1. Field
Compositions, composites prepared therefrom, and films and electronic devices including the same are disclosed.
2. Description of the Related Art
A polyimide, which is a high performance polymer, includes a cyclic imide and an aromatic ring in a main chain. As polyimides have relatively superior thermal stability, mechanical properties, and optical properties, they are attractive for application in many advanced technology fields such as microelectronics, aviation, and separation technologies. For example, a polyimide may be applied in a transparent substrate (e.g., flexible substrate) or a flexible transparent protective film for various kinds of display devices and electronic devices such as a light emitting diode or a complementary metal oxide semiconductor sensor and the like. Thereby, there is a need to develop a polyimide-based material having improved optical properties such as yellow index and light transmittance, haze, or the like.
The polyimide-based material may be exposed to a high temperature during a process for a final product such as a display or an electronic device. For example, the production of an organic LED includes treating a substrate at a high temperature of greater than or equal to about 350° C. for a predetermined time in order to maintain primary characteristics of a panel. However, when the transparent polyimide substrate is heat-treated at a high temperature of greater than or equal to the glass transition temperature, the optical properties (light transmittance, haze, and yellow index) of the material may be significantly deteriorated. For example, the high temperature heating treatment may cause a packing phenomenon among chains or in the chain by moving polymer chains. As a result, a charge transfer complex (hereinafter referred to as CTC) may be formed, which is considered as one of the causes of material yellowing since it predominantly absorbs a visible ray of a low wavelength region. In addition, the polyimide substrate may show deteriorated mechanical properties after the heat treatment. Thereby, there is a need to develop a polyimide-based material capable of maintaining the original properties (e.g., mechanical properties and optical properties such as transmittance, yellow index, and the like) even after the high temperature process.
USPTO Backgrounds
USPTO Backgrounds