The polymer is typically a nonpolar material that is hydrophobic and oleophilic. As mentioned above, according to the difference in surface polarity of minerals, they can be divided into two major categories: polar minerals that are hydrophilic and oleophobic, and nonpolar minerals that are hydrophobic and oleophilic. In nature, apart from a few minerals such as graphite, diamond, sulfur, molybdenite, coal, talc, which are nonpolar minerals, the vast majority are polar minerals (see the chapter “Surface Wettability and Surface Polarity of Minerals,” Table 2). Due to the difference in the surface properties of the mineral powder and the polymer, that is, the wettability between the two is poor, if the polar mineral powder is directly added to the nonpolar polymer material, it is difficult to distribute uniformly (Fig. 1a), not only to produce defects centered on the agglomerated powder, but also to produce gaps or defects between the two interfaces (Fig. 9-7-3a). There are two solutions: the one is that change the properties of the polymer, that is, changes the material from nonpolar to polar to adapt to the mineral powder; the other is that changes the surface properties of the mineral powder, that is, changes the powder surface from polar to nonpolar to adapt to the polymer. Obviously, the former is not feasible, while the latter is the widely used viable method.