed South African banks / Evaluation of environmental reporting by listed South African banks

Oduro-Kwateng, George January 2010 (has links)
Recently, bankers have come to realise that banking operations, especially corporate lending, affect and are affected by the natural environment and that consequently, the banks might have an important role to play in helping to raise environmental standards. Although the environment presents significant risks to banks, in particular environmental credit risk, it also perhaps presents profitable opportunities. Stricter environmental regulations have forced companies to invest in environmentally friendly technologies and pollution control measures and in tum generated lending opportunities for bankers. This research examines the corporate practices of three of the four dominant banks in South Africa with respect to the environment, focusing on issues of climate change and environmental risk management by way of reporting and disclosure to all stakeholders. The emphasis on environmental reporting by South African banks has been reinforced by the latest release of the King III Report on Corporate Governance in South Africa. Global governance requires that the triple-bottom line should be applied in all corporate undertakings due to globalisation and trade liberalisation; however, the banking sector has responded poorly to the clarion call. The false view that the banks have no significant relationship with environmental degradation is being disproved. Environmental management is a huge and massive reconstruction of what has gone wrong with nature by human influence. The South African banks have had to face with the challenging tasks of reporting on the direct and mostly the indirect impacts of their environmental activities. Based on the three sampled banks which incidentally had greater percentages of the market capitalizations, the banks have fairly performed in environmental reporting. For example, Standard Bank (SA) Ltd has just signed the Equator Principles in 2007 implying corporate lending was done in 2007 without any respect to environmental impact assessments by corporate borrowers. Consequently, environmental reporting was not done to facilitate informed decision-making by stakeholders mostly shareholders and the communities where borrowers tun businesses. The objective of this research study is to investigate the extent and quantity of/voluntary environmental disclosures in the annual and sustainability reports of the banks listed on Johannesburg Stock Exchange. The periods examined were those subsequent to the release of the Exposure Draft Coalition for Environmentally Responsible Economies (CERES) Global Reporting Initiatives (GRI) issued in 1999. Using content analysis to focus on the environmental aspects, the research study compared three annual reports and three sustainability reports of 2007 year for the three sampled banks in order to evaluate reporting practices in the period surrounding this intervention. The results suggest a trend to triple bottom-line reporting and the extent and quantity of environmental information, albeit in specific categories.
255

Produto interno bruto ajustado ambientalmente para Amazônia legal brasileira: uma análise de matriz de insumo-produto e matriz de contabilidade social / Environmental gross domestic product for Brazilian Legal Amazon: an analysis of input-output matrix and social accounting matrix.

Andrea Castelo Branco Brasileiro 13 November 2012 (has links)
The purpose of this work was to present and apply an analytical tool to the flows of goods and income between economic agents and the environment that allows us to calculate the Environmental Gross Domestic Product (EGDP) for Brazilian Legal Amazon. In order to achieve this goal the Environmental Social Accounting Matrix (ESAM) was developed. The model was developed from the traditional Social Accounting Matrix, the Environmental Input-Output Analysis Models, and from the United Nations handbook on the System of Integrated Environmental and Economic Accountings. The EGDP was calculated from the Environmental Input-Output Analysis, since the unavailability of data did not allow the application of the model of ESAM. The flows between the economy and the environment considered were the emissions of green house gases (depreciation of natural capital) and the investment needed to return the air to the same quality it had before being polluted. The results showed that the inclusion of depreciation of natural capital in the Gross Domestic Product (GDP) and in the added value (AV) calculation for each industry of the Brazilian Legal Amazon Region diminished the AV significantly in the industries of cattle (235%), soybean (77%), and other activities of livestock and agricultural (24%). In the Rest of Brazil, the industries with the highest impact of depreciation of natural capital on AV were soybean (30%), cattle (15%) and sugarcane (13%). The total EGDP of the Brazilian Legal Amazon Region was 15% smaller than its total GDP, whereas this difference for the rest of Brazil was 1%. Considering that the GDP is a component of economic wellbeing, the results show a significant reduction in economic wellbeing due to green house gas emissions released into the air by economic activities, mainly due to land use changes. The Environmental Social Accounting Matrix Model is a useful tool to help decision makers since it offers an analytical instrument for economic behavior and the impacts of economic activities on the environment. / The purpose of this work was to present and apply an analytical tool to the flows of goods and income between economic agents and the environment that allows us to calculate the Environmental Gross Domestic Product (EGDP) for Brazilian Legal Amazon. In order to achieve this goal the Environmental Social Accounting Matrix (ESAM) was developed. The model was developed from the traditional Social Accounting Matrix, the Environmental Input-Output Analysis Models, and from the United Nations handbook on the System of Integrated Environmental and Economic Accountings. The EGDP was calculated from the Environmental Input-Output Analysis, since the unavailability of data did not allow the application of the model of ESAM. The flows between the economy and the environment considered were the emissions of green house gases (depreciation of natural capital) and the investment needed to return the air to the same quality it had before being polluted. The results showed that the inclusion of depreciation of natural capital in the Gross Domestic Product (GDP) and in the added value (AV) calculation for each industry of the Brazilian Legal Amazon Region diminished the AV significantly in the industries of cattle (235%), soybean (77%), and other activities of livestock and agricultural (24%). In the Rest of Brazil, the industries with the highest impact of depreciation of natural capital on AV were soybean (30%), cattle (15%) and sugarcane (13%). The total EGDP of the Brazilian Legal Amazon Region was 15% smaller than its total GDP, whereas this difference for the rest of Brazil was 1%. Considering that the GDP is a component of economic wellbeing, the results show a significant reduction in economic wellbeing due to green house gas emissions released into the air by economic activities, mainly due to land use changes. The Environmental Social Accounting Matrix Model is a useful tool to help decision makers since it offers an analytical instrument for economic behavior and the impacts of economic activities on the environment.
256

