How is polypropylene fiber made?
• Extraction of monomer: Alkenes or the monomer is extracted during the cracking of petroleum. The monomer obtained is propylene.
• Polymerization: Propylene monomers then join end to end to form a polymer by addition or chain-growth polymerization. The polymer so formed is called polypropylene. The propylene gas is polymerised into polypropylene using titanium chloride.
• Mixing: Polypropylene is then mixed with a diluent followed by filtration and purification. The mixing process is done to obtain polypropylene resins while the diluent decomposes the catalyst.
• Conversion of polymer to filament: The resins are then converted to filament fibers that are further used for textile construction purpose. But the conversion of resin to filament can be done using either of the two methods that are melt spinning or formation of sheets.
• Melt spinning: The process of melt spinning involves feeding of the resins into a hopper which is heated and this heat converts resins into molten liquid. The molten liquid is allowed to pass through the spinneret (a sieve-like device that has holes) and upon extrusion, the filaments harden when cool air is passed.
The other method involves the application of plasticizers, stabilizers and fillers on the resins. Followed by extrusion of the molten polymer in the form of sheets. The sheets are then pulled or cut and made into yarn.