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Valorização da lã de ovelha: desenvolvimento e caracterização de painéis de isolamento térmico
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O setor da construção civil busca continuamente soluções que promovam maior eficiência energética e menor impacto ambiental, tornando o desempenho térmico dos edifícios um requisito fundamental para a sustentabilidade do ambiente construído. Paralelamente, a lã de ovelha proveniente de raças autóctones portuguesas apresenta reduzido interesse para a indústria têxtil devido à elevada espessura das fibras, sendo frequentemente subvalorizada ou descartada como resíduo agropecuário. Neste contexto, a presente dissertação teve como objetivo desenvolver e caracterizar painéis compósitos bio-baseados para isolamento térmico, valorizando este recurso natural através da sua combinação com resina natural de pinheiro. O desenvolvimento experimental foi conduzido de forma iterativa, envolvendo sucessivos ajustes na composição do compósito e nos parâmetros de processamento. Os painéis foram produzidos através da organização ortogonal das fibras de lã em múltiplas camadas, seguida da aplicação do ligante e consolidação por prensagem térmica. Durante a fase de desenvolvimento, foram avaliadas diferentes formulações contendo resina natural de pinheiro, com e sem incorporação de óleo de linhaça, bem como diferentes condições de processamento, até à definição do protocolo de fabrico final. A caracterização térmica foi realizada pelo método da Placa Quente Protegida, utilizando o equipamento λ-Meter EP500e. Os ensaios foram conduzidos às temperaturas médias de 15 °C, 25 °C e 40 °C, permitindo avaliar o comportamento térmico das diferentes formulações desenvolvidas. Os resultados demonstraram que todas as amostras apresentaram valores de condutividade térmica compatíveis com materiais isolantes utilizados na construção civil. Verificou-se ainda que a incorporação de óleo de linhaça, inicialmente adotada para melhorar a trabalhabilidade da resina, comprometeu a cura do material e reduziu a sua estabilidade física. A formulação otimizada, constituída por lã de ovelha e resina natural de pinheiro sem adição de óleo de linhaça, apresentou densidade aparente de 163,6 kg/m³ e condutividade térmica de 0,0458 W/(m·K) a 15 °C, associando desempenho térmico competitivo a adequada integridade estrutural. Os resultados obtidos demonstram a viabilidade técnica preliminar do compósito desenvolvido como alternativa bio-baseada para aplicações de isolamento térmico em edifícios, contribuindo simultaneamente para a valorização da lã de ovelha de baixo valor comercial e para o desenvolvimento de soluções alinhadas com os princípios da economia circular e da construção sustentável.
The construction sector is continuously seeking solutions that promote greater energy efficiency and reduced environmental impact, making the thermal performance of buildings a fundamental requirement for the sustainability of the built environment. At the same time, sheep wool obtained from native Portuguese breeds has limited interest for the textile industry due to its coarse fiber diameter and is often undervalued or discarded as an agricultural by-product. In this context, the aim of this dissertation was to develop and characterize bio-based composite panels for thermal insulation, valorizing this natural resource through its combination with natural pine resin. The experimental development was conducted through an iterative approach involving successive adjustments to the composite formulation and processing parameters. The panels were manufactured by arranging sheep wool fibers in orthogonal layers, followed by the application of the binder and consolidation through thermal pressing. During the development phase, different formulations containing natural pine resin, with and without the incorporation of linseed oil, as well as different processing conditions, were evaluated until the final manufacturing protocol was established. Thermal characterization was carried out using the Guarded Hot Plate method with a λ-Meter EP500e apparatus. Tests were performed at mean temperatures of 15 °C, 25 °C, and 40 °C, allowing the thermal behavior of the different formulations to be assessed. The results demonstrated that all developed samples exhibited thermal conductivity values compatible with insulation materials commonly used in the construction industry. It was also observed that the incorporation of linseed oil, initially adopted to improve resin workability, impaired the curing process and reduced the physical stability of the material. The optimized formulation, consisting of sheep wool and natural pine resin without the addition of linseed oil, exhibited an apparent density of 163.6 kg/m³ and a thermal conductivity of 0.0458 W/(m·K) at 15 °C, combining competitive thermal performance with adequate structural integrity. The results demonstrate the preliminary technical feasibility of the developed composite as a bio-based alternative for thermal insulation applications in buildings, while simultaneously contributing to the valorization of low-value sheep wool and the development of solutions aligned with the principles of the circular economy and sustainable construction.
The construction sector is continuously seeking solutions that promote greater energy efficiency and reduced environmental impact, making the thermal performance of buildings a fundamental requirement for the sustainability of the built environment. At the same time, sheep wool obtained from native Portuguese breeds has limited interest for the textile industry due to its coarse fiber diameter and is often undervalued or discarded as an agricultural by-product. In this context, the aim of this dissertation was to develop and characterize bio-based composite panels for thermal insulation, valorizing this natural resource through its combination with natural pine resin. The experimental development was conducted through an iterative approach involving successive adjustments to the composite formulation and processing parameters. The panels were manufactured by arranging sheep wool fibers in orthogonal layers, followed by the application of the binder and consolidation through thermal pressing. During the development phase, different formulations containing natural pine resin, with and without the incorporation of linseed oil, as well as different processing conditions, were evaluated until the final manufacturing protocol was established. Thermal characterization was carried out using the Guarded Hot Plate method with a λ-Meter EP500e apparatus. Tests were performed at mean temperatures of 15 °C, 25 °C, and 40 °C, allowing the thermal behavior of the different formulations to be assessed. The results demonstrated that all developed samples exhibited thermal conductivity values compatible with insulation materials commonly used in the construction industry. It was also observed that the incorporation of linseed oil, initially adopted to improve resin workability, impaired the curing process and reduced the physical stability of the material. The optimized formulation, consisting of sheep wool and natural pine resin without the addition of linseed oil, exhibited an apparent density of 163.6 kg/m³ and a thermal conductivity of 0.0458 W/(m·K) at 15 °C, combining competitive thermal performance with adequate structural integrity. The results demonstrate the preliminary technical feasibility of the developed composite as a bio-based alternative for thermal insulation applications in buildings, while simultaneously contributing to the valorization of low-value sheep wool and the development of solutions aligned with the principles of the circular economy and sustainable construction.
Descrição
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
Palavras-chave
Lã de ovelha Isolamento térmico Painéis compósitos Materiais bio-baseados Construção sustentável Economia circular