The active groups on the surface of EPS particles play a critical role in their compatibility with the polymer matrix.
First, the type of active groups determines the type of interaction. Common active groups such as hydroxyl and carboxyl groups can react chemically with the corresponding functional groups in the polymer matrix, such as forming hydrogen bonds or covalent bonds with amino groups in some polymers. This chemical bonding can greatly enhance the connection strength between EPS particles and polymers, making the two tightly combined and reducing the possibility of interface separation. When the active groups form hydrogen bonds with the polymer matrix, a stable mutually attractive structure is constructed at the molecular level, allowing EPS particles to be evenly dispersed in the polymer matrix instead of agglomerating together.
Second, the number of active groups affects the degree of interaction. When the number of surface active groups is large, more connection points can be generated with the polymer matrix. This is not only conducive to improving compatibility, but also more effectively transmitting stress when subjected to force. For example, when preparing EPS reinforced polymer composites, more active groups mean that EPS particles can better share the externally applied tension or pressure and enhance the overall mechanical properties of the composite. If the number of active groups is small, the bonding force between the particles and the matrix is weak, and interfacial slip is likely to occur when subjected to external forces, resulting in a decrease in material performance.
Furthermore, the uniformity of the distribution of active groups cannot be ignored. If the active groups are evenly distributed on the surface of EPS particles, then when mixed with the polymer matrix, they can interact evenly with the matrix in all directions, making the performance of the entire composite material system more stable and consistent. On the contrary, if the active groups are unevenly distributed, strong or weak bonds may be formed in local areas, which may easily cause stress concentration points and reduce the reliability and durability of the material.
The type, number and uniformity of the active groups on the surface of EPS particles determine the degree and mode of interaction with the polymer matrix at the microscopic level through chemical bonding, physical adsorption and other methods, which in turn has a profound impact on the compatibility of the two, and ultimately affects the comprehensive performance of polymer composites with EPS particles as the filling phase.
