Desenvolvimento de manta em poliuretano bi-componente à base de óleo de mamona e fibra de miriti para isolamento térmico de telhas metálicas

Abstract

The search for sustainable alternatives to replace commercialized products whose origin comes from non-renewable sources has aroused interest in scientific and technological research into the most varied specimens of natural fibers found in Brazil, including miriti fiber, a plant species typical of the Amazon region and which provides fibrous raw materials for riverside communities. The aim of this research is to develop a composite material from two-component polyurethane (PUR) based on castor oil and reinforced with Miriti fiber (Mauritia flexuosa Mart) to be used as a thermal blanket, given that the incorrect specification, the lack of constructive materials or those that are better adaptable, especially on the roof, have a direct impact on thermal comfort, given that the unique climatic conditions of the Amazon biome, with average annual temperatures above 30º and humidity that can exceed 90%, create a challenging scenario for the development of housing and structures that promote thermal comfort and minimize the need for substantial investments in the maintenance of cooling systems. The state of Pará, especially the equatorial Metropolitan Region of Belém, has rainfall averages of over 300 mm in what is known as the "Amazon winter", which in itself requires roofing systems to be watertight and resistant to the parameters of the environment. In addition, the recent socio-environmental protagonism demanded internationally by local authorities requires a response from the institutions in order to develop technologically viable and environmentally sustainable solutions to the old and new issues faced by Pará society. The aim was also to assess the thermal performance of roof tiles made from different materials, which are often available on the regional market, adopting the normative procedure and on-site measurements of prototypes, according to the criteria defined by NBR 15.575-1 (ABNT, 2013), 15.575-4 (ABNT, 2013) and 15. 575-5 (ABNT, 2013), carried out at the Federal Institute of Education, Science and Technology of Pará, Belém Campus, based on observations of the internal and external temperature of the experimental modules, obtained by sensors, over a period of ninety-two days in the first stage and forty-four days in the second stage, 24 hours a day. Comparisons were also made of the thermal conductivity values calculated using the lee disk method. The results allowed us to conclude that the blanket developed from a bi-component polyurethane based on castor oil, reinforced with miriti fiber, is a promising alternative to replace fibrocement and ceramic tiles. The blanket demonstrated superior thermal performance, providing a significant reduction in thermal conductivity and maintaining lower internal temperatures in the experimental modules compared to the tested tiles.