The polypropylene , of chemical formula - (CH2-CH-CH3) n-, is a Polymère obtained by the Polymérisation of the monomers of Propylène (CH2=CH-CH3).
The polypropylene is a polyolefin, a material resulting from the polymerization of the propylene monomers (CH2=CH-CH3) in the presence of catalysts according to the Ziegler-Natta process. The polyolefins are unsaturated hydrocarbon monomers whose general formula is R=C R 1 R 2 (R1 and R2 are groupings such - H, - CH3, - CH2-CH (CH3) 2)
The general formula of polypropylene is the following one: (CH2 - CH-CH3) N
HistoryGiulio Natta obtained, in 1954, a polypropylene with regular crystalline geometrical structure starting from an amorphous product. It employs the isotactic term to describe this polymer. The molecules of an isotactic polymer can approach the ones the others to give an ordered solid.
Later, it will develop stereospecific Catalyseur S allowing systematic obtaining such polymers.
- Melting point: 145 ~ 170°C
- Temperature of vitreous transition Tg: -60 ~ -10°C
- Density: ~ 0,9
- Modulus Young: ~ 1,5 GPa
The polypropylene, summary PP, with a rank of injection, is very easily Recyclable, whereas PP " film" is on the contrary much more delicate to recycle especially if it is printed. PP printed film is surely one of the usual plastics most difficult to recycle.
The expanded polypropylene, shortened EPP (English initials), is a white foam resembling the expanded Polystyrène, but with a memory of form enabling him to become deformed without breaking and to preserve its structure.
ApplicationsOne finds much polypropylene in the automobile equipment, in particular the bumpers, the instrument panels and the preparing of the cockpit. The polypropylene is used also much for the food Emballage S for its resistance to the Graisse like butter packing, its transparency and its brilliant aspect. It is also used for the manufacture of the Géotextile S and of Géomembrane S and one also finds it in the form of fiber in the plastic cords and the synthetic carpets.
The tickets of the Australian currency are made by it.
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