1. Composition of rubber

Rubber products are made up of raw rubber as the basis and appropriate amount of compounding agent is added.

(1) Raw rubber without additives or natural or synthetic rubber without vulcanization is generally referred to as raw rubber. Natural rubber has good comprehensive properties, but its output can not meet the needs of industry and some special performance requirements, so synthetic rubber is widely used.

(2) In order to improve the properties of rubber products, the additives are called complexes. The compounding agents mainly include vulcanization thorn, filler, vulcanization accelerator, plasticizer, antiaging agent and foaming agent.

(1) Curing agent is similar to curing agent in thermosetting plastics. It makes rubber molecular chains form a cross-link and form a network structure, thus improving the mechanical properties and physical properties of rubber. Sulfur yellow and sulfide are commonly used in Vitex vulcanis.

(2) Fillers are used to improve the mechanical properties of rubber, such as strength, hardness, wear resistance and rigidity. The most commonly used fillers are carbon black and textiles, fibers, and even wire or metal knitted fabrics as skeleton materials. Adding filler can also reduce the amount of raw rubber and reduce the cost of rubber.

(3) The vulcanization of other additives can accelerate the vulcanization process and improve the vulcanization effect; plasticizers are used to increase the plasticity of rubber and improve the moulding process performance; antioxidants are used to prevent or delay the aging of rubber, etc.

2. Characteristics and Application of Rubber Products

Rubber products have the characteristics of high elasticity, high resilience, high strength and high wear resistance. Its modulus of elasticity is very low, only 1-10 MPa, and its elastic deformation is very large, up to 100%-1000%. It has excellent flexibility and energy storage capacity. In addition, it has good wear resistance, sound insulation, damping and insulation. But rubber has poor heat resistance and cold resistance (sticky at high temperature and brittle at cold), and can dissolve in solvents.

In industry, rubber can be used to make tires, dynamic and static seals, vibration absorbers, transmission belts, conveyor belts and pipes, wires, cables, electrical insulation materials and brakes.