Polypropylene homopolymer

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

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

Variation (%) relative to the value measured for neat homopolymer polypropylene. 

Instrument panel lower carrier on General Motors full-size trucks is made of a low-cost filled homopolymer polypropylene replacing a more-expensive filled SMA. 

Application To produce polypropylene-based polymers, including homopolymer polypropylene, random, heterophasic impact and specialty dual composition copolymers, using Spherizone process technology. 

Application A process to produce homopolymer polypropylene and ethylene-propylene random and impact co-polymers using Chisso Gas-Phase Technology utilizing horizontal plug-flow reactor. 

Application To produce propylene-based polymers including homopolymer polypropylene, random and heterophasic impact and specialty impact copolymers using Spheripol process technology. 

A homopolymer is a polymer formed from only one type of monomer. For example, homopolymer polypropylene is formed only from propylene monomers, so it has the following structure ... 

Polypropylene/dibromostyrene copolymer Sodium antimonate Tetradecabromodiphenoxybenzene flame retardant, PP homopolymers Polypropylene... 

Polyphenylene sulfide Polyphenylene sulfide sulfone Polyphenylene sulfone Polypropylene Polypropylene copolymer Polypropylene homopolymer Polypropylene oxide Polystyrene Polytetrafluorethylene Polyurethane Polyvinyl acetate Polyvinyl alcohol Polyvinyl carbazole Polyvinyl chloride... 

Four types of PP resins are available commercially homopolymer, random copolymer, impact copolymer, and reactor TPO. Homopolymer polypropylene (HPP) is the most difficult to impact enhance. All other types of PP are easier to modify because they contain varied amounts of ethylene linkages or ethylene-propylene bipolymers that reduce the stiffness of the base resin and increase its impact resistance. These structures also provide some degree of compatibility with -f ethylene-alpha olefin plastomers. Basic studies conducted using HPP in polypropylene-plastomer blends illustrate principles that apply to other types of PP as well. 

Polypropylene homopolymer, polypropylene copolymer, and a polypropylene elastomer blend (TPO) were melt compounded with 2.0,4.0, and 6.0 wt% additive. Additional tests with additive levels of 0.5,1.0 wt, and 1.5 wt% were made with Struktol TR-016. HiMod-360 mica was used at 30 wt% levels in all formulations, and there was a constant 0.2 wt% level of a stabilizer package in each compound. The maleic anhydride-modified polypropylene most effective in increasing performance properties was Unite MP-1000, but many other similar products made by a variety of companies performed nearly as well. To select the very best product, one must consider the relative costs of such additives and required use levels. 

Typical applications for homopolymer polypropylene include windshield washer tanks, shrouds for fans and steering columns, housings for domestic appliances such as hair dryers, sterilisers, irons, coffee makers, toasters, etc., extrusion of fibres and filaments for carpet backing, upholstery fabrics, clothing, geotextiles, disposable diapers, medical fabric and automotive interior fabrics. 

Coiqposltlon Acrylic acid modified homopolymer polypropylene Physical Form Pellets... 

Composition Maleic anhydride oiodifled homopolymer polypropylene... 

Firex 300C is recognized under the Conqtonent Program of Underwriters Laboratories Inc. for UL 94V-2 Flammability standard covering all colors and all melt flows of Homopolymer Polypropylene in a minimum 1 10 let-down ratio. 

Figure 16.24 Comparison of temperature-dependent elastic moduli for semicrystalline homopolymer polypropylene, amorphous polyvinyl chloride, and semicrystalline cyclic olefin copolymer (COC) showing that only homopolymer polypropylene has no appreciable thermoformable region.

Figure 16.26 Time-dependent strain rate behavior of homopolymer polypropylene showing lack of strain-rate hardening leading to inability to stretch into deep cavities.

Figure 16.27 The effect of adding strain-rate hardening polymers to homopolymer polypropylene allowing increasing ability to stretch into deep cavities.

Figure 16.28 Thermal energy required to heat thermoformable amorphous and crystalline polymers to their respective forming temperatures. HOPE, High density polyethylene at 960 kg/m MDPE, Medium-density polyethylene at 945 kg/m LDPE, Low-density polyethylene at 920 kg/m POM,- Polyoxymethylene PA-6, Polycaprolactam or polyamide PP, Homopolymer polypropylene, PS, General purpose polystyrene MIPS, Medium-impact or rubber-modified polystyrene ABS, Polyacrylonitrile-polybutadiene-polystyrene terpolymer PMMA, Polymethylmethacrylate FPVC, Flexible polyvinyl chloride RPVC, Rigid polyvinyl chloride.

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