Polypropylene Case Study

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In various traffic mishaps that take place around the globe, side impact collision are not only frequent, but they also result in very harmful accidents. According to global accident statistics, about 30% of all impacts are side impact crashes, and account for 35% of total fatalities. The front and rear zone of the car have a considerable amount of crush zone, for absorbing impact energy, but this is not the case for side impacts. Side impacts have a considerably reduced crash zone for absorbing impact energy at the side, thus side impacts requires more attention, in part design and use of energy absorbing material. Side impacts require special attention because during side impact accidents the occupant sits within the crash zone, thus often Polypropylene is one of those most versatile polymers available with applications, both as a plastic and as a fiber, in virtually all of the plastics end-use markets.[3] Production of polypropylene takes place by slurry, solution or gas phase process, in which the propylene monomer is subjected to heat and pressure in the presence of a catalyst system. Polymerization is achieved at relatively low temperature and pressure and the product yielded is translucent, but readily colored. Differences in catalyst and production conditions can be used to alter the properties of the plastic. Propylene is obtained, along with ethylene, by cracking naphtha (crude oil light distillate). Ethylene, propylene, and higher alkenes are separated by low temperature fractional distillation.[3] Polypropylene is a relatively easy material to injection mold in spite of its semi crystalline nature. The absence of any real need for high molecular weight, from the mechanical properties view point, leads to low melt viscosity (easy flow). The pseudo plastic nature of polypropylene enhances this effect at high shear rates (fast filling rates). Typically melt temperatures for injection molding are between 200 and 250oC, though they can be as high as 280, or even 300oC, for short periods of

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