Silicone/fluorine‐functionalized flow modifier with low surface energy for improving interfaces in highly filled composites

Highly filled composites have received the urgent demands in various areas (i.e., electrical and thermal conductive materials) due to their many advantages (i.e., low cost and high comprehensive performance). However, it is challenging to simultaneously improve the processability and toughness of highly filled composites by adding a small amount of flow modifier. In this work, for the first time, a novel silicone/fluorine‐functionalized flow modifier (Si-DPF) with low surface energy is synthesized and incorporated into a highly filled magnesium hydroxide/linear low-density polyethylene (MH/LLDPE) composite (80:20 by weight) to simultaneously improve the processability, toughness and flame retardancy. The results show that Si-DPF is dominantly located at the interface between the MH particles and LLDPE matrix to form a core-shell structure, leading to the relatively homogeneous dispersion of the MH particles. The melt equilibrium torque of the MH/LLDPE composite is decreased by 48.9%, the notched impact strength is increased by more than 4 times, and the area under the stress-strain curves is increased by more than 9 times at 5 wt% loading of Si-DPF. Additionally, the corresponding limited oxygen index (LOI) value is increased to 63.8%. This work provides a facile and effective strategy to simultaneously enhance the processability, toughness and flame retardancy of highly filled polymer-based composites by only one kind of multi-functional flow modifier. [Display omitted]