Montagem e teste de dispositivo para determinação do fator K de condutividade térmica em espumas rígidas de poliuretana

Abstract

Rigid polyurethane foams are materials that are used as thermal insulators. They have several applications in various sectors of the industry, being widely used in refrigerated trucks and in refrigerators for domestic, commercial and industrial use. The thermal conductivity of the material is a decisive parameter in the design and dimensioning of the thermal barriers of the equipment. The measurement of thermal conductivity by conventional techniques is not practical in most cases. Therefore, this work aimed to verify the feasibility of determining the thermal conductivity of rigid polyurethane foams for thermal insulation using the hot wire technique. This method offers significant advantages, mainly in terms of simplicity, economy and flexibility over the systems currently used. Two types of foam were analyzed, one type intended for the assembly of refrigerated truck bodies, produced by industrial methods, and another type manufactured and produced in the polymer laboratory of the Federal Technological University of Paraná. The results indicate that the technique is feasible, however, the precision and reproducibility of the measurements are greatly affected by the sample preparation and the electric current in the wire.