Effect of Polypropylene-Grafted-Maleic Anhydride Content on Physical Properties of Carbon Fiber Reinforced Polypropylene Composites

Carbon fiber reinforced plastics (CFRPs) are widely used in various fields because of their low density and good mechanical properties. Polypropylene (PP) is one of the common matrix materials. However, due to the poor compatibility between PP and CF, the interface performance is affected, and the addition of polypropylene grafted maleic anhydride (PP-g-MAH) as compatibilizer is expected to improve the interface bonding between PP and CF.

In this paper, the mechanical properties of PP-g-MAH composites were studied by preparing PP-g-MAH composites of different proportions. The composition of the fabricated composites is shown in Table 1:

Table 1. Composition of the fabricated composites

Figure 1 is the field emission scanning electron microscope of the fracture of the composite material. It can be seen from the figure that CF is pulled out as a whole in the sample without PP-g-MAH, indicating that the binding force between CF and PP is very weak, and it is difficult to play a strengthening role. When PP-g-MAH is added to the sample, the resin is embedded on the surface of CF, which is beneficial to improve the interface properties of the composites. Therefore, it can be concluded that the addition of PP-g-MAH can significantly improve the interface properties of CF and PP composites.

Figure 2. FE-SEM images of PP/CF/PP-g-MAH composites (a) without PP-g-MAH and incorporated with (b) 5 wt%, (c) 10 wt% and (d) 15 wt% of PP-g-MAH.

Figure 2 shows the izod impact strength of the sample at 23℃ and -30℃.As can be seen from the figure, whether at room temperature or low temperature, the impact strength of the sample added with PP-g-MAH is improved, especially the sample added with 10% PP-g-MAH, which increases the most. This also indicates that PP-g-MAH can effectively improve the interface properties between CF and PP.

Figure 2.Izod impact strength of the fabricated composites measured at −30℃and 23℃