From the perspective of the average person, all plastics might seem the same. Some of them are thicker, some of them are thinner, but they do all of the same things. While it is true that all plastics have similar properties, they are a lot more diverse than most would guess. There are thousands of different plastics in the world, and all of them have specific uses for which they were created. With that in mind, let’s take a quick look at three of the most common plastics. We will examine how they differ, how they are similar, where they are strong, and where they are weak.
The Qualities Of PVC
PVC has been around since 1872, although it wasn’t mass-produced until the 1920s. It is the go-to material for plumbers, and there are many good reasons for that fact. This is easily one of the most versatile plastics around, as it is found is a huge variety of products. It can be found in many construction applications due to its superior strength. It’s also easy to sterilize, so you can find a lot of PVC products in the medical field. Believe it or not, they even make clothing out of PVC fibers.
Under normal circumstances, it is white in color and somewhat brittle, but PVC is normally mixed with plasticizers that help to counter this problem. Through the use of various plasticizers, PVC can be made very stiff or very flexible, depending on what the situation demands. In some cases, it can even be flexible enough to be used as a rubber substitute.
PVC is heavily standardized, which is a great advantage in the consistency department. It can be purchased in a variety of grades, referred to as “schedules.” Although there are many differences between these schedules, this is mainly a measure of their strength. The higher-level pipe will tend to have thicker walls, denser material, and a different color to separate it from the rest.
So, PVC offers a lot of good points. For one thing, it’s very strong. It is denser than most plastics and has a specific gravity of about 14. If you don’t know what “specific gravity” means, just understand that it is a general measurement of density. While some other plastics are easily deformed, this one is springy. This springiness can make it useful for a variety of alternative purposes. For instance, some people have even made bows from bent lengths of PVC pipe.
Not only is PVC very hard and strong, but it’s also quite cheap. Because of its frequent use in home plumbing and ground conduits, PVC is manufactured in huge amounts. As in most instances, that adds up to a lower cost. This is partly due to the fact that PVC is relatively easy to melt, mold, and pour. In spite of this, PVC is much more resistant to flame than most plastics. It also resists chemical degradation like few other things on earth.
PVC is often used to provide a protective covering for electrical conduits. It is ideal for this purpose because of its high insulation factor. It does a good job of shielding the electricity and keeping out moisture. The same properties that allow it to contain water will allow it to repel water.
PVC does have certain problems and weaknesses, as well. For one thing, it doesn’t deal well with extreme temperatures. During the cold winter months, the material will expand and become more brittle. If your pipes should happen to freeze on a particularly cold night, the problem becomes even worse, and the pipes are likely to burst. PVC is also not particularly eco-friendly and may contribute to several environmental problems.
Polyolefin plastics, also known as polyalkene plastics, are polymers of a substance called olefin. There are many subgroupings of this kind of plastic, including polypropylene, HDPE, LDPE, LLDPE, and EPDM. It should be mentioned that polyethylene is a type of polyolefin, but it is distinct enough to warrant its own section, and that is why it will be considered separately.
In general, polyolefin plastics are not the strongest around. However, they are extremely versatile and easy to use. These kinds of plastics are often used for rotational molding, which is a very fascinating process in itself. The plastic is injected into a mold that consists of two halves. After being pressed together, the molds are then rotated so that the plastic will disperse evenly. This ensures a uniform and smooth result. It is exceptionally easy to use polyolefin plastics for this process.
These kinds of plastics are exceptionally popular in the medical industry. In fact, polyolefins are the most common types of plastics for use in medical devices. A lot of doctors recommend this plastic, and they have several key reasons for doing so. For one thing, this kind of plastic has very little taste or odor. This makes it the perfect material for tongue depressors, thermometer covers, and anything else that might go into a patient’s mouth.
More importantly, polyolefins are probably the safest plastics for general use. Some people are allergic to things like latex and even silicone. Nylon-based materials are great but far too expensive for disposable items. PVC is great overall, but there are some serious toxicity concerns that make it impractical for use in a medical setting. Standard polyethylene is also suitable for medical use, but it doesn’t tend to be quite as durable.
