What Are Polymers? And Other Plastic FAQs You've Always Wanted to Ask

What Are Polymers? And Other Plastic FAQs You’ve Always Wanted to Ask

By AAA Polymer | Plastics Recycling

Feb 26

Whether you're new to the plastics recycling industry or have been around the block a time or two, you've more than likely asked 'What are polymers?' In fact, you've probably had many questions about plastic polymers, stretch film, and can liners. If so, you've come to the right place!

Since 1974, AAA Polymer has been committed to all things plastic, stretch film, plastic recycling, plastic can liners, and more. If you have questions or a problem, we've made it our business to provide cost-effective solutions.

Don't hesitate to reach out to us today. In the meantime, let's answer the question "What are polymers" along with a few other FAQs we regularly receive.

What Are Polymers?  

A polymer is a chemical compound made up of identical molecular repeating units. Plastic material is a polymer, and it's usually modified with different additives to give plastic the desired qualities and attributes. The majority of elastomers/rubbers and polymers are composed of carbon-based molecules, which means they are organic. 

These materials are created from oil-based, simple raw materials. These simple monomers are connected through a process known as polymerization, which involves long chains being made up of repeated, identical units.

What Polymers Are Plastic Bags Made From? 

In the case of can liners and plastic bags, the repeating units are either ethene or ethylene. Long chains of carbon atoms are formed in the process of ethylene molecules being polymerized to create the very common polyethylene. Several different types of polyethylene can be created from ethylene. However, plastic bags are typically made from one of three different types:

  • High Density Polyethylene (HDPE)
  • Low Density Polyethylene (LDPE)
  • Linear Low Density Polyethylene (LLDPE)

What's the Difference Between HDPE vs LDPE vs LLDPE? 

The crinkly grocery bags are from HDPE. The glossy, thick shopping bags you'd receive from the mall are made from LLDPE. These can also resemble the common household trash bag. LDPE is used to create the clear garment bags from the dry cleaner as well as stretch films and stretch wraps

The primary difference between these three can liner materials has everything to do with the polymer chain branching. LDPE chains are unbranched, while LLDPE and HDPE are made up of linear, unbranched chains of polymers. 

How Does Polymer Branching Affect Bag Characteristics? 

As you can imagine, the branching of the polymer plays a central role in the physical properties of the material, including crystallinity and tensile strength. The more branched a material is, the lower its crystallinity and tensile strength, which is why dry cleaner garment bags are relatively flimsy and weak. 

These bags are created from a highly-branched LDPE. However, it's important to understand can liners can be made from all three materials, and each type of can liner can be effectively used efficiently in different applications. In fact, businesses can save thousands by switching to the right can liner for the job. 

How Are Stretch Films Different from Plastic Bags?  

While stretch film and stretch wraps can be made from several polymers, the most common are Linear Low Density Polyethylene and Low Density Polyethylene. These are the same elastomers used in the manufacturing of certain types of plastic bags. 

However, stretch films are engineered to be a highly stretchable and reliable material that keeps products tightly bound. To achieve this goal, there may be additives added to the LLDPE or LDPE, but the qualities of the film depend on how it is manufactured: cast extrusion process or blown extrusion process

What Is the Cast Extrusion Manufacturing Process for Film?

The cast extrusion process involves a molten resin being fed through a narrow slot die. Once it passes through the die, the resin is quickly passed over a chilled roller, which turns the molten resin back to a solid. Then, tension rollers work to move the wrap to the winding and slitting stations. This manufacturing process causes cast stretch wrap to have unique characteristics: 

  • High transparency
  • A very quiet unwind
  • Uniform thickness
  • No thickness limits
  • Outstanding barrier for gases, moisture, and aromas

What Is the Blown Extrusion Manufacturing Process for Film? 

With the blown film extrusion process, melted plastic is extruded through an annular slit die to create a thinly-walled tube. Air is then blown into the tube to fill it like a balloon. An air ring blows onto the top of the film to cool it, which allows the film to be more resilient and robust. The characteristics of film created through this process include:

  • Excellent puncture resistance
  • Remarkable durability and maximum toughness
  • Less manufacturing scrap
  • A high level of cling

Which Plastic Polymers Are Recyclable? 

At AAA Polymer, we help warehouses and distribution centers create stretch film and stretch wrap recycling programs. Our programs are proven to help these facilities pad their bottom line and create savings. While a number of plastic materials are recyclable, we specifically help facilities with: 

How Can Commercial Recycling Save Facilities Money? 

Because there is a cost associated with hauling trash away, most businesses pay a fixed charge every time a trash bin is picked up. When you remove plastic scraps from your waste stream, you will reduce the number of required pickups, which equals real savings. In addition to the pickup, the disposal site levies a per-ton tipping fee, such as: 

  • The tipping fees in New York can be as low as $49.50 up to $102.00.
  • The tipping fees in New Jersey can be as low as $44.31 up to $96.00.
  • The tipping fees in Massachusetts can be as low as $72.00 up to $100.

Your tipping fee for disposing of 250,000 lbs (125 tons) of stretch film in the New York area at an average of $86.30 per ton would be $9,000 (125 tons x $86.30 per ton). As you can see, removing recyclable plastic materials from your waste stream can result in real savings. 

Contact AAA Polymer

At AAA Polymer, we are your plastic experts. If you have questions or a problem, we have answers. 

Contact AAA Polymer today for tailored solutions that make a difference.

About the Author

AAA Polymer, Inc. was founded in 1974, as a plastic resin and material trading company with an innovative vision to create a company to provide plastic recycling services for industrial/commercial businesses. If you have any questions, we're here for you. Just call us at 718.389.2498.

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