Srovnání vlivu tvaru konvergentní a Lavalovy dýzy v clonkách detektoru na výsledný tlak na dráze sekundárních elektronů pomocí systému CAE / Using Computer Aided Engineering for analyse the detector

Vyroubal, Petr January 2011 (has links)
This master's thesis deals with influence of the shape comparison of convergent and Laval nozzles in the secondary electron detector shutters to the resulting pressure and gas flow in the secondary electron detector for environmental scaning electron mictoscope. To the detector analysis are used Computer Aided Engineering systems CAD and CAE, SolidWorks and SolidWorks Flow Simulation.
257

Elastomerní plniva jako potencální surovina pro betony a malty / Elastomer fillers as a potential raw material for concrete and mortar products

Jankech, Filip January 2017 (has links)
To attain a sustainable development in the field of building materials, it is necessary to consider environmental, economic, and social aspects of the industrial production. This thesis addresses the first two aspects. Both theoretical and practical research were implemented in order to study the possibility to replace the commonly used RDPs, that are being used in the dry-mix mortar industry as a primary additive, with the industrially processed elastomer waste materials, such as recycled tire rubber. The review of the scientific literature processed within the theoretical research discloses the state of the art in the field of polymer modification of the mortar products and the effect of the commonly used modifiers and elastomer fillers on the performance of mortar and concrete products. The experimental research was implemented to study the possibility of the replacement of the RDPs for the elastomer fillers. The performance of fresh and hardened mortar containing various amounts of elastomer particles was studied. The results indicate, that the partial replacement could be feasible without worsening the performance of the product.
258

Wasting our future by wasting the Sea : How to combat marine pollution from land-based sources on international and regional level

Fransson, Lovisa January 2020 (has links)
In the United Nations Convention on the Law of the Sea, the environmental protection of the marine environment was first addressed in a comprehensive manner on an international level. However, the Convention distinguishes between four different sorts of pollution depending on which source the pollution originates from. Still, one of these sources play a more crucial role in the protection of the marine environment than the other since that source is estimated to stand for 80 percent of all the marine pollution; namely marine pollution from land-based sources. As the throw-away culture has led to products being disposed of at a faster rate than ever before, in particular plastic products, the amount of land-based debris has also substantially increased over the last decades. This increased disposal rate of products in combination with poor waste treatment has consequently led to many kinds of wastes ending up in the ocean and causing severe harm, not only to the marine environment and its living species, but also to humans that eat the fish and use the many other ecosystem services of the Sea. In this thesis, some prominent international conventions on marine pollution from land-based sources are examined; namely the United Nations Convention on the Law of the Sea, the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, as well as the Stockholm Convention on Persistent Organic Pollutants. To achieve United Nations Sustainable Development Goal number 14.1 to significantly reduce marine pollution from land-based sources by 2025, this thesis claims that international laws addressing this sort of pollution need to be implemented. Moreover, this thesis rests on the belief that regional implementation is a crucial component in making states align with international law. However, while regional implementation has been ambitious in the European Union Law, many regions still lack enforceable frameworks that aim to reduce and prevent marine pollution from land-based sources.
259

