Abstract: The interface between glass fiber and epoxy resin is the key to improve the properties of composites. In this experiment, the amic acid emulsion (SA-1) was synthesized, and the polyvinylpyrrolidone(PVP) was added to the emulsion to Compound SA-2. The surface of glass fiber was modified by the SA-1 and SA-2 amic acid emulsion in order to have a good interfacial adhesion with epoxy resin. The emulsion particle size were characterized by the Nano-particle size analyzer, transmission electron microscopy (TEM) and the sizing components of the functional group was tested by Fourier transform infrared spectroscopy (FT-IR). The effect of sizing treatment on the surface morphology of glass fiber was studied by scanning electron microscope (SEM) and atomic force microscope (AFM), and the tensile properties of single fibers and interface shear properties of composites (IFSS) were measured by monofilament stretch and micro-sticky method, respectively. The results showed that the average particle size of SA-2 emulsion was 99 nm and the distribution range was 21 nm~200 nm, which was better than the SA-1. The film layer of SA-1 emulsion sizing agent was smooth with an average thickness of 0.20 μm, and after the SA-2 sizing, the surface roughness of the glass fiber was increased and the thickness of the film layer was 0.12 μm. The tensile properties of the monofilament decreased from 1.401 GPa to 1.369 GPa, and the IFSS of the composite increased from 20.06 MPa to 26.84 MPa after SA-1 sizing. The IFSS of the composite after sizing treatment of SA-2 was 32.70 MPa, which was increased by 63.01%, while the tensile properties of the monofilament decreased to 1.383 GPa.

Key words: glass fiber, epoxy resin, surface modification, amic acid