Polypropylene homopolymers

Catalyst Development. Traditional slurry polypropylene homopolymer processes suffered from formation of excessive amounts of low grade amorphous polymer and catalyst residues. Introduction of catalysts with up to 30-fold higher activity together with better temperature control have almost eliminated these problems (7). Although low reactor volume and available heat-transfer surfaces ultimately limit further productivity increases, these limitations are less restrictive with the introduction of more finely suspended metallocene catalysts and the emergence of industrial gas-phase fluid-bed polymerization processes. 

The higher transparency coupled with the rigidity expected of a conventional polypropylene homopolymer is of particular interest in thin-wall moulding applications. 

Relatively small changes in comonomer content can result in significant changes in physical or chemical properties. Polymer resin manufacturers exploit such relationships to control the properties of their products. The composition of a copolymer controls properties such as stiffness, heat distortion temperature, printability, and solvent resistance. For example, polypropylene homopolymer is brittle at temperatures below approximately 0 °C however, when a few percent ethylene is incorporated into the polymer backbone, the embrittlement temperature of the resulting copolymer is reduced by 20 °C or more. 

A foamable isotactic polypropylene homopolymer is obtained by metallocene catalysis and has a molecular weight distribution and density, which fall within broad ranges. It may be prepared in a multiple stage polymerisation process nsing the same metallocene component in at least two stages. 

Patent Number US 5747549 A 19980505 FOAMED PARTICLES OF POLYPROPYLENE HOMOPOLYMER AND MOULDED ARTICLE OF THE FOAMED PARTICLES... 

A comparison is made between a 3.5 melt flow conventional polypropylene homopolymer (Profax 6523) and a 7.0 melt flow, high-melt-strength, foamable PP homopolymer in extensional flow. The importance of extensional or elongational viscosity in the foam process is demonstrated and the way in which the rheological differences permit the production of low-density foam on tandem extrusion equipment is shown. 6 refs. 

Mostly isotactic polypropylene homopolymer, but some copolymer with polyethylene, and some HOPE A high molecular weight is needed, 170,000-300,000, for good mechanical strength because of weak intermolecular forces, only van der Waals. 

Monofilament yarns consist of a single filament. The filament size is much larger than those found in multifilament yarn. Consequently, monofilament is relatively stiff and is used mainly for the production of rope and twine. Fiber size range is typically 75 to 5000 denier. Monofilament fiber is usually produced from polypropylene homopolymer with a relatively low melt flow index in the range 3.5 to 5.0 grams/10 min. 

Injection molded test specimens. PP = Marlex polypropylene homopolymer (nominal 5 melt flow). 

Polypropylene homopolymer (PP) is a widely used thermoplastic material, despite its brittle behaviour at either low temperature or high loading rates. Improvement in the fi acture toughness of PP can be achieved by either modifying the crystalline structure, or addition of a second phase material [16], The toughening effect and mechanisms of different second phase materials such as stiff fibres, soft rubbery inclusions (EPR, EPDM), and some mineral fillers have been analysed. Recent developments concern the effect of hybrid system consisting of rigid and rubbery inclusions. 

Isostatic polypropylene homopolymer, with a weight-average molecular weight Mw of 345 kDa, a melting point of about 160°C and a density of 0.902, was used as matrix material ELTEX... 

Material of Construction - Polypropylene Homopolymer Tank Size - 32 Long x 5 Wide x 4 Deep... 

The five most economical plastics are the polyethylenes (ultra low, low, linear low, medium and high density), polypropylenes (homopolymer and copolymer), polyesters, polystyrenes and polyvinylchlorides (unplasticised and plasticised) and as a result these are the materials most widely used by the pharmaceutical industry. Polyethylene and polypropylene may also be grouped under olefins . The list of plastics which follows is given alphabetically rather than in any order of use. 

General-purpose polypropylene homopolymer (minimum requirements)... 

COMPOSITION OF WOOD-PLASTIC COMPOSITES MINERAL FILLERS TABLE 4.3 Effect of inorganic fillers and wood flour on flexural strength and flexural modulus of polypropylene (homopolymer) [2] ... 

General resistance of several generic plastics to oxidation is shown in Table 15.1. LDPE is the least resistant and polypropylene homopolymer is the most resistant, whereas HDPE takes an intermediate place. Resistance of unsaturated C=C aliphatic polymers is quite low because of the ease of abstraction of hydrogen atom. 

High density (HDPE), 52 Irregularities, 52 Linear low density (LLDPE), 52 Low density (LDPE), 52 Molecular weight, 52 Melt flow index, 53 Melting temperature, 51 Moisture absorption, 51 Polymeric forms, 52 Resistance to chemicals, 52 Resistance to oxidation, 52 Shrinkage, 54 Unsaturations, 54 a-transition, 51 P-transition, 51 y-transition, 51 Polyisocyanate, 79 Polylactic acid, 79, 91 Polymer alloys, 48 Polymer processing additives, 646 Polymer rheology, 619 Polymeric forms, 52 Polyphase PlOO, 451 polypropylene (PP), 2, 11 Polypropylene homopolymer, 70... 

ConpolP. [Consolidated Polymers Ltd.] Polypropylene homopolymers and copolymers. 

PP-. [Washington Penn Plastics] Polypropylene homopolymers or copolymers, some mineral or glass-reinforced for automotive parts, furniture, toys, appliances, lawn equip., pump housings, instrument pands, housewares, closures and containers for foods/drugs. 

Astryn . [Himont] Polypropylene homopolymer and copolymers, some glass and mineral-reinforced for automotive parts, housewares, lawn and garden tools/houstngs, appliance housings, ABS replacement... 

Fortilene . [ Ivay Polymers] Polypropylene homopolymers andcopolyrtras resins for extrusion, sheet, strapping, profiles, inj. molding, caps, closures, thin-wall containers, disposable tableware, films, fibers, filaments. 

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