As a material that can maintain excellent performance in a high-temperature environment, PET high-temperature tape is widely used in electronics, automobiles, aerospace and other fields. Its performance is mainly dependent on the synergy between the substrate and the adhesive.

Chemical analysis of PET substrates
(1) Chemical structure
The PET substrate is mainly made of polyethylene terephthalate (PET), and its chemical structure is synthesized by terephthalic acid (TPA) and ethylene glycol (EG) through esterification reaction and polycondensation reaction. The presence of benzene rings and ester bonds in the PET molecular chain gives the PET substrate excellent chemical and thermal stability.
(2) Performance characteristics
Thermal stability: PET substrate has a high glass transition temperature and melting temperature, and is able to maintain stable physical and chemical properties at high temperatures.
Chemical resistance: PET substrates are resistant to most organic solvents and chemicals, and are able to maintain stable performance in a variety of chemical environments.
Mechanical properties: PET substrate has high strength and toughness, which can meet the requirements of high-temperature tape for the mechanical properties of the substrate.

(3) Chemical analysis data
Infrared spectroscopy: Infrared spectroscopy is an important means to determine the type of functional groups and their relative content of PET substrates. By infrared spectroscopy, we found that the PET substrate showed a significant carbonyl (C=O) stretching vibration peak at 1715cm^-1, which is the characteristic peak of ester bonds. In addition, the presence of benzene rings in the PET substrate was further confirmed by the expansion and contraction vibration peaks of the benzene ring at 1240 cm^-1 and 1090 cm^-1. These results fully illustrate the chemical structure characteristics of PET substrates.
Nuclear magnetic resonance analysis: Nuclear magnetic resonance analysis is an important method to study the molecular structure of PET substrates. By performing 1H NMR and 13C NMR analysis on PET substrates, we can obtain information about the chemical shifts of hydrogen and carbon atoms. The experimental results show that the hydrogen atoms in the PET substrate mainly appear on the benzene ring (δ=7.2ppm) and the methylene group next to the ester bond (δ=4.1ppm). The chemical shifts of carbon atoms occur in benzene ring (δ=130-140ppm), ester bond (δ=170ppm) and methylene (δ=65ppm), respectively. These results further validate the chemical structure of the PET substrate.
3. Chemical analysis of silicone pressure-sensitive adhesives
(1) Chemical composition
Silicone pressure-sensitive adhesive is mainly made of silicone rubber raw rubber, incompletely miscible silicone resin, crosslinking agent, vulcanizing agent, solvent and other mixtures. Among them, the silicone rubber raw rubber is a continuous phase, which gives the silicone pressure sensitive adhesive the necessary cohesion; Silicone resin is a dispersed phase, which is used as a tackifier to adjust the physical properties of pressure-sensitive adhesives and increase viscosity.

(2) Preparation mechanism
The preparation mechanism of silicone pressure-sensitive adhesive is mainly through physical blending or chemical cross-linking to realize the synthesis between silicone rubber and silicone resin. In the preparation process, adding an appropriate amount of condensation catalyst can promote the connection of some molecules of rubber and resin through the mutual condensation reaction of silanol groups, so as to prevent excessive phase separation after rubber and resin mixing, so as to improve the cohesion of silicone pressure-sensitive adhesive.
(3) Performance characteristics
High temperature resistance: Silicone pressure sensitive adhesive can still maintain stable adhesive performance at high temperature, meeting the requirements of high temperature tape for adhesive.
Chemical resistance: Silicone pressure sensitive adhesives have good resistance to a wide range of chemicals and are able to maintain stable performance in a variety of chemical environments.
Excellent adhesion: Silicone pressure sensitive adhesives have excellent adhesion properties and are able to form a strong bond interface with the adherent.

4. Interaction between PET substrate and silicone pressure-sensitive adhesive
In PET high-temperature tapes, the interaction between the PET substrate and silicone pressure-sensitive adhesive has an important impact on the overall performance of the tape. On the one hand, the chemical and thermal stability of PET substrate provides a basic performance guarantee for the tape. On the other hand, the excellent adhesion properties and high temperature resistance of silicone pressure-sensitive adhesives further improve the overall performance of the tape.
Specifically, the interaction between the PET substrate and the silicone pressure-sensitive adhesive is mainly reflected in the following aspects:
Bonding interface: A strong bonding interface is formed between the PET substrate and the silicone pressure-sensitive adhesive, which makes the tape not easy to fall off or peel off when subjected to external forces.
Thermal stability: Both PET substrate and silicone pressure-sensitive adhesive have high thermal stability, which can maintain stable performance at high temperatures, thereby improving the high temperature resistance of the tape.
Chemical resistance: Both PET substrates and silicone pressure-sensitive adhesives have good resistance to a wide range of chemicals and can maintain stable performance in a variety of chemical environments, thus improving the chemical resistance of the tape.
Chemical analysis of PET substrate and silicone pressure-sensitive adhesive in PET high-temperature tape, their chemical structure, performance characteristics and interactions. PET substrate provides a basic performance guarantee for the tape with its excellent chemical and thermal stability; Silicone pressure-sensitive adhesives, on the other hand, further improve the overall performance of the tape with its excellent adhesion properties and high temperature resistance.