Plastic Bags: What’s The Difference Between Degradable, Compostable and Biodegradable?

Plastic Bags: What’s The Difference Between Degradable, Compostable and Biodegradable?

It seems to be a common misconception that degradable or biodegradable bags are a suitable alternative to plastic bags, but they’re great in theory and environmentally destructive in reality. Recently, an enquiry into the threat of marine plastic pollution in Australia found that the degradable bag option is equally as bad for the environment as regular plastic bags.

The findings of the report stated that;


The inquiry also found that there is some serious confusion amongst the community surrounding the difference between bag types. It can be difficult to navigate the minefield of planet-friendly options, so here’s our handy guide to help you separate what’s truly eco from what to veto.

Traditional plastic bags

How are traditional plastic bags detrimental to our environment? Let me count the ways. Single-use plastic bags have an average life span of 12 minutes, and worldwide we are using 2 million of these every sixty seconds.

Polyethene bags are made from a non-renewable resource, and are incredibly harmful to the marine environment as they never biodegrade. Instead, they will simply break into smaller and smaller pieces over hundreds of years, inflicting untold amounts of damage to natural ecosystems.

Image: Troy Mayne

Biodegradable plastic bags

To put it simply, something is biodegradable when living things, like fungi or bacteria, can break it down. Biodegradable bags are made from plant-based materials like corn and wheat starch rather than petroleum. However when it comes to this kind of plastic, there are certain conditions required for the bag to begin to biodegrade.

Firstly, temperatures need to reach 50 degrees Celsius. Secondly, the bag needs to be exposed to UV light. In an oceanic environment, you’d be hard pressed to meet either of these criteria. Plus, if biodegradable bags are sent to landfill, they break down without oxygen to produce methane, a greenhouse gas with a warming capacity 21 times more powerful than carbon dioxide.

Degradable or ‘oxo-degradable’ plastic bags

Degradable items don’t have living organisms as a crucial part of the breakdown process. Degradable bags cannot be classed as biodegradable or compostable. Instead, chemical additives used in the plastic allow the bag to break down quicker than a standard plastic bag usually would.

Essentially bags touted as ‘degradable’ are definitely not beneficial, and can even be worse for the environment! Degradable bags that disintegrate just become tinier and tinier pieces of microplastic quicker, and still pose serious threats to marine life. Microplastics enter the food chain lower down, getting eaten by smaller species and then continuing to make their way up the food chain as these smaller species are consumed.

Professor Tony Underwood from the University of Sydney described degradable plastic bags as “not a solution to anything much, unless we are quite happy to shift it all into particle-sized plastics rather than plastic bag-sized plastic.”



Compostable plastic bags

The word ‘compostable’ is incredibly misleading for the average consumer. You’d think a bag labeled ‘compostable’ would mean you could throw it in your backyard compost alongside your fruit and vegie scraps, right? Wrong. Compostable bags biodegrade, but only under certain conditions.

Compostable bags need to be composted in a specific composting facility, of which there are very few of in Australia. Compostable bags are generally made from plant material that return to base organic components when processed by these facilities, but the problem lies in the fact there are thus far only 150 of these facilities Australia wide.

Can I recycle plastic bags?

Plastic bags, biodegradable, degradable and compostable bags cannot be placed in your standard recycling bin at home. They can severely interfere with the recycling process if they are.

However, your local supermarket may offer plastic bag recycling. Some supermarkets can also recycle ‘green bags’ that are torn or no longer used.


Polythene Calculations

Polythene Calculations

No need to work out all those awkward calculations and sizes, we are adding several different tools to help you order your polythene products easily and correctly.

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Merry Christmas

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Blown or Cast Stretchfilm

Blown or Cast Stretchfilm

various stretchfilms

Stretch film comes in varying gauges, colours and can be used in numerous applications. The main variable and starting point for stretch films is blown versus cast.

While I won’t bore you too much with the details behind how they are manufactured, here are the basics. Blown stretch film, or blown stretch wrap as it’s also known, is created by blowing heated resin out vertically into a bubble. The bubble is then transformed into rolls while it is cooled by the surrounding air. Cast stretch film, or cast stretch wrap as it’s also known, is created by feeding a sheet of heated resin along a rolling path with chilled rollers. The cooling solidifies the film, and it is made into large rolls.

So, now that you know how stretch wrap is produced, what do the difference in films provide you, the end user, in terms of features and benefits? I thought you would never ask.

Blown film is tougher and has less of a chance to puncture than cast. This occurs due to the slower cooling process, which allows the molecules in blown film to spread out as opposed to aligning in long lines like in cast. Blown film also has a higher level of cling (think Reynolds Wrap) than cast, making it stick to itself easier.

So, why would anyone use cast film? Cast stretch wrap has a clear, glossy finish allowing RFID and other scanning technology to be used with it while blown is hazy and dull. Cast stretch film unwinds much quieter than blown. It is also easier to stretch and control the gauge with cast film.

As you can see, both films have their benefits and hindrances.

So, which stretch film fits your application?

Factors to keep in mind include:

  • What type of machine is being used, if not applied by hand?
  • What kind of load is being wrapped?
  • Where does your skid go after leaving your dock?
  • How many variants of load does your facility wrap?

Does your distributor ask you these types of questions and provide solutions based off of your answers?

If you answered no, it’s time for a free needs analysis from the industrial packaging experts at Lynx Polythene. Our solutions providers will ask you the above questions and more and perform tests to determine just how much film you are using and how much it is costing you per application. Having troubles with punctures or products getting damaged? That means it’s time to reevaluate your film type and usage.

If you are purchasing films based on the one with the cheapest price per roll, you may be surprised what kind of information and insight can be gained by going through our process.

How To Use Polythene Layflat Tubing

How To Use Polythene Layflat Tubing

Polythene layflat tubing has to be one of the most exciting pieces of comprehensive polythene we produce. Endless amounts of made to fit bags on a single roll. Easy to use and easy to store. Who could ask for more?

With the possibilities of polythene layflat tubing seemingly endless, we thought we’d take a look at how exactly you can use polythene layflat tubing and what it can do for you.

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Welcome To Our Brand New Blog!

Welcome To Our Brand New Blog!


First of all hello and welcome to all of our new and existing customers!

We’re very excited about our new blog and can’t wait to share with you our passion for everything polythene!

Before we jump head long into the ins and outs of our industry, of the Top Ten’s, Do’s and Don’ts, History and Future of polythene  materials, equipments and tools; we thought we’d tell you a little bit about ourselves.

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