Crosslinking is the foundation of high elastic rubber, its characteristic is in a rubber molecule chain formed only a few several junction, so will not affect the rubber molecular chain segments. Rubber vulcanization system, more common are: sulfur curing system, peroxide vulcanization system, resin curing system, oxide vulcanization system, etc
3.1.1 sulfur curing system
Mainly suitable for diene rubber, its vulcanization activity is next to the double bond of alpha hydrogen atoms. Composition: sulfur; Surfactant: zinc oxide, stearic acid; Accelerator: thiazole class (DMM), times sulfonamide classes (CZ, NOBS), thiuram class (TETD, TMTM, TMTD)
Common peroxides are: DCP (dry base peroxide), BPO, DCBP, helps the crosslinking agent: inhibition of aggregation difficult radical useless side effects. Such as TAIC, TAC, HVA - 23
Peroxide vulcanized rubber performance characteristics: aging performance is good, compression permanent deformation is small, good transparency.
3.1.2 oxide vulcanization system which is mainly containing halogen rubber vulcanizing agent. Usually have zinc oxide/magnesium oxide (5/4), lead or red lead (10-20, water resistant products)
3.2 packing without filler of rubber and rubber mechanical properties and process performance is poor, cannot use.
Reinforcement: tensile strength, tear strength, abrasion resistance, processability, reduce the cost
3.2.2 packing structure
18.104.22.168 particle size
In general, the smaller the particle size, the higher the strength.
22.214.171.124 chemical structure
Reactivity (PH). Such as carboxyl group on the surface of the carbon black, silica and ordinary light color packing surface, such as hydroxyl acid packing often influence of rubber vulcanization, therefore need to join the surfactant, eliminate the acid. 126.96.36.199 packing packing surface processing method for hydrophilic commonly, the polymer is hydrophobic, the compatibility is poorer, surface treatment must be conducted.
188.8.131.52 surfactants (1) structure: organic compound, with the molecular structure of the asymmetry, composed of hydrophilic and hydrophobic groups in two parts. (2) the hydrophilic part: - OH, - COOH, NH2, - NO2 - SH. (3) hydrophobic parts: long chain, benzene ring type or hydrocarbons
184.108.40.206 coupling agent (1) classification: silane and titanate and aluminate ester, polymer coupling agent, etc. (2) structural characteristics: hydrophilic part and surfactant are similar, but the hydrophobic part can be combined with polymers to form chemical or physical tangles. (3) the impact on performance: low molecular coupling agent is usually lower viscosity at the same time, improve the mechanical properties; Macromolecule coupling agent are greatly improved mechanical properties at the same time, increase the viscosity of the system, it is because of the forces between molecules increase.
3.3 softener and plasticizer
3.3.1 softener (1) the effect of lower the viscosity of the system, increase liquidity, lower sulfur