Ultra-high thermally and electrically conductive polymer-expanded graphite composites*

Efficient thermal management systems made of polymers are highly desirable due to advantages of polymers such as low weight, cost and corrosion resistance. Inclusion of porous expanded graphite structure into polymer matrix has been examined in this study. We find that expanded graphite leads to excellent thermal and electrical conductivity in polymer composites. Large expansion ratio (~280) of intercalated graphite compound (IGC) results in high volume expanded graphite (EPG). Embedding polyetherimide (PEA) with expanded graphite via solution casting retains the worm structure of expanded graphite in composite, resulting in highly conductive graphite network in polymer. Effective medium theory is further used to compare measurements and predictions.  XPS, XRD and Raman measurements are used to characterize graphene.