Science, Tech, Math › Science Understanding Polypropylene Plastics Share Flipboard Email Print Hans-Peter Merten / Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Todd Johnson Science Expert B.S., Business Management, University of Colorado Boulder Todd Johnson has worked on the development, commercialization, and sales sides of the composites industry since 2004. He also writes about the industry. our editorial process Todd Johnson Updated February 04, 2020 The world of plastic is not a cut and dried one. There are around 45 different types of plastic and each one has its own properties and uses, from commercial to residential. Polypropylene is one type of plastic that is used for a number of different products, due to its wide variety of properties. Understanding the chemical properties, history, and advantages of this plastic can allow you to see the importance that this type of plastic has on your everyday life. What are the chemical properties of this plastic? Chemical Properties of Polypropylene Polypropylene is located between low-density polyethylene (LDPE) and high-density polyethylene (HDPE) on the crystallinity level. It is flexible and tough, especially when it is copolymerized with ethylene. This copolymerization allows this plastic to be used as an engineering plastic that is in a number of different products and uses. The flow rate is a measure of molecular weight and this determines how easily it will flow during processing. A higher MFR allows the polypropylene to fill the mold more easily. As the melt flow increases, some of the physical properties of the plastic decreases, however, such as impact strength. History of Polypropylene German chemist, Karl Rehn, and Giulio Natta first polymerized propylene to a crystalline isotactic polymer in March 1954. This discovery soon led to the commercial production of polypropylene starting in 1957. Others claimed the discovery, as often occurs when a general body of knowledge is used, and this litigation was not resolved until 1989. This very popular plastic is one that many different manufacturers use for a number of different products. What Polypropylene is Used For Polypropylene is used for a wide number of different products. Due to the resistance to fatigue, this means that it can be used on items that are going to have high stress, such as hinge mechanisms on water bottles and more. It is also used in manufacturing piping systems, as well as chairs, and in medical or laboratory use. The colorfastness means that it is also used in carpeting, rugs, and mats. Ropes, cable insulation, roofing membranes, storage boxes, disposable bottles, plastic pails, and other items are also made using this type of plastic. When you consider the impact of this plastic on your everyday use, you will see that it is one plastic that most people just cannot live without. PP plastics are also used in fiber-reinforced composites. Common trade names for FRP glass fiber reinforced polypropylene include Polystrand and Twintex. Polypropylene Advantages Polypropylene offers many different advantages. These advantages allow it to be used for a wide variety of different products and uses, from high heat to cold weather and more. What are some of these advantages? The low cost makes it budget-friendly for a wide number of usesHas a moderate strength and stabilityHas flexibility, which makes it easy to mold into different shapesColorfast, which means that any colors will stay bright and beautifulResistant to fatigue, which allows it to be used for things such as water bottle hinges and spoutsOffers good insulation for pipes, cables, and moreChemically resistant to most oils and solventsExcellent impact strengthLow coefficient of frictionExcellence moisture resistanceHigh-temperature resistance, which means it can be used in laboratories When you look at polypropylene, you can see that it has many different properties that explain its widespread use. From clothing to pipes to carpet and more, this type of plastic is one that is used in a number of different products. Understanding its importance will allow you to appreciate it to the fullest. Polypropylene is one plastic that can be used for products now and can be recycled into products for the future as well.