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Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene . Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar .
This plastic is processed by injection molding or extrusion; depending on the type, the processing temperature is 260–300 °C. The surface can be printed, hot-stamped, painted or metallized. Welds are possible by means of heating element, friction or ultrasonic welding. It can be glued with halogenated solvents or various adhesives.
Polypropylene is commonly used in car bumpers, interior trims, and other components [19] where TiO₂ is added to improve the UV stability of the plastic, ensuring that parts do not degrade or lose color when exposed to sunlight over time. [20] Polyethylene films are widely used in agriculture for greenhouses, mulching, and silage wraps. [21]
The PP and PE components of a blend constitute the "crystalline phase", and the rubber and branched PE chains and PE/PP end groups gives the "amorphous phase". If PP and PE are the dominant component of a TPO blend then the rubber fraction will be dispersed into a continuous matrix of "crystalline" polypropylene.
The development of plastics has evolved from the use of naturally plastic materials (e.g., gums and shellac) to the use of the chemical modification of those materials (e.g., natural rubber, cellulose, collagen, and milk proteins), and finally to completely synthetic plastics (e.g., bakelite, epoxy, and PVC).
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Polypropylene carbonate is used to increase the toughness of some epoxy resins. It is used as a sacrificial binder in the ceramic industry, which decomposes and evaporates during sintering . It has a low sodium content which makes it suitable for the preparation of electroceramics like dielectric materials and piezoelectric ceramics.
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