Effect of Olefins Grafted Maleic Anhydride on the Compatibility of Polymer Alloys

Forming polymer alloy is an important way to improve the performance of polymer materials, which can effectively improve the performance of materials and overcome their own defects. However, due to the different chemical composition and polarity of different polymer materials, it is often difficult to achieve good compatibility and achieve the expected performance in processing. Therefore, it is very important to introduce the third component compatibilizer.

In this paper, HDPE-g-MAH was blended with PA6 to obtain HDPE-g-MAH/PA6 blends with core-shell structure, and then HDPE was added to get HDPE/HDPE-g-MAH/PA6 blends.

As shown in figure 1, compared with pure HDPE and HDPE/PA6, the impact properties of HDPE/HDPE-g-MA/PA6 blends reached 59.2kJ/m², nearly three times that of pure HDPE, and were significantly higher than that of HDPE/PA6 in the same proportion. Figure 2 is the SEM diagram of the fracture morphology of various components. Through the morphology of the cross section, the obvious core-shell structure is formed in the HDPE/HDPE-g-MAH/PA6 ternary system of 2a-c, which shows that the dispersed phase and the continuous phase show good compatibility. When subjected to external forces, energy can be well transferred between the matrix and the reinforced phase, which is beneficial to improve the properties of the material. Figure 2d and e are binary systems of HDPE/HDPE-g-MAH and HDPE-g-MAH/PA6. It can be seen from the diagram that the system forms an obvious continuous phase, so both HDPE and PA6 can be miscible with HDPE-g-MAH. This is because the HDPE part of HDPE-g-MAH and HDPE can increase their interaction force through molecular chain winding, while PA6 has molecular chain winding. It can also form hydrogen bond and covalent bond with MAH, which greatly improves the interaction force between HDPE-g-MAH and PA6, thus promoting the formation of core-shell structure of HDPE/HDPE-g-MAH/PA6 ternary system and improving the interfacial strength. Fig. 2F is a HDPE/-PA6 binary system without adding HDPE-g-MAH. The obvious gap between the two phases can be clearly seen in the figure, which is due to the difference in polarity between HDPE and PA6, which can not overcome the effect of surface tension. These gaps interrupt the force transfer between the matrix and the reinforcement, and produce defects, so it can be seen that the impact property of HDPE/PA6 is not significantly improved, even lower than that of pure HDPE.

In summary, the addition of the third component compatibilizer can obviously improve the compatibility between different components of polymer alloys and improve the properties of polymer alloys.

                                                      Fig. 1 impact properties of HDPE, HDPE-g-MA and PA6 blends with different components and ratios

Figure 2. The fracture morphology of the HDPE/HDPE-g-MA/PA6 ternary system and several binary system

(a) HDPE/HDPE-g-MA/PA6 80/5/15,(b) HDPE/HDPE-g-MA/PA6 80/10/10

(b) HDPE/HDPE-g-MA/PA6 80/15/5,(d) HDPE/HDPE-g-MA 80/20,

(e) HDPE-g-MA/PA6 25/75,and (f) HDPE/PA6 80/20.