Polypropylene, production

This is often conducted to make impact-resistant polyolefin blends. For this purpose, isotactic polypropylene, which is tough but somewhat brittle, is produced on the catalyst pellet in a first reaction step, using highly active stereospecific 

Amoco-Chisso Process This process resembles the Novolen process except that the two reactors connected in series are stirred horizontally with blades and operated at 90°C and 20 bar. Polymers produced with the Amoco-Chisso technology show high uniformity, as particle residence time distribution in the reactor is particularly narrow. 

Fluid-Bed Process Union Carbide and Shell technologies are combined in this process Two fluidized-bed reactors are used in series to produce impact-resistant polypropylene. As with other processes, reaction conditions are 50-100°C and 10-40 bar, with particle residence times between 1 and 4 hours. 

Due to the use of advanced, highly active and selective solid-state catalysts (sections 7.3), the processes described above produce polymers from which neither stereoirregular polymer components nor catalyst residues need be removed. This has resulted in substantial reductions in the costs of investments, energy and maintenance, compared to slurry processes with first-generation catalysts. Ongoing developments are aimed at increased process flexibility and at process adaptation to the use of supported metallocene catalysts (Section 7.4). 

Discussion Point DP2 Olefin polymerization is an exothermic process. Estimate the heat of reaction released per day by a polymerization reactor with a typical production capacity of about 1000 t of PE or PP per day. Identify the means which can be used to remove this amount of heat from the reactor. What are their relative merits (and limits) in terms of energy use or recycling Some (e.g. cationic) polymerization reactions proceed rapidly and give products with excellent properties when conducted at temperatures below 0°C. What makes such processes uneconomical  

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Eastman Chemical has utilized a unique, high temperature solution process for propylene polymerization. Polymerization temperatures are maintained above 150°C to prevent precipitation of the isotactic polypropylene product in the hydrocarbon solvent. At these temperatures, the high rate of polymerization decreases rapidly, requiring low residence times (127). Stereoregularity is also adversely affected by high temperatures. Consequentiy, the... 

Table 11. U.S. Polypropylene Production, Capacity Utilization, and Prices ...

Table 11.8 Market breakdown for USA polypropylene Production (based on data in Modern Plastics International)...

Figure 11 Homopolymer polypropylene product range with metallocenes. (From Ref. 29, with permission from Sterling Publications Limited.)...

Polypropylene (PP) is a major thermoplastic polymer. Although polypropylene did not take its position among the large volume polymers until fairly recently, it is currently the third largest thermoplastic after PVC. The delay in polypropylene development may be attributed to technical reasons related to its polymerization. Polypropylene produced by free radical initiation is mainly the atactic form. Due to its low crystallinity, it is not suitable for thermoplastic or fiber use. The turning point in polypropylene production was the development of a Ziegler-type catalyst by Natta to produce the stereoregular form (isotactic). 

Polypropylene fibers represent a small percent of the total polypropylene production. (Most polypropylene is used as a thermoplastic.) The fibers are usually manufactured from isotactic polypropylene. 

Extraction of antioxidants in polypropylene production. Process control. 

We find an additional crystalline structure in rapidly quenched isotactic polypropylene products. In these materials, the polymer chains do not have the necessary time to orient,... 

Polypropylene products can be identified with the recycling symbol containing the number 5 with the letters PP underneath the symbol. Several important characteristics of polypropylene are compared to polyethylene in Table 76.1. 

Occupational exposure to isopropanol may occur in polypropylene production plants... 

The UNIPOLw process for polyethylene and polypropylene production using the Ziegler-Natta2 catalyst see Section 7.3. 

Dwyer SM, Boutini OM, Shu C (1996) Compounded polypropylene products. In Moore EP (ed) Polypropylene handbook. Hanser, Munich, p 211... 

The chiral complex EBTHI—Ti is an excellent chiral catalyst [40]. This complex is a derivative of titanocene and used as the Kaminsky catalyst, which has brought epoch-making progress in polypropylene production. The chiral bridged titanocene complex is used for the production of optically active polypropylene arising from the helical structure of the polymer chain. The chiral complex also behaves as an excellent... 

A flow scheme of polypropylene production involving the slurry process with the removal of catalyst residues from the polymer is presented in Figure 3.52 [51],... 

Figure 3.53 Flow scheme of polypropylene production using the slurry polymerisation process...

The commercial production of high-density polyethylene started almost at the same time in late 1956 by Phillips using a chromium-based catalyst in a medium-pressure process and by Hoechst using a Ziegler catalyst in a low-pressure process. Polypropylene production began in Montecatini and Hercules plants in 1957. Poly(l-butene) and poly(4-methyl-1-pentene) have been produced in small commercial quantities since about 1965. The commercial production of ethylene/propylene-based rubbers started in 1960 [241]. 

Polyolefin Production Plastic Resin Polypropylene Production Polyethylene Production... 

Products A wide range of polypropylene products (homopolymer, random copolymer and impact copolymer) can be produced to serve many applications, including injection molding, blow molding, thermoforming, film, extrusion, sheet and fiber. Impact copolymer produced using this process exhibits a superior balance of stiffness and impact resistance over a broad temperature range. 

Almost all current large-scale polymerization plants for catalytic polyethylene and polypropylene production are suited only for the use of solid-state... 

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