Polypropylene‐based in situ fibrillation‐reinforced ternary composite foams with improved filler‐phase dispersion

Abstract Recently, the issue of energy‐saving and environmental protection has attracted enormous interest in developing polymeric composite foams. Fillers have been identified as major materials to tailor cellular structures and mechanical properties for single component thermoplastics. However, it is often difficult to achieve the desired effect due to the natural tendency of fillers. The study aims to provide a facile method for improving the dispersion and arrangement of filler phase based on in situ fibrillation. Polytetrafluoroethylene (PTFE) was used in the in situ fibrillated phase to promote the dispersion of talc throughout the polypropylene (PP) matrix for the ternary composite foams of PP/talc/PTFE. The mechanisms of PTFE fibrils and their effect were studied in terms of crystallization, rheology, foaming behavior, and mechanical properties. The results proved that a fibrillar network was formed by the PTFE fibrils with high aspect ratios, which had a remarkable effect on melt strength and viscoelasticity, thus improving the cellular structure and impact strength. Moreover, the higher the talc content, the better the effect on these properties with the existence of PTFE fibrils, indicating that the in situ fibrillated phase improved fillers dispersion and enhanced the reinforcing effect of filler phase.