Monday, December 30, 2019
The Many Uses of Plastics
Most modern plastics are based on organic chemicals that offer manufacturers a huge range of physical properties that is still growing. There was a time when anything made of plastic was considered to be of inferior quality, but those days are past. You are probably wearing plastic right now, maybe a polyester/cotton mix garment or even glasses or a watch with plastic components. The versatility of plastic materials comes from the ability to mold, laminate or shape them and to tailor them physically and chemically. There is a plastic suitable for almost any application. Plastics dont corrode, though they can degrade in UV, a component of sunlight, and can be affected by solvents. PVC plastic, for example, is soluble in acetone. Plastics in the Home There is a huge percentage of plastic in your television, your sound system, your cell phone, and your vacuum cleaner and probably plastic foam in your furniture. What are you walking on? Unless your floor covering is real wood, it probably has a synthetic/natural fiber blend like some of the clothes you wear. Take a look in the kitchen and you might see a plastic chair or bar stool seats, plastic countertops (acrylic composites), plastic linings (PTFE) in your nonstick cooking pans, and plastic plumbing in your water system. Now open your refrigerator. The food might be wrapped in PVC cling film, your yogurt is probably in plastic tubs, cheese in plastic wrap, and water and milk in blow-molded plastic containers. There are plastics now that prevent gas from escaping pressurized soda bottles, but cans and glass are still No. 1 for beer. (For some reason, guys dont like to drink beer from plastic.) When it comes to canned beer, though, you will find that the inside of the can is often lined with a plastic polymer. Plastics in Transport Trains, planes, and automobiles, even ships, satellites, and space stations, use plastics extensively. We used to build ships from wood and planes from string (hemp) and canvas (cotton/flax). We had to work with the materials that nature provided, but no moreââ¬âwe now design our own materials. Whatever mode of transport you pick, youll find plastic used extensively in: SeatingPanelingInstrument enclosuresSurface coverings Plastics are even combined with other materials as structural elements in all kinds of transport, even skateboards, rollerblades, and bicycles. Challenges for the Plastics Industry Its clear that modern life would be very different without plastics. However, challenges lie ahead. Because many plastics are so durable and dont corrode, they create considerable disposal problems. They arent good for the landfill, as many will persist for hundreds of years; when theyre incinerated, dangerous gases can be produced. Many supermarkets now give us one-use grocery bags; leave them in a cupboard long enough and all you will have left is dust because they are engineered to degrade. Perversely, some plastics can be cured (hardened) by UV, which shows how varied their formulas are. Additionally, because many plastics are based ultimately on crude oil, there is a continuous rise in the cost of raw materials that chemical engineers are trying to workaround. We now have biofuel for automobiles, and the feedstock for that fuel grows on the land. As this production increases, sustainable feedstock for the plastic industry will become more widely available. We are getting wiser, and now many plastics can be chemically, mechanically, or thermally recycled. We still must solve the disposal issue, which is being actively addressed through materials research, recycling policies, and enhanced public awareness.
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