Design of Janus particles based on silica@polystyrene and their compatibilization on poly(p-dioxanone)/poly(lactic acid) composites

The compatibility of poly(p-dioxanone) (PPDO) and poly(lactic acid) (PLA) is very important when they are blended. Herein, three kinds of snowman-like Janus particles (JPs) with different hydrophilic-lipophilic balance (HLB) were prepared by one-pot method by adjusting the surficial functional groups of polystyrene (PS) side and used as the compatibilizer of PPDO/PLA composites. JPs self-assemble at the cell-structure PPDO/PLA interface, which provides channels for the migration of PPDO. The silica (SiO2) side forms hydrogen bond with PLA, and the PS side forms hydrophobic action with PPDO. Therefore, JPs improve interfacial adhesion and suppress phase separation. Among the three JPs, silica@polystyrene-graft-polymethylmethacrylate (SiO2@PS-PMMA) possesses the most excellent interfacial behavior because its HLB value is similar to that of PPDO/PLA composites. Tensile strength was increased from the original 14.59 MPa to the maximum 24.18 MPa at 1.5 phr of SiO2@PS-PMMA JPs, and the elongation at break increased from 39% to 203%.