Foamed polymers have added value properties as low density, low thermal conductivity and adaptable mechanical properties as a function of relative density and therefore are extensively used in almost all industrial sectors. Recently, the study of foams based on thermoplastic polyurethane (TPU) is growing in importance mainly because this polymer is one of the most elastic thermoplastics. Many studies have been published on the foaming of different polymers by using the so called gas dissolution foaming process. However, there are very few studies that deal with thermoplastic polyurethanes (TPUs) foams produced by this technique [1-5]. TPU foams due to inherent properties of TPU and the widening of properties provided by foaming could be very interesting materials for several applications. For these reasons, we have focused our research on obtaining synthesized TPUs with different characteristics to produce TPU foams with a wide range of properties.
In this research, TPUs with different contents of hard segment (HS) from 40 to 80 wt% as well as TPUs nanocomposites with different contents of graphene nanoplatelets (GNP) from 0.25 to 1 wt% have been synthesized using the prepolymer method, Synthesized TPUs have been characterized by gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Moreover, extruded samples have been prepared in order to obtain foams by a one-step gas dissolution foaming process. The influence of HS and also GNP contents on the TPU foaming is herein studied analyzing the density and cellular structure of the resulting foams.