1. Composition of rubber

Rubber products are composed of raw rubber with an appropriate amount of additives added.

(1) Raw rubber refers to natural or synthetic rubber that has not been compounded or vulcanized. Natural rubber has good comprehensive performance, but its production cannot meet the needs of industry, nor can it meet certain special performance requirements, so synthetic rubber is widely used.

(2) A substance added to improve and enhance the various properties of rubber products is called a compounding agent. The main additives include vulcanizing agents, fillers, vulcanizing accelerators, plasticizers, anti-aging agents, and foaming agents.

① The effect of vulcanizing agent is similar to that of curing agent in thermosetting plastics. It forms transverse chains between rubber molecular chains, appropriately crosslinks, and forms a network structure, thereby improving the mechanical and physical properties of rubber. The commonly used sulfur compounds are sulfur and sulfides.

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 metal wires or metal woven fabrics used as skeleton materials. Adding fillers can also reduce the amount of raw rubber used and lower the cost of rubber.

③ Other vulcanizing agents can accelerate the vulcanization process and improve the vulcanization effect; Plasticizers are used to increase rubber plasticity and improve molding process performance; Antioxidants are used to prevent or delay rubber aging.

2. Characteristics and Applications of Rubber Products

Rubber products have the characteristics of high elasticity, high resilience, high strength, and high wear resistance. Its elastic modulus is very low, only 1-10MPa, and the elastic deformation is large, reaching 100% to 1000%. It has excellent elasticity and energy storage capacity. In addition, it has good wear resistance, sound insulation, damping, and insulation properties. However, rubber has poor heat and cold resistance (it becomes sticky when exposed to high temperatures and brittle when exposed to cold), and will dissolve in solvents.

Rubber can be used in industry to make tires, dynamic and static seals, vibration damping and isolation components, transmission belts, transport belts and pipelines, wires, cables, electrical insulation materials, and braking components.