Rubber Processing

 Mixing, shaping and curing are the main three stages in rubber processing. Mixing with different compounding ingredient is done to increase chemical and physical properties of the rubber. That also known as rubber compounding. There are three general processes for shaping called molding, extrusion and calendering. after shaping curing is done for improve hardness of rubber product  by forming cross links in rubber chains. That is also called vulcanizing.  

 Now a day’s both natural rubber and different synthetic rubbers are used for rubber processing.

• Natural rubber(NR)

Chemical structure of Natural Rubber

Natural rubber is latex taken from the tree Heavea Brazilianzis

which is generally known as rubber tree. NR has excellent tensile strength and elongation. Its abrasion resistance, tear resistance, fatigue resistance and electrical resistance also high. NR formula has unsaturated double bonds, so its weather resistance is poor. Not only that natural rubber is dissolved in non polar chemicals like oils, petroleum based fuels etc.

Natural rubber is used as both liquid (latex rubber) and solid form (dry rubber) for processing. Some applications of these two types, some processing methods and advantages & disadvantages are summarized below.

	Applications	Processes	Advantages
Latex rubber	Gloves, Balloons	Dipping, tubing	Simple machinery can use,low energy  consumption
Dry rubber	Tires,  o rings, engine mounts	Extrusion, molding	Easy to transport and store

• Synthetic rubbers

Synthetic rubbers are made by polymerisation of different petrolium based monomers. Some of synthetic rubbers are Isoprene rubber(IR), Styrene Butadiene Rubber(SBR), Isoprene Isobutaline Rubber(IIR), Ethelene Propelene Rubber(EPR), Chloroprene Rubber(CR), Silicon Rubber etc.

 Those synthetic rubbers have different properties, so they have different applications and different processing methods. they will be explained in future.