Hollow Glass Microspheres/Montmorillonite/Epoxy Sheet Molding Compound Composites With Low Density and Excellent Mechanical Properties

Abstract

Epoxy sheet molding compound (ESMC) composites have good mechanical properties, insulation performance, and corrosion resistance, and are widely used in the automotive industry. However, the density of a typical ESMC composite is high, which limits its wider application. Lightweight fillers can reduce the density of ESMC composites, but the addition of lightweight fillers can lead to a decrease in the mechanical properties of the composite. In this paper, we describe our research in which hollow glass microspheres (HGM) were utilized to decrease the density of the ESMC composites. In addition, surface modification of the HGM was performed to enhance the compatibility between the HGM and the epoxy resin (EP), thus improving the mechanical properties. Further, montmorillonite (MMT) was introduced to further improve the mechanical properties of the ESMC composites. The results showed that the density of the prepared composite was about 1.5 g/cm3, which was significantly lower than the industry standard sheet molding compound (SMC) density of 1.9 g/cm3. The flexural strength and impact strength of the resulting ESMC composites containing the modified HGM and an appropriate amount of MMT (EP/SiHGM/MMT-1) reached the maximum value of 80.0 MPa and 28.6 kJ/m2, respectively, which were 39.9 and 51.3% higher than that of the ESMC composite containing only HGM (EP/HGM/MMT-0). On the one hand, the modified HGM was well dispersed in the EP for the chemical bonding effect. On the other hand, the fiber/matrix interface was further improved after introducing an appropriate amount of MMT. Thus, the resulting ESMC composite exhibited low density and excellent mechanical properties and showed great potential for applications that require lightweight and high strength.