More Than Skin Deep : An Investigation of Consumer Behavior Toward Green Skincare Products in the European Context

Szalaiova, Dana, Vidrinskas, Mark January 2023 (has links)
This bachelor’s thesis is a quantitative study examining the factors influencing the Green Purchase Intention of (green) skincare among European consumers. The underpinning theory for this paper was the Theory of Planned Behavior and its influencing constructs such as Attitude, Subjective Norm, and Perceived Behavioral Control, as well as various selected determinants such as Environmental Concern, Environmental Knowledge, Health Concern, Injunctive Norm, Descriptive Norm, Electronic Word-of-Mouth, Price Sensitivity, Availability, and Perceived Consumer Effectiveness. The determinants were selected after conducting a literature review that primarily consisted of secondary data in the form of research articles dealing with the same research area of Green Purchase Intention. In order to collect primary data relevant to this study, an online survey in the form of a questionnaire was employed. Overall, 385 respondents from various European countries took part in this study. The survey sample was statistically tested using the SPSS AMOS and SPSS software. This was done in order to utilize the data collected fully. Therefore, two hypothesis models were constructed for this study. The results of Model 1, which were tested using SPSS AMOS denoted that Attitude had a significant relationship with Green Purchase Intention of green skincare products. The results of Model 2, which were tested using SPSS showed that Environmental Concern, Environmental Knowledge, Health Concern, and Perceived Consumer Effectiveness had a significant positive relationship with Green Purchase Intention. Thus, as a result, this study offers findings that manufacturers and retailers of green skincare could use to advance their marketing strategies. Primarily, it can be argued that green skincare brands should focus on targeting consumers who are already environmentally conscious rather than trying to gain over consumers with no environmental knowledge and concern. However, we do not deem our results sufficient enough to allow us to provide further managerial contributions.
260

Desarrollo y optimización de wood plastic composites con matriz biopolimérica y fibras naturales

