The application fields of polyisobutylene are closely related to its molecular weight. Generally, low molecular weight and medium molecular weight polyisobutylene can be used as oil additives, tackifiers, sealants, coatings, lubricants, plasticizers, and cable impregnating agents. High molecular weight polyisobutylene can be used as impact modifiers for plastics, raw rubber, and thermoplastic elastomers. After the 1980s, the application of isobutylene polymers in non-lubricating oils continued to expand. For example, in the United States, the consumption in this field accounts for about 1/3 of the total consumption. In Japan, it is about 2/3. The vast majority of polybutene products produced in China are used in lubricating oils. Currently, about 3000 tons of poly(isobutylene) are still imported annually for use as oil additives, producing ashless dispersants, gum bases, tackifiers, sealants, etc. Adding high molecular weight polyisobutylene to natural rubber or styrene-butadiene rubber can improve the aging resistance, weather resistance, flex cracking resistance, ozone resistance, and dielectric properties of rubber at high temperatures, and reduce its water absorption and gas permeability. It can be used for fuel tanks, pipelines, and other containers or linings for various vehicle tires. When added in a small amount of high molecular weight polyisobutylene at 6-10°C above the melting point of plastics, the impact strength, tear strength, tensile-break properties, barrier properties, flexibility, and resistance to acid, alkali, and solvent corrosion of polyolefins can be significantly improved. It can be used for fuel tanks, pipelines, and other containers or linings for various vehicle tires. When added in a small amount of high molecular weight polyisobutylene at 6-10°C above the melting point of plastics, the impact strength, tear strength, tensile-break properties, barrier properties, flexibility, and resistance to acid, alkali, and solvent corrosion of polyolefins can be significantly improved.