During the vulcanization process, due to the cross-linking effect, the active functional groups or double bonds in the rubber macromolecular structure are gradually reduced, thereby increasing the chemical stability. On the other hand, due to the formation of a network structure, the movement of the rubber macromolecular segments is weakened, and the diffusion of low-molecular substances is severely hindered. As a result, the stability of the rubber's action on chemical substances is improved.
Vulcanizing agent is a substance that connects adjacent rubber macromolecular chains in the form of chemical bonds under certain conditions.
Vulcanizing agents are mainly divided into seven categories: sulfur, sulfur donors, organic peroxides, metal oxides, organic quinones, resin curing agents, and amine curing agents.
There are many types of rubber additives and their functions are more complicated. There are currently more than 3000 kinds of rubber additives in use internationally. According to its properties, it can be classified into the following categories: vulcanizing agents, accelerators, active agents, reinforcing fillers, plasticizers, antioxidants, coloring agents, as well as special additives for latex and other special purpose additives.The main vulcanizing agents are as follows.
(1) Elemental sulfur vulcanizing agent
(2) Sulfur donor
(3)Peroxide curing agent
(4) Metal oxide vulcanization system
(5) Derivatives of quinone
(6) Resin curing agent
(7) Amine compounds