Being Responsible with Plastics
For many people who use plastics, the simple answer to being responsible is usually just to throw the plastic into a recycling bin. However, this is not always the case.
Newsflash: not all plastics are recyclable.
This is due to the fact that plastics are produced by different materials, some of which make them non-recyclable.
Plastics are sorted into seven categories based on their materials as well as the safety and biodegradability of the plastic. These categories are typically denoted by numbers within the recycling symbol on the bottom of plastic products, known as a resin identification code.
The types of plastics including Polyethylene Terephthalate (PET #1), High Density Polyethylene (HDPE #2), Polyvinyl Chloride (PVC #3), Low-Density Polyethylene (LDPE #4), Polypropylene (PP #5), Polystyrene (PS #6), and Miscellaneous Plastics (#7).
For those of you who really want to know all about the plastics around us, this article is for you. However, if you are looking for the short and sweet run down on what type of plastic is recyclable, there will be a summary list at the end!
Hopefully, this article will serve you as a guide to knowing what you can recycle as well as influence you to reconsider your use of non-recyclable plastics!
Polyethylene Terephthalate
The first plastic, denoted by the number one in the recycling symbol, is polyethylene terephthalate. This plastic is considered to be the most easily recyclable plastic type. Due to this, PET plastics are also the most recycled plastic type around the globe (PETRA).
Created first in the mid-1940s, PET is made up of ethylene glycol and terephthalic acid. Unfortunately, the materials are petroleum based thus raising several concerns regarding environmental issues such as CO2 emissions.
This type of plastic is most commonly seen in single-use plastics: water bottles, soda bottles, shampoo containers, and many other plastic containers for food as well as hygiene products.
However, when PET crystalizes it , “starts to become opaque, more rigid and less flexible (PETRA).” When this occurs, polyethylene terephthalate is instead used for containers and trays that are microwave safe!
PET is also known as polyester which is a common fabric for clothing. Polyester is found in over 60% of clothing in stores today (TheRobinReport) and is common in especially in workout clothes! The repurposing of clothes via thrift stores and donations is also an important form of recycling- we will explore this soon!
PET plastics are all around us, but are also a big source of visible plastic pollution in our world today. Just remember that #1 plastics are recyclable- so recycle that water bottle!
High Density Polyethylene
Here is another easily recognizable and recyclable plastic! High density polyethylene, known as plastic type 2, acts as an important material in many different products so lets take a look!
Structure
HDPE is made from the petroleum derivative ethylene, which is a hydrocarbon molecule with a 2:4 ratio. HDPE is considered to be a thermoplastic polymer that is, “easily meltable and moldable, corrosion resistant, and strong (ACME Plastics).”
However, as it is made from petroleum derivatives, it once again poses environmental problems.
Uses
The most common use of high density polyethylene is in plastic bottles, milk jugs, and bleach bottles. It can also be used in less common plastics such as snowboards, 3-D printing materials, and plastic surgery! (ACME Plastics)
Recyclable?
Again, this plastic is easily recyclable so, if you see the number two, toss it in the recycling bin!
Polyvinyl Chloride
Next, we have a well-known plastic in the plumbing as well as creative engineering world: PVC! This plastic has a number 3 resin identification code.
Structure
PVC materials are rarely recycled for two main reasons. First, PVC is mainly used in construction material with a lifetime of about 50 years so it’s recycling is not as visible as single-use plastics.
However, they are also not typically recycled due to the problems they cause during the recycling process. PVC has a high chlorine content as well as hazardous additives which means they must be separated from the typical recycling stream (EcoMENA). So these materials are recyclable but you must recycle them in the proper, less traditional, way!
There are also two basic types of PVC plastics- flexible and rigid. Flexible PVC, or PVC-P, has” a lower crystallinity making it much clearer and flexible” while rigid PVC is “stiff and cost effective with high resistance (Omnexus).”
Uses
PVC plastics are typically found in construction materials such as PVC piping, wires and cable insulation, flooring, medical devices, and windows.
Recyclable?
Chances are that you will not encounter much PVC, unless you enter the construction industry or experiment in home plumbing. Just remember, recycling PVC materials is a bit different so do some research as to where you can properly dispose of your waste!
Low-Density Polyethylene
Now we dive into another type of polyethylene plastic type yet this time the low-density type. As a number 4 resin identification code, this plastic poses a lot more trouble than the previous plastics.
Structure
Like its high density counterpart, LDPE is also made from the petroleum derivative ethylene, a hydrocarbon molecule with a 2:4 ratio. However, LDPE’s polymers differ from HDPE’s because LDPE polymers, “have branches and don’t stack as snugly (Container and Packaging).”
As a result of these non-conforming polymers, LDPE plastics are flexible and lightweight with a low temperature resistance.
Once again, LDPE plastics are created with products stemming from the petroleum industry so it poses the same environmental problems as HDPE and polyethylene terephthalate plastics.
Uses
LDPEs are found in extremely familiar and common items as well as less common yet necessary items (for certain groups of people). LDPE plastic materials are found in plastic bags, containers, orthotic applications, and prosthetics.
Recyclable?
