Tensile strength characterizes the ultimate ability of the article to resist tensile failure
· Tensile strength of rubber:
Unfilled vulcanizate: Polyurethane rubber PUR> Natural rubber NR / Isoprene IR> Neoprene CR> Butyl rubber IIR> Chlorosulfonated polyethylene CSM> NBR / Fluorine rubber FKM> SBR rubber Ethylene-propylene rubber EPDM> styrene-butadiene rubber SBR> acrylic rubber ACM> chlorohydrin rubber CO> silicone rubber Q
Filling vulcanizate: Polyurethane rubber PUR> Polyester thermoplastic elastomer> Natural rubber NR / Isoprene IR> SBS thermoplastic elastomer> NBR / Neoprene CR> SBR / SBR EPDM / Fluorine rubber FKM> chlorosulfonated polyethylene CSM> butyl rubber IIR> butadiene rubber BR / chlorohydrin rubber CO> acrylic rubber ACM> silicone rubber Q

Under rapid deformation, the tensile strength of rubber is higher than that at slow deformation; the tensile strength tested at high temperature is much lower than the tensile strength at room temperature.

· Effect of vulcanization system
For commonly used soft vulcanizates, if you want to improve the tensile strength through the vulcanization system, you should use the traditional vulcanization system of sulfur-accelerator, and appropriately increase the amount of sulfur. At the same time, the accelerator is selected from thiazoles such as M, DM and guanidine. Use them together and increase the dosage appropriately.

· Impact of the filling system
* The smaller the particle size of the filler, the larger the specific surface area and the greater the surface activity, the better the reinforcing effect.
* Crystalline (such as natural rubber) -based vulcanizates.The tensile strength can increase monotonically with the amount of filler.
* Non-crystalline (such as styrene-butadiene rubber) -based vulcanizates, the tensile strength increases with the amount of filler, reaches a maximum, and then decreases.
* Low unsaturation rubber (such as ethylene-propylene-diene rubber, butyl rubber) -based vulcanizate, the tensile strength increases with the increase in the amount of filler, which can remain unchanged after reaching the maximum value.
* For thermoplastic elastomers, the filler reduces its tensile strength.
* In general, when the amount of carbon black in soft rubber is 40-60 parts, the tensile properties of vulcanizates are better.

· Impact of softening the system
In general, the addition of softeners will reduce the tensile strength of vulcanized rubber. However, when the amount of softener does not exceed 5 parts, the tensile strength of vulcanized rubber may increase. Because it contains a small amount of softener, the dispersion effect of carbon black is good. .
* Aromatic hydrogen oil has little effect on the tensile strength of non-polar unsaturated rubber (isoprene rubber, butadiene rubber, styrene butadiene rubber) vulcanizate. Dosage 5-15 parts
* Paraffin oil has a great influence on the tensile strength of non-polar unsaturated rubber (isoprene rubber, butadiene rubber, styrene butadiene rubber) vulcanizate.
* For polar unsaturated rubber (such as NBR, neoprene), it is best to use aromatic hydrogen oil and ester softener (such as DBP, DOP, etc.)
Other methods to improve the tensile strength of vulcanizates:
* Rubber is blended with certain resins; such as natural rubber, styrene-butadiene rubber and high-styrene resin. Natural rubber and polyethylene are blended. NBR and polyvinyl chloride are blended, ethylene-propylene rubber is blended with polypropylene .
* Chemical modification of rubber.
* Modification of filler ==> Use surfactant or coupling agent.