ABSTRACT Understanding the magnitude and mechanisms of the soy based polyurethane (PU) foams and properties of materials has implications on the application of this foams. Insulators protect devices from aggressive heat. However, due to the highly porous nature of the foams and the increase in interfaces due to fillers such as kenaf core, helps increase mechanical properties, while maintaining the light density of the foam. The effect of fillers on is a critical parameter in investigating the thermal properties and its effect on biodegradability. In this paper, we use thermal conductivity, compression values, and scanning electron microscopy (SEM) to understand the phenomena behind these results. Additionally a compostability test was performed to determine degradation under standard composting conditions. KEYWORDS: thermal conductivity, MTS, Soy based PU, compostability, SEM