Rubber

Synthetic rubber is

• the original name given to latex

• derived from 'elastic polymer'

Tags

NGSS.MS-PS1-3

thermoplastic elastromers is

• polymer that possesses the quality of rubber

• vulcanised rubber

• do not required crosslinking

• rubbery material that combine the characteristics of rubber with the recyclability and processing advantages of plastics

elastromer is

• polymer that displays elastic properties

• crosslinked rubbber

Thermoset elastomer is

• crosslinked rubber

• undergo a chemical change during processing (vulcanization) to become permanently insoluble and infusible

• elastic polymer

natural rubber is

• an elastic hydrocarbon polymer that naturally occur as a milky colloidal suspension (latex) in the sap of the rubber tree.

• 
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• natural rubber is not the natural polymer of isoprene

Tags

NGSS.MS-PS1-1

coagulation of rubber is

• the preferred method of recovering rubber from latex by adding acid such as formid acid

• coagulation take less than 12 hours

the next step after coagulation of rubber from natural latex is

• squeezed through a series of rolls

• the sheets are then drape over a wooden frames

• dried in the smokehouses

• end product is not soft sticky and thermoplastic

Vulcanization process is

• a cross linking process in whivh indivudual molecules of rubber are converted into 3D network of interconnected polymer chain through chemical cross links.

• the elastromer must contain chemical unsaturation (c=c double bonds) for sulphur cross linking

Tags

NGSS.MS-PS1-1

what step comprises in sulphur vulcanization?

• Mixing of crude rubber with about 5-30% of sulfur (cross-linking agent) and other additives

• Molding (shaping) the rubber mixture: extrusion, calendering, coating and molding & casting.

• Heating the mixture to 250-400ºF (120-200ºC). Increased temperature speeds up the vulcanization process resulting in fast and complete cross-linking

• vucanized in the smokehouses

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4