Polymer materials can be divided into rubber, fiber, plastic, polymer adhesive, polymer coating and polymer based composite materials according to their characteristics.
① Rubber is a type of linear flexible polymer. Its molecular chains have low secondary valence and good flexibility, and can undergo significant deformation under external forces. After removing external forces, it can quickly recover to its original state. There are two types of rubber: natural rubber and synthetic rubber.
② Fibers are divided into natural fibers and chemical fibers. The former refers to silk, cotton, hemp, wool, etc. The latter is made from natural or synthetic polymers through spinning and post-processing. Fibers have high secondary force, low deformation ability, and high modulus, and are generally crystalline polymers.
③ Plastics are mainly composed of synthetic resins or chemically modified natural polymers, followed by the addition of fillers, plasticizers, and other additives. Its intermolecular covalent force, modulus, and deformation are between rubber and fiber. Usually classified into thermosetting plastics and thermoplastic plastics based on the characteristics of synthetic resins; It is further divided into general plastics and engineering plastics according to their purpose.
④ High molecular adhesive is a kind of adhesive material which is mainly made of synthetic natural high molecular compound. There are two types of adhesives: natural and synthetic. Synthetic adhesives are widely used.
⑤ Polymer coatings are made by using polymers as the main film-forming material, adding solvents and various additives. According to different film-forming substances, it can be divided into oil coatings, natural resin coatings, and synthetic resin coatings.
⑥ Polymer based composite materials are a type of composite material made from polymer compounds as the matrix and various reinforcing materials added. It integrates the performance characteristics of existing materials and can be designed according to needs. Polymer composite materials, also known as polymer modification, are divided into molecular modification and blend modification.
⑦ Functional polymer materials. Functional polymer materials not only have the general mechanical properties, insulation properties, and thermal properties of polymers, but also have special functions such as material, energy, and information conversion, magnetism, transmission, and storage. Practical materials include polymer information conversion materials, polymer transparent materials, polymer simulated enzymes, biodegradable polymer materials, polymer shape memory materials, and medical and pharmaceutical polymer materials.
Polymers can be classified into the following categories based on their mechanical properties and usage status. However, there is no strict boundary between various types of polymers. The same polymer can be made into plastic or fiber using different synthesis methods and molding processes, such as nylon. Polymers such as polyurethane have both glassy properties and good elasticity at room temperature, making it difficult to say whether they are rubber or plastic.