Browsing by Author "Larraza, I."
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Item Effect of the biobased polyols chemical structure on high performance thermoset polyurethane properties(2022-12-16) Echeverria-Altuna, O.; Ollo, O.; Larraza, I.; Gabilondo, N.; Harismendy, I.; Eceiza, A.; POLIMEROS; Tecnalia Research & InnovationThe sustainability of the polymeric materials has become a fundamental challenge; therefore, the development of new biobased formulations has gained increasing interest. Thermoset polyurethanes (PURs) present high performance and are a competitive solution for structural composites. However, polyols used in the PUR synthesis are typically from petrochemical origin. Nowdays, a broad range of biobased polyols is available in the market, but there is not yet a specific formulation for high performance PURs composites. The aim of this work was to study the effect of biobased polyols' characteristics in the PUR processing and final properties. In addition, biobased polyol features to synthesize BIO-PURs suitable for structural applications were stablished. The viscosity and reactivity were studied by means of rheology and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied through thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and flexural tests. The results obtained demonstrated the dramatic influence of polyols’ nature on BIO-PUR/PUR properties and their effect on the crosslink density. It was observed that using a high functionality and high hydroxyl index biobased polyol, it was possible to synthesize high performance BIO-PUR suitable for structural composites.Item Occupational exposure to nano-TiO2 in the life cycle steps of new depollutant mortars used in construction(2015-05-26) Vaquero-Moralejo, Celina; Galarza, N.; López de Ipiña, J.M.; Gutierrez-Cañas, C.; Múgica, I.; Aragón, G.; Jaen, M.; Pina, R.; Larraza, I.; Esteban-Cubillo, A.; Thompson, D.; Pui, D.Y.H.; Gelarza, N.; De Ipiña, J. L.López; Tecnalia Research & Innovation; PRINTEX; SMART_MONThe present work is focused on the measurement of workers exposure to nano-TiO2 in the life cycle steps of depollutant mortars. It has been done in the framework of the SCAFFOLD project, which aims at the management of potential risks arising from the use of manufactured nanomaterials in construction. Main findings can be summarized as follows: (1) The occupational exposure to nano- TiO2 is below 0.3 mg/m3 for all measured scenarios. The highest concentrations were measured during the cleaning task (in the nano- TiO2 manufacturing process) and during the application (spraying) of depollutant coatings on a wall. (2) It was found a high release of particles above the background in several tasks as expected due to the nature of the activities performed. The maximum concentration was measured during drilling and during adding powder materials (mean total particle concentration up to 5.591E+04 particles/cm3 and 5.69E+04 particles/cm3). However, considering data on total particle concentration released, no striking differences have been observed when tasks have been performed using conventional materials in the sector (control) and when using materials doped with nano-objects.Item Strategies, methods and tools for managing nanorisks in construction(2015-05-26) López de Ipiña, J.M.; Vaquero-Moralejo, Celina; Boutry, D.; Damlencourt, J.F.; Neofytou, P.; Pilou, M.; Jankowska, E.; Larraza, I.; Pina, R.; Fernández, S.; Contreras, S.; Romero, A.; Calderon, M.; Swiezewsk, P.; Otkallo, K.; Pintea, A.; Salazar, C.; Oroz, T.; Hargreaves, B.; Ciobanu, R.; Tabrea, A.; Hazebrouck, B.; Salvi, O.; Stockmann-Juvala, H.; Vaananen, V.; Pui, D. H. Y.; Thompson, Drew; Tecnalia Research & Innovation; SMART_MON; PRINTEXThis paper presents a general overview of the work carried out by European project SCAFFOLD (GA 280535) during its 30 months of life, with special emphasis on risk management component. The research conducted by SCAFFOLD is focused on the European construction sector and considers 5 types of nanomaterials (TiO2, SiO2, carbon nanofibres, cellulose nanofibers and nanoclays), 6 construction applications (Depollutant mortars, selfcompacting concretes, coatings, self-cleaning coatings, fire resistant panels and insulation materials) and 26 exposure scenarios, including lab, pilot and industrial scales. The document focuses on the structure, content and operation modes of the Risk Management Toolkit developed by the project to facilitate the implementation of "nano-management" in construction companies. The tool deploys and integrated approach OHSAS 18001 - ISO 31000 and is currently being validated on 5 industrial case studies.