High-impact polypropylene

Finally, in the fourth section the fundamentals of the modelling concerning two basic olefin polymerization processes are examined heterogeneous slurry polymerization and gas-phase polymerization. The SPERIPOL process for making High Impact PolyPropylene (HIPP) is then described as an illustrative example for combining fundamentals and elements of product and technology development. 

Nowadays, the leading two polyolefin companies are producing more than 20 million metric tons of polyethylene (PE) and polypropylene (PP) annually. This is about 35% of the world production of all POs. The demand for high impact polypropylene HIPP, and linear low density polyethylene, LLDPE, especially (see Fig. 5.4-2) is permanently growing at about 7% per year. "Distance holders", such as the methyl groups and the butene branch shown in Fig. 5.4-2, help to control the degree of crystallinity, and consequently the processability. 

The predominant system for controlle-rheology reactive extrusion is polypropylene (PP) with systems such as ultrahigh-melt-flow polypropylene, high-impact polypropylene blends... 

A comparison between different LMW-HALS in a dark gray colored high impact polypropylene copolymer is shown in Table 17.9. In this case the HALSs with the lowest molecular weight performed best. 

Flexural modulus of neat polypropylene is similar with that of HDPE and is in the range of 170,000-250,000 psi. Flex modulus for high-impact polypropylene is of 100,000-... 

Fig. 19 TREF analysis of a high impact polypropylene. The small peak at 98°C corresponds to PE homopolymer, as deducted from the CH3/IOOOC signal...

Polyolefin Blends as Models for High-Impact Polypropylene Co-polymers (HIPCs)... 

Fiarticle morphology porosity, relative length scale of polymer and pore phases, particle shape, distribution of phases in high-impact polypropylene Interphase heat and mass transfer phenomena Intraphase heat and mass transfer phenomena Observed kinetics, rate limiting steps Phase equilibrium, monomer sorption and desorption in polymer phase, diffusion Fbrticle agglomeration Micromixi ng... 

Over the last thirty years, synthetic polymer materials have become more and more common in our everyday lives. At breakfast, we have bottles of orange juice made of polyethylene. Our car bumper is made of high impact polypropylene, the interior is largely composed of polyurethane, the tyres are elastomers and parts of the bodywork are polymer mixtures. Our clothes are made from polyester, polyamide and acrylic fibres. We seem to be overwhelmed with what we commonly refer to as plastics , although incorrectly, as we shall see later. 

AFM is used at the nanoscale to analyze structure of polymers. It has been used to determine spatial distribution of impact modifier in high impact polypropylene (95), follow pit growth in a film of a blend as a function of exposure time during degradation studies of coatings on metal (96), determine surface topography and molecular organization of liquid crystalline polymers (97), and observe... 

High-impact polypropylene More durable than polyethylene, not as stiff tendency to crack at temperatures below 0°F (-18°C)... 

The oldest example of this procedure is the manufacture of high-impact polypropylene, as already described (see Section 8.1.2). Other applications have become more popular lately, especially for the production of bimodal resins. Figure 8.36 illustrates a tandem process using two gas-phase vertical stirred-tank reactors. Several other reactor combinations are used industrially [65]. For heterogeneous processes, the first reactor(s) in the series can be either slurry or gas-phase, but commonly the second reactor (or set of reactors) is a gas-phase reactor. This is especially important when the production of polymers with lower crystallinity... 

Consider first the case of two tubular reactors in series, making high-impact polypropylene. Reactor 1 produces isotactic polypropylene, while random ethylene-propylene copolymer is made in Reactor 2. Assuming that both reactors are ideal plug-flow reactors, the residence time of all the polymer particles in each reactor is exactly the same. Consequently, if the distribution of active sites in the... 

Gas-phase reactors, especially fluidized-bed reactors, are the most common configuration for the polymerization of ethylene to produce HOPE and LLDPE. They are also a very common choice for the second reactor in the production of high-impact polypropylene. 

Less crystalline copolymer chains can dissolve in the diluent - particularly the ethylene-propylene copolymer fraction in high-impact polypropylene -causing fouling and increasing the viscosity of the diluent. Therefore, certain low-crystallinity grades cannot be produced with these reactors. 

KRO Kroner, T. and Bartke, M., Sorption of olefins in high impact polypropylene Experimental determination and mass transport modeling, Macromol. React. Eng., 1, 453,2013. 

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