Profile Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging and labelling, textiles (e.g., ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids. Properties Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Polypropylene is normally tough and flexible, especially when copolymerized with ethylene. This allows polypropylene to be used as an engineering plastic, competing with materials such as ABS. Polypropylene is reasonably economical, and can be made translucent when uncolored but is not as readily made transparent as polystyrene, acrylic, or certain other plastics. It is often opaque or colored using pigments. Polypropylene has good resistance to fatigue. • Perfectly isotactic PP: Melting Point : 171 °C (340 °F). • Commercial isotactic PP :melting point : 160 to 166 °C (320 to 331 °F), • Syndiotactic PP : crystallinity of: 30% has a melting point of 130 °C (266 °F). There are three general types of polypropylene: homopolymer, random copolymer, and block copolymer. The co-monomer is typically used with ethylene. Ethylene-propylene rubber or EPDM added to polypropylene homopolymer increases its low temperature impact strength. Randomly polymerized ethylene monomer added to polypropylene homopolymer decreases the polymer crystallinity and makes the polymer more transparent. Application: Polypropylene is used in many different settings, both in industry and in consumer goods. It can be used both as a structural plastic and as a fiber. Polypropylene is used in the manufacturing piping systems; both ones concerned with high-purity and ones designed for strength and rigidity (e.g. those intended for use in potable plumbing, hydronic heating and cooling, and reclaimed water). • This material is often chosen for its resistance to corrosion and chemical leaching, its resilience against most forms of physical damage, including impact and freezing, its environmental benefits, and its ability to be joined by heat fusion rather than gluing. • Since polypropylene is resistant to fatigue, most plastic living hinges, such as those on flip-top bottles, are made from this material. However, it is important to ensure that chain molecules are orientated across the hinge to maximise strength. • Very thin sheets of polypropylene are used as a dielectric within certain high-performance pulse and low-loss RF capacitors. • Many plastic items for medical or laboratory use can be made from polypropylene because it can withstand the heat in an autoclave. • Its heat resistance also enables it to be used as the manufacturing material of consumer-grade kettles. • 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. • Polypropylene, highly colorfast, is widely used in manufacturing carpets, rugs and mats to be used at home. • Polypropylene is widely used in ropes. • Polypropylene is also used as an alternative to polyvinyl chloride (PVC) as insulation for electrical cables for LSZH cable in low-ventilation environments, primarily tunnels. • Polypropylene is also used in particular roofing membranes as the waterproofing top layer of single-ply systems as opposed to modified-bit systems. Market Scenario There is a growing demand for propylene in the world today. The demand is driven primarily by the high growth rate of polypropylene, which is the main end use segment of propylene. The bulk of the propylene supply comes from steam crackers followed by the Fluid Catalytic Cracking (FCC) units in refineries. The supply of propylene from these processes is unable to meet the increasing demand. Most of the new steam cracker capacity is coming up with ethane feedstock, which produces little propylene and there is limited capacity expansion for FCC units. Thus, there is an increased dependability on purpose propylene technologies such as propane dehydrogenation, olefin metathesis and Methanol to Propylene (MTP) to meet the increased demand for propylene.