Dolçà Camáñez, Celia 02 September 2022 (has links)
Tesis por compendio / [ES] Debido a la preocupación por la contaminación derivada del uso de los plásticos y la gran cantidad de residuos generados a nivel mundial, se desarrollaron diferentes compuestos plásticos reforzados con fibras naturales respetuosos con el medio ambiente (WPC) para su caracterización y optimización. En primer lugar, se utilizó polietileno de alta densidad de base biológica (BioHDPE) como matriz polimérica y diferentes fibras cortas naturales como el cáñamo, el lino y el yute. Se mezclaron mediante extrusión de doble husillo y se moldearon en piezas mediante moldeo por inyección, se añadió un copolímero de injerto de etileno con anhídrido maleico (PE-g-MA) a dos partes por cien de resina al WPC durante el proceso de extrusión para reducir la falta de compatibilidad entre las fibras lignocelulósicas y la matriz polimérica. Como resultado, se observó en el análisis térmico, una ligera mejora de la estabilidad térmica de los compuestos reforzados con las tres fibras, aumentado la temperatura de fusión y de degradación del compuesto. Además, también aumentó la absorción de agua de los compuestos. Se obtuvo, especialmente, un aumento drástico del módulo de Young y de la resistencia al impacto de los compuestos con refuerzo de fibra de cáñamo. Debido a estos resultados, a continuación, se realizó un estudio con la misma matriz polimérica (BioHDPE) y diferentes porcentajes (2,5 a 40,0% en peso) de fibras cortas de cáñamo (HF) como refuerzo natural, utilizando la misma técnica por fusión y extrusión de doble husillo del compuesto que se moldeo por inyección. También se utilizó como agente compatibilizante, el copolímero maleinizado, de injerto de etileno con anhídrido maleico (PE-g-MA) para mejorar la escasa compatibilidad entre la matriz de BioHDPE altamente no polar y las fibras lignocelulósicas altamente hidrofílicas. El 40% en peso de fibra dio como resultado un aumento importante del módulo de Young y la resistencia al impacto del BioHDPE, obteniendo valores de 5275 MPa y 3,6 kJ/m2, respectivamente, en comparación con el bioHDPE puro de 826 MPa y 2,0 kJ/m2. En cuanto al cambio de color de las muestras inyectadas, se observó que el aumento de fibra generó una clara modificación en las tonalidades finales de las piezas, alcanzando colores muy similares a las maderas oscuras para porcentajes superiores al 20%.Finalmente, se desarrollaron nuevos composites de alto rendimiento mediomabiental utilizando un 30% de fibra corta de cáñamo y como matriz polimérica copolímero de polibutilén succinato-co-adipato paracialmente de origen renovable (BioPBSA). En este caso, para mejorar la interacción entre la fibra y la matriz no solo se empleó el injerto copolímero de PBSA injertado con anhídrido maleico (PBSA-g-MA), sino que se utilizaron diferentes aditivos por extrusión reactiva al composite como aditivos derivados del ácido itacónico de base biológica, como el dibutil itaconato (DBI) y un copolímero de PBSA injertado con ácido itacónico (PBSA-g-IA). La introducción de fibras de cáñamo, dieron como resultado una mejora en la rigidez del polímero base, el módulo de tracción del BioPBSA puro 281 MPa aumentó considerablemente alcanzando valores de 3482 MPa. Los compuestos con DBI obtuvieron una mejora en la ductilidad y una disminución en las propiedades de tracción, en contraste con las muestras compatibles con copolímeros que mejoraron la resistencia a la tracción. / [CA] Degut a la preocupació per la contaminació derivada de l'us dels plàstics i la gran quantitat de residus generats a nivell mundial, es desenvoluparen diferents compostos reforçats amb fibres naturals respectuoses amb el medi ambient (WPC) per a la seva caracterització i optimització. En primer lloc, es va utilitzar polietilè d'alta densitat de base biològica (BioHDPE) com a matriu polimèrica i diferents fibres curtes naturals com el cànem, el lli i jute. Es van fondre mitjançant extrusió de doble tornavís i es moldejaren en peces mitjançant moldejat per injecció, es va afegir un copolímer d'empelt d'etlé i anhídrid maleic (PE-g-MA) a dues parts per cent de resina al WPC durant el procés d'extrusió per a reduir la falta de compatibilitat entre les fibres lignocel·lulòsiques i la matriu polimèrica. Com a resultat, es va observar en l'anàlisis tèrmica, una lleugera millora de l'estabilitat tèrmica dels compostos reforçats amb les tres fibres , augmentant la temperatura de fusió i de degradació dels compostos. Es va obtenir, especialment, un augment dràstic del mòdul de Young i de la resistència a l'impacte dels compostos amb reforç de fibra de cànem. Degut a aquestos resultats, a continuació es va realitzar un estudi amb la mateixa matriu polimèrica (BioHDPE) i diferents percentatges (2,5 a 40,0% en pes) de fibra curta de cànem (HF) com a reforç natural, utilitzant la mateixa tècnica per fusió i extrusió de doble tornavís del compost que es va moldejar per injecció. També es va utilitzar com agent compatibilitzant, el copolímer meleinitzat, anhídrid maleic d'empelt de polietilè (PE-g-MA) per millorar l'escassa compatibilitat entre la matriu de BioHDPE altament no polar i les fibres