Investigation of the effect of rigid polyurethane foam process parameters to microstructure development and foam properties

Nowadays, energy effciency issues are of paramount importance. One of the most widely used and high energy consuming white appliances are refrigerators. Energy efficiency can be achieved by improving the thermal insulation of refrigerators. Polyurethane rigid foamis used in refrigerators as a thermal insulation and support materials. Polyurethane rigid foam, the closed cell structure, inflexible, compact reticulated material and a thermal insulatior of refrigerators. Rigid polyurethane foam is formed by reaction of the polyisocyanate and polyol in the presence of catalyst, surfactants and blowing agents. It is injected to refrigerators doors and body by reaction injection molding machine. The main objectives of this study are to investigate the effects of process parameters on the final foam structure of rigid polyurethane foamsand to establish a relationship between the thermal conductivity and compressive strength properties and microstructure. In the study, an experimental plan was prepared by keeping the 6 Sigma method with determined process parameters. Then rigid polyurethane foams were prepared by using reaction injection molding method. Thermal conductivityand the foam strength were evaluated as outcomes of the study. In addition,the densities, open cell ratio of foams and various measurements on the cells are investigated. Process-structure and structure-property relationships of the results are presented