In terms of strength, polyolefin plastics can range throughout the entire spectrum. They can be as hard as you want or as soft as you want. This is why we say that it’s the most versatile plastic out there. In fact, you can even convert one sort of polyolefine to another kind. One thing that contributes to the versatility of this material is its ease of melting. Rather than attempting to melt the plastic itself, they usually mix this plastic with a boiling hot solvent to create a liquid mush. This mush is then injected into molds for easy processing.
From an environmental perspective, this kind of plastic is obviously the superior choice. As far as we can tell, there is no reason to be concerned about the effects that this plastic could have on the natural world. While there is always the chance that science has missed something, there is little doubt that these kinds of plastics are nowhere near as toxic as most of the alternatives. Not only that, but they help the environment in another way.
Anything that reduces human waste is bound to help the environment. As such, polyolefin plastics offer a great way to reduce the impact of our garbage on the world. Because they do not flex and crack in extreme temperatures like some other plastics, they will generally last a lot longer. It would seem that they are the better choice for outdoor use, though they are not as cheap as PVC-based plastics. Still, a longer lifespan equals less trash and less use of nonrenewable resources.
The Qualities Of Polyethylene
Polyethylene has the distinction of being the most popular plastic in the world. It is commonly used for so many things that it would be ridiculous to try and name them all. Of all the commercially-used polymer plastics, this one has the simplest molecular structure. This might explain why it is so cheap and simple to manufacture. Being one of the polyolefins, it is incredibly versatile.
Overall, polyethylene is not particularly strong. That’s why you often see it used for low-durability applications like grocery bags, small packages, single-use food bags, and other such disposables. However, there is more than one kind of polyethylene. One type of polyethylene is so strong that it can be used in the making of bulletproof vests. When it comes to durability, you couldn’t ask for anything better than that!
Polyethylene has replaced a lot of materials that were once in common use. Some of these applications might surprise you. For instance, Polyethylene floors are now being used to replace traditional ice rinks. If made to certain specifications, a polyethylene floor can provide the same kind of experience as an ice risk, but without any of the risks and complications that come from the old-fashioned method. When you think about it, installing a plastic surface is a lot easier than maintaining a huge chunk of ice for many hours at a time!
Polyethylene has a naturally waxy consistency, and this makes it very good for moisture resistance. For instance, you might be installing a layer of plastic underneath your roof shingles to serve as an additional barrier against moisture. A sheet of polyethylene would be great for this purpose. If you happen to be making a rain collector, you might also find PE to be the best choice. That waxy outer layer makes water bead up easily so that it flows away to the lowest point.
When it comes to flexibility, polyethylene cannot be beaten. In terms of ductility, it gets high marks. There is a slight difference between flexibility and ductility, and this should be noted. Flexibility refers to the ability of an object to bend without breaking. Ductility refers to the ability of an object to be stretched thin without losing strength. Most substances will become very weak when stretched thin, but polyethylene does not. Therefore, it is a great material for small objects like thin rubber tubing.
On top of all this, PE also tends to make a great electrical insulator. One of the first important uses for this plastic came during World War 2 when it was used to insulate radar cables that would otherwise have been more susceptible to damage. As a substance, PE has been known to science for a very long time, but it wasn’t until the early 1930’s that it began to emerge in the huge variety of forms that we know today.
PE can be made with a wide range of densities ranging from high to low, so its versatility is right up there with the other polyolefins. It can also be melted in more than one way. Depending on how you use it, PE can function as a thermoplastic (heat-molded) or a thermoset plastic (cooled from a liquid substance).
As you can see, there are many important differences between these three plastics. Yes, all three of them can be used for similar purposes, but there is always the question of how well-suited they are for a particular job.
For instance, PVC is obviously the best choice when repairing your home plumbing. For one thing, you want to match your existing system, which is probably made of PVC. For another thing, it’s very cheap. However, let’s say you are making plastic bowls, plates, or utensils. These things will be in direct contact with food, and PVC would be a terrible choice for that. There are some toxicity issues that could cause people to get sick. Not only that, but it might also impart a terrible plastic taste to the food.
So, that’s just one example of how a certain kind of plastic can be excellent for one purpose and terrible for another! If you have found our wisdom to be helpful, we hope that you will fill out the contact form below to receive more from our team of experts.