lignocel·lulòsiques altament hidrofíliques. El 40% en pes de fibra va donar com a resultat un augment important del mòdul de Young i la resistència a l'impacte del BioHDPE, obtenint valors de 5275 MPa i 3,6 kJ/m2, respectivament, en comparació amb el bioHDPE pur de 826 MPa i 2,0 kJ/m2. En quant al canvi de color de les mostres injectades, es va observar que l'augment de fibra va generar una clara modificació en les tonalitats finals de les peces, aconseguint colors molt similars a les fustes fosques per a percentatges superiors al 20%.Finalment, es van desenvolupar nous composites d'alt rendiment medioambiental utilitzant un 30% de fibra curta de cànem i com a matriu polimèrica copolímer de polibutilèn succinat-co-adipat paracialment d'origen renovable (BioPBSA). En aquest cas, per millorar la interacció entre la fibra i la matriu no només es va emprar l'empelt copolímer de PBSA empeltat amb anhídrid maleic (PBSA-g-MA), sinó que es van utilitzar diferents additius per extrusió reactiva al composite com a additius derivats de l'àcid itacònic de base biològica, com el dibutil itaconat (DBI) i un copolímer de PBSA empeltat amb àcid itacònic (PBSA-g-IA). La introducció de fibres de cànem, van donar com a resultat una millora en la rigidesa del polímer base, el mòdul de tracció del BioPBSA pur 281 MPa va augmentar considerablement aconseguint valors de 3482 MPa. Els compostos amb DBI van obtenir una millora en la ductilitat i una disminució en les propietats de tracció, en contrast amb les mostres compatibles amb copolímers que van millorar la resistència a la tracció. / [EN] Due to the concern about the pollution derived from the use of plastics and the large amount of waste generated worldwide, different environmentally friendly natural fiber reinforced plastic compounds (WPC) were developed for their characterization and optimization. First, bio-based high-density polyethylene (BioHDPE) was used as the polymer matrix and different natural short fibers such as hemp, flax and jute. They were fused by twin screw extrusion and molded into pieces by injection molding. Polyethylene graft maleic anhydride (PE-g-MA) was added at two parts per hundred resin to the WPC during the extrusion process to reduce the lack of compatibility between the lignocellulosic fibers and the polymeric matrix. As a result, a slight improvement in the thermal stability of the composites reinforced with the three fibers was observed in the thermal analysis, increasing the melting temperature and degradation of the composite. In addition, it also increased the water absorption of the compounds. In particular, a drastic increase in the Young's modulus and the impact resistance of the hemp fiber reinforced composites was obtained. Due to these results, a study was then carried out with the same polymeric matrix (bioHDPE) and different percentages (2,5 to 40,0% by weight) of short hemp fibers (HF) as natural reinforcement, using the same technique by melt compunding and extrusion with a twin screw extruder, followed by injection moulding. The maleinized copolymer, polyethylene graft maleic anhydride (PE-g-MA) was also used as a compatibilizing agent to improve the poor compatibility between the highly non-polar BioHDPE matrix and the highly hydrophilic lignocellulosic fibers. The 40 wt% fiber resulted in a significant increase in Young's modulus and impact strength of BioHDPE, obtaining values of 5275 MPa and 3.6 kJ/m2, respectively, compared to pure bioHDPE of 826 MPa and 826 MPa. 2.0kJ/m2. Regarding the color change of the injected samples, it was observed that the increase in fiber generated a clear change in the final shades of the pieces, reaching colors very similar to dark wood for percentages greater than 20%.Finally, new green composites were developed using 30% short hemp fiber and a partically biobased polybutylene succinate-co-adipate copolymer (BioPBSA) as polymeric matrix. In this case, to improve the interaction between the fiber and the matrix, not only was the PBSA graft copolymer grafted with maleic anhydride (PBSA-g-MA) used, but different additives were used by reactive extrusion to the composite as additives derived from the Bio-based itaconic acid, such as dibutyl itaconate (DBI) and a copolymer of PBSA grafted with itaconic acid (PBSA-g-IA). The introduction of hemp fibers resulted in an improvement in the stiffness of the base polymer, the tensile modulus of pure BioPBSA 281 MPa increased considerably, reaching values of 3482 MPa. Composites with DBI obtained an improvement in ductility and a decrease in tensile properties, in contrast to samples compatible with copolymers that improved tensile strength. / Agradecer al Fondo Europeo de Desarrollo Regional (FEDER) de la Unión Europea por cofinanciar el proyecto “NABITEX—Textiles técnicos innovadores basados en fibras naturales SUDOE para ser aplicados en el Sector del Hábitat” a través del Programa SUDOE de Interreg (SOE2/P1/ P0524). / Dolçà Camáñez, C. (2022). Desarrollo y optimización de wood plastic composites con matriz biopolimérica y fibras naturales [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185679 / Compendio

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