Kevlar is a unique polymer in that it is used for bulletproof vests and jackets. Polly 1122 tetrafluoroethylene also known as PTFE, which is a nonstick coating on frying pans as well as being used in bearings another low friction surfaces. Polychloroprene Etaene, often known as PVC, is used for windows and door frames, plastic hinges, and bottles. Polypropylene is used for bottle caps, plastic bottles, and plastic pipes. High-density polyethylene is used for drain pipes, water bottles, and containers. Polythene used for carrier bags and plastics. Here are some specific examples of polymers and their common uses. It's a long-term goal for many chemists is to develop more biodegradable plastics which would naturally break down in our environment. Some of this can be recycled to minimize the effects on our environment. However, the increased use of plastics in our homes leads to nearly one-quarter of all the solid waste being plastic. From simple packaging to complex structural building materials. The common name to synthetically made polymers is plastics which are used very frequently in our day-to-day lives. We'll focus the rest of this tutorial on synthetic polymers. There are a number of natural polymers in life such as rubber, and even in our own body we have natural polymers such as proteins, carbohydrates, and DNA to name just a few. As you now know, polymers are a long chain of organic molecules made by repeating monetary units. In this video, we'll explore in more detail some different polymers and their specific uses as well as the problems associated with polymers. In our previous videos we have explored how polymers are formed and equations for polymerization reactions. In block copolymers, more complex repeating structures are possible, for example AAABBBAAABBBAAA… Graft copolymers are created by attaching chains of a second type of monomer on the backbone chain of a first monomer type. In an alternating copolymer, each monomer is alternated with the other to form an ABABABA… pattern. If the two monomers are randomly ordered then the copolymer is, not surprisingly, referred to as a random copolymer. The four basic structures are random, alternating, block, and graft. If a chemist is synthesizing a polymer utilizing two distinct starting monomers there are several possible structures, as shown in the figure below. Next, we will look at how copolymers are classified. When building a polymer from two distinct monomers, those polymers are referred to as copolymers. Monomers do not have to be of a single atom type, but when referring to a specific monomer it is understood to be of the same composition structure. These polymers are nearly impossible to soften when heating without degrading the underlying polymer structure and are thus thermosetting polymers. Networked polymers are complex polymers that are heavily linked to form a complex network of three-dimensional linkages. This much stronger bond makes most crosslinked polymers thermosetting, with only a few exceptions to the rule: crosslinked polymers that happen to break their crosslinks at relatively low temperatures. So, unlike linear polymers which are held together by weaker van der Waals forces, crosslinked polymers are tied together via covalent bonding. The chains link from one backbone to another. Since the short chains do not bridge from one longer backbone to another, heat will typically break the bonds between the branched polymer chains and allow the polymer to be a thermoplastic, although there are some very complex branched polymers that resist this ‘melting’ and thus break up (becoming hard in the process) before softening, i.e., they are thermosetting.Ĭrosslinked polymers resemble ladders. Since these shorter chains can interfere with efficient packing of the polymers, branched polymers tend to be less dense than similar linear polymers. Upon cooling the bonds between the long chains reform, i.e., the polymer hardens.īranched polymers resemble linear polymers with the addition of shorter chains hanging from the spaghetti backbone. Heat breaks the bonds between the long chains allowing the chains to flow past each other, allowing the material to be remolded. Since these bonding types are relatively easy to break with heat, linear polymers are typically thermoplastic. The long chains are typically held together by the weaker van der Waals or hydrogen bonding. Linear polymers resemble ‘spaghetti’ with long chains.
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