Preparation and properties of polymer microspheres filled epoxy composite films by UV-curable polymerization

Interfacial adhesion between fillers and matrix is important to the properties of their composites. In this study, hollow and solid polymer microspheres/epoxy composite films were prepared via powder mixing method and UV-curable polymerization. Interfacial adhesion was established by chemical bonding among the epoxy groups of the microspheres and epoxy matrix . The tensile strength and modulus of polymer microspheres/epoxy composite films first increased and then decreased with increasing the content of fillers. The specific tensile strength and modulus of hollow microspheres/epoxy composites were higher than those of solid microspheres/epoxy composites. The fracture mode of the composite films changed from crack of the polymer microspheres to interfacial debonding with increasing the filler's content . Characteristics of shear yielding deformation, particle bridging and crack bowing mechanisms were identified from the microscopic image of tensile fracture surfaces . The improvement of tensile properties compared with neat epoxy resin was discussed on the basis of percolation mechanism. The hollow polymer microspheres/epoxy syntactic foam films retained high electrical resistivity and UV-shielding property. The UV-curable hollow polymer microspheres/epoxy syntactic foam films with good strength could be used as electrical insulating materials.