In the case of orthotic applications and prosthetics, you probably will not encounter the situation of figuring out whether they are recyclable or not.
However, when in comes to plastic bags and containers, you should really know your stuff.
Rigid LDPE plastics, such as containers, are in fact allowed to be recycled in the regular bin so get used to tossing those number four bottles in!
Yet, when you encounter plastic bags, it gets much more complicated. Just know that you can put the bags in the regular bin, but that does not mean you should.
Plastic bags pose problems for typical recycling plants, as they will catch and snag within the processors and sorters. As a result of this, many plants will not recycle the bags thus discarding them, improperly, elsewhere.
Don’t fret though- they can be recycled just in a different format! Many local grocery stores have setup plastic bag recycling bins in their store! As long as the bags are clean and dry, the bags will be recycled properly from these bins!
Polypropylene
Here we have a multi-purpose plastic that has integrated its way into our homes and lives. With a resin identification code number 5, polypropylene is a useful plastic with a complicated recycling process.
Structure
Polypropylene is once again a hydrocarbon-based plastic with a ratio of three carbons to six hydrogen (Container and Packaging). These hydrocarbons are known as propene, or propylene, and their chains are linked together in order to form plastic number 5!
Polypropylene is considered to be a semi-rigid plastic that is, “extremely resistant to heat, chemicals, and fatigue (AZO CleanTech).” PP also includes toxic additives such as lead and calcium which poses problems for its recycling.
Uses
PP plastic material is found in items such as clear film packaging (think Saran Wrap), lab equipment, bottle caps, and drinking straws. Due to its insulation properties, PP plastic material is also found in car parts, carpet fibers, and other construction materials.
Recyclable?
According to AZO CleanTech, “while PP is easily among the most popular plastic packaging materials in the world, only around 1% is recycled.” This is a serious issue so let us look at why this statistic exists.
PP plastics have to go through a five-step recycling process, which is consider time-consuming and expensive by recycling plants. This, along with people’s general misunderstanding of plastic number 5’s recyclable qualities, contribute to this scary statistic.
However, when PP plastic materials are recycled, they can be recycled and reused in so many different ways! This leads to a shrinking dependency on oil and gas for new plastic production!
Polystyrene
Finally, the end of the plastic hierarchy: polystyrene. I have to admit, this is the least favorable of all the plastics due to its composition and non-recyclable nature. Last but not least, here is the breakdown of plastic resin number 6.
Structure
Once again, we have a plastic formed from hydrocarbon monomers! This time it is an eight Carbon to eight Hydrogen ratio thus utilizing the hydrocarbon known as styrene.
As we have mentioned countless times, the use of hydrocarbons means the use of oil and gas which contribute to environmental issues.
Polystyrene is used either in a solid form or foamed, expanded, form. The two forms provide different pros and cons thus used in making different products.
Uses
After reading this, you will realize that expanded polystyrene is actually a huge part of your life. Its main two products are red solo cups and styrofoam containers or packaging materials. However, it can also be used to make surfboards (it’s already wet suit season!) and car parts.
Solid polystyrene is found in products such as non-styrofoam yet still polystyrene packaging and lab equipment (Chemical Safety Facts).
Recyclable?
As of right now, polystyrene is not accepted at curbside recycling facilities. This fact makes a huge case for working towards decreasing our use of polystyrene single-use plastics!
Polystyrene single-use plastics have a 500 year decomposing period. That means that styrofoam container you used for takeout last week will be on this earth six times longer than the average human life span, which is 79 years.
All in all, polystyrene is the least recyclable plastic so avoid using it!
What You Can Do
Key takeaway: Remember, next time you are about to use plastics, to consider whether that plastic type is recyclable.
Recall that types 1, 2, and 3 are easily recyclable! Toss that plastic into the bin!
Remember that type 4 and 5 can be recycled but by different means so research where you can dispose of them properly!
Finally, try your absolute best to not use type 6. These plastics are rarely able to be recycled and will plague our earth for hundreds of years.
When it comes to type seven, you will have to do your own research as there are many miscellaneous plastics.
However, the greatest thing you can do is not use plastics at all! Use plastic substitutions such as metal/bamboo straws in place of plastic number 5, cloth bags in place of plastic number 4, and paper/glass plates and cups instead of plastic 6!
I know this was a heavy article, but you will end up thanking yourself when you don’t walk outside to find improperly disposed plastics everywhere!
Broaden your World (Sources)
Container and Packaging – Overview
Polyester in the Fashion Industry
Comprehensive Guide on Polyvinyl Chloride (PVC)
Recycling of PVC – Prospects and Challenges
Highlights of Low-Density Polyethylene
All you need to know about plastic bag recycling
AZO Clean Tech – Polypropylene
Everything you need to know about Polypropylene Plastic
Chemical Safety Facts – Polystyrene
Wow this is really informative! I knew there are different types of plastic and not all are recyclable but I really liked how you organized this and went to detail about each type.
This is very interesting and informative, I had always wondered what those numbers were for! Your explanations were easy to follow and I like that you gave advice/a solution at the end. The organization is great and this is definitely a great topic for a blog.