Polypropylene is the second-most widely produced commodity plastic (after polyethylene). White opaque PP film is produced by incorporating particulates such as titanium dioxide in homopolymer resin. In one variation, a small amount of particulate creates air-filled voids when the PP pulls away from the particles during orientation, producing a film with density much lower than the 0.9 g cm−3 that is typical of PP.

  • Its chemical resistance makes it useful as a material for solvent containers.
  • It is a PP homopolymer with a co-mixed PP random copolymer phase, containing between 45 – 65% ethylene.
  • Polypropylene (PP) is one type of thermoplastic that has been grown to its special characteristics such as low cost and density, versatile physical properties, and high heat distortion temperature (HDT) [27].
  • Polypropylene fibres are also used in drywall joint compound for reinforcement.

Pristine PP is impervious to photo-oxidation and thermal oxidation at modest temperatures. Furthermore, PP is sensitive to several external stimuli like temperature, light, and irradiation. Under exposure to high energy conditions, oxygen may attack the tertiary hydrogen of the PP unit (Murphy et al., 1996). Oxidation PP depends on both can i get a tax refund with a 1099 even if i didn’t pay in any taxes light irradiation and temperature in outdoor aging circumstances. Furthermore, In the wavelength range from 310 to 350 nm, various molecular chains of PP are suspected to be photodegraded. These catalysts are activated with special cocatalysts containing an organoaluminum compound such as Al(C2H5)3 and the second type of a modifier.

What are the properties of PP?

The large number of end-use applications for polypropylene are often possible because of the ability to tailor grades with specific molecular properties and additives during its manufacture. For example, antistatic additives can be added to help polypropylene surfaces resist dust and dirt. Many physical finishing techniques can also be used on polypropylene, such as machining. Surface treatments can be applied to polypropylene parts in order to promote adhesion of printing ink and paints. The properties of PP are strongly affected by its tacticity, the orientation of the methyl groups (CH3) relative to the methyl groups in neighboring monomer units (see above). The tacticity of polypropylene can be chosen by the choice of an appropriate catalyst.

Some plastics, like those that contain BPA or other harmful chemicals, can negatively affect our bodies or the world we live in. We connect engineers, product designers and procurement teams with the best materials and suppliers for their job. Atactic polypropylene, on the other hand, lacks any regularity which makes it unable to crystallize and amorphous. Connect and share knowledge within a single location that is structured and easy to search.

Optical properties

Some surgical devices and implants are also made of polypropylene, and polypropylene fibers are commonly used to weave area rugs for indoor and outdoor use. Ethylene-containing co-monomers (1 – 7% ethylene) are positioned in irregular patterns throughout the PP molecule. It has high flexibility and optical clarity, suitable for applications with optical transparency and good appearance requirements. Very thin sheets (≈2–20 µm) of polypropylene are used as a dielectric within certain high-performance pulse and low-loss RF capacitors. Polypropylene is also used in particular roofing membranes as the waterproofing top layer of single-ply systems as opposed to modified-bit systems.

Stress-cracking is not an issue for PP as it also displays good levels of corrosion resistance. A common application for polypropylene is as biaxially oriented polypropylene (BOPP). These BOPP sheets are used to make a wide variety of materials including clear bags. When polypropylene is biaxially oriented, it becomes crystal clear and serves as an excellent packaging material for artistic and retail products. Another type of metallocene catalysts produce syndiotactic polypropylene.[26] These macromolecules also coil into helices (of a different type) and crystallize.

Dictionary Entries Near pp

PP may stimulate the immuno-competent cells of patients with prosthetic implants. The extent of foreign-body reactions is also influenced by PP filament structure and surface area, both of which favour monofilament materials. Tissue response to lightweight PP is characterised by a lower chronic inflammatory response than heavyweight PP. PP has been used as non-biodegradable sutures in eye operations and also in heart-valve structures. Complications that may occur following implantation of any surgical mesh include infection, inflammation, fistula formation, extrusion and adhesion formation when placed in direct contact with the intestine.


Transfer food into a glass or metal container before you heat it, and don’t reuse containers that are intended as single-use packaging. It exhibits distinctive properties, such as high impact resistance, energy absorption, thermal insulation, and high strength-to-weight ratio. It is also used in many industries, such as automobiles, construction, and packaging. It is semi-crystalline, solid, contains only PP monomers, and is suitable for a wide variety of applications, from plastic packaging to automotive and healthcare.

Polypropylene exhibits excellent chemical resistance to most solvents, disinfectants, lipids, and bleaches. Applications for drug delivery, luer components, connectors, syringes, and labware take advantage of the clarity and chemical resistance of the polymer. Bisphenol A (BPA) is a chemical used in the manufacturing of polycarbonate plastics. It’s also used in epoxy resins that coat the insides of canned goods and water supply pipes.


Polypropylene is resistant to many polar liquids such as alcohols, organic acids, esters, and ketones. Aliphatic, aromatic, and halogenated hydrocarbons will swell polypropylene (Table 5.20). The extent of swelling will depend upon the percentage of crystallinity (the less crystalline and more amorphous the material, the greater the swelling).

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