Orientation of boron nitride nanosheets in CM/EPDM Co-continuous blends and their thermal conductive properties

The co-continuous blends of chlorinated polyethylene rubber (CM) and ethylene propylene diene rubber (EPDM) were prepared. Boron nitride nanosheets (BNNSs) were filled into the blends and orientated by shearing on a two-roll mill. The microstructure of CM/EPDM blends and the localization of BNNSs were observed by scanning electron microscopy (SEM). The effects of orientation and content of BNNSs based fillers on thermal conductivity and mechanical properties of the composites were investigated. It was found that a co-continuous blend was obtained at the CM/EPDM mass ratio of 1/1, in which the co-continuous structure of the composites and orientation of BNNSS were helpful to improve the thermal conductivity. The CM/EPDM/BNNSs composites had thermal conductivity of 1.65 W/(m·K) (30 wt% BNNSs) and flexibility with elongation at break of 405%. The selective localization in the CM/EPDM co-continuous blends could decrease the percolation threshold to 17wt%. In addition, CM/EPDM/BNNSs composites can reduce the heat build-up during repeated compressing-relaxing compared to CM/BNNSs composites.