Publicação
Development of bio-based polyurethane aqueous dispersions for industrial applications
| Resumo: | Polyurethanes (PU) are versatile polymers widely used in industrial sectors such as footwear, coatings, and adhesives. However, conventional PU production relies on fossil-based raw materials and organic solvents, raising environmental and health concerns due to the emission of volatile organic compounds (VOCs). In this context, aqueous polyurethane dispersions (PUDs) have emerged as a more sustainable alternative, using water as the primary dispersion medium while retaining the desirable mechanical and chemical properties of polyurethane systems. This dissertation aimed to develop and characterize bio-based aqueous polyurethane dispersions with more than 50% renewable content, targeting applications in the footwear industry. The formulations were prepared using bio-based DIEXTER polyols and synthetic biodegradable polyols (PCL 2000 and PCL 1000) for comparison, through a synthesis process designed to minimize solvent consumption. A total of nine dispersions were produced and characterized in terms of physicochemical, structural, and thermal properties, including pH, solids content, viscosity, particle size, zeta potential, water adsorption–desorption behaviour, film properties such as Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), water vapour permeability, Dynamic Mechanical Analysis (DMA) and adhesive performance through T-peel tests. The synthesized dispersions exhibited pH values near neutrality and solids content within the typical range for stable PUD systems. Biobased formulations exhibited colloidal stability comparable to the synthetic references, with zeta potential values of approximately −48 mV, indicating stable dispersions. The results also revealed differences in particle size and film properties depending on the polyol used. In permeability and adsorption/desorption tests, DTX155_2 exhibited a balanced behaviour comparable to the commercial reference, highlighting its potential for cork agglomerate applications, while DTX274_4 and DTX274_5 showed higher water vapour permeability, making them promising candidates for breathable coating applications. In terms of adhesive performance, the PCL-based systems exhibited higher peel strength, whereas the DTX-based dispersions showed lower adhesion due to the greater rigidity of the resulting films. Overall, the results demonstrate that bio-based polyols are a viable alternative for producing stable aqueous polyurethane dispersions with properties suitable for various applications in the footwear industry. This work contributes to the development of more environmentally friendly materials and highlights the potential of bio-based polyurethane systems within the framework of sustainable materials development. |
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| Autores principais: | Scucato, Julia Gabriela |
| Assunto: | Application for footwear industry Aqueous polyurethane dispersions Bio-based polyol Sustainability |
| Ano: | 2026 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Politécnica de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital da UPB |
| Resumo: | Polyurethanes (PU) are versatile polymers widely used in industrial sectors such as footwear, coatings, and adhesives. However, conventional PU production relies on fossil-based raw materials and organic solvents, raising environmental and health concerns due to the emission of volatile organic compounds (VOCs). In this context, aqueous polyurethane dispersions (PUDs) have emerged as a more sustainable alternative, using water as the primary dispersion medium while retaining the desirable mechanical and chemical properties of polyurethane systems. This dissertation aimed to develop and characterize bio-based aqueous polyurethane dispersions with more than 50% renewable content, targeting applications in the footwear industry. The formulations were prepared using bio-based DIEXTER polyols and synthetic biodegradable polyols (PCL 2000 and PCL 1000) for comparison, through a synthesis process designed to minimize solvent consumption. A total of nine dispersions were produced and characterized in terms of physicochemical, structural, and thermal properties, including pH, solids content, viscosity, particle size, zeta potential, water adsorption–desorption behaviour, film properties such as Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), water vapour permeability, Dynamic Mechanical Analysis (DMA) and adhesive performance through T-peel tests. The synthesized dispersions exhibited pH values near neutrality and solids content within the typical range for stable PUD systems. Biobased formulations exhibited colloidal stability comparable to the synthetic references, with zeta potential values of approximately −48 mV, indicating stable dispersions. The results also revealed differences in particle size and film properties depending on the polyol used. In permeability and adsorption/desorption tests, DTX155_2 exhibited a balanced behaviour comparable to the commercial reference, highlighting its potential for cork agglomerate applications, while DTX274_4 and DTX274_5 showed higher water vapour permeability, making them promising candidates for breathable coating applications. In terms of adhesive performance, the PCL-based systems exhibited higher peel strength, whereas the DTX-based dispersions showed lower adhesion due to the greater rigidity of the resulting films. Overall, the results demonstrate that bio-based polyols are a viable alternative for producing stable aqueous polyurethane dispersions with properties suitable for various applications in the footwear industry. This work contributes to the development of more environmentally friendly materials and highlights the potential of bio-based polyurethane systems within the framework of sustainable materials development. |
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