Selective distribution of SrTiO₃ in co-continuous composites: An effective method to improve the dielectric and mechanical properties

Tailoring the distribution of functional fillers in co-continuous polymeric matrix is a new approach for fabricating high-performance composites. Herein, the selective distribution of strontium titanate (SrTiO₃, ST) in a co-continuous poly(methyl methacrylate)/chlorinated polyethylene (PMMA/CPE, 70/30) matrix was achieved via altering the mixing sequence and adjusting the wetting coefficient (ω_a). The results showed that the SrTiO₃ distributed in CPE phase was more helpful to improve the dielectric constant and had little influence on the dielectric loss factor. The dispersibility of surface modified SrTiO₃ in PMMA phase was the most uniform and promoted the composite keeping the best mechanical properties among all composites. The selective distribution of SrTiO₃ in co-continuous structure also significantly influenced the rheological properties. The conclusions obtained in this work are beneficial to the manufacture of composites with appropriate dielectric properties and excellent mechanical properties by the selective distribution of inorganic particles in a co-continuous polymeric matrix.