Characteristics and properties of SiO2-Al2O3/EP-PU composite

SiO2-Al2O3/EP-PU nanocomposites, which contained polyurethane (PU) flexible chain, were prepared via epoxy resin, PU and modified silica and alumina particles. Silica and alumina particles were modified by coupling agents KH-560 and KH550, respectively. EP-PU was used as matrix, PU as toughening agent, SiO2-Al2O3 as filled and MTHPA as curing agent. The mass ratio of PU was 30% in this system. The chemical structure of the products was confirmed by FT-IR measurements, the morphological structure of fracture surface and the surface of the hybrid materials were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM), and shearing strength and breakdown field were measured, respectively. When the mass fraction of inorganic component was 10% and the mass ratio of SiO2 to Al2O3 was 4.5:5.5, shearing strength of SiO2-Al2O3/EP-PU was 28.5 MPa and breakdown field was 15 kV/mm, the data could meet the property requirement of insulating material.