Technology Comparison
The marketplace offers four types of products: oxo-degradables, corn based plastics, bio-resins, and biodegradable plastic additives. These products offer different approaches to addressing the problem of plastic waste, but some solutions aren’t as effective as others. One thing is clear: BioSphere remains superior.
Oxo-degradation occurs when minerals of stearates are placed within a structure or litter environment where heat, light, air, and mechanical forces cause the plastic to break into small pieces. These pieces are not plastic, but rather diols, which are smaller molecular chains of plastic that have a lower molecular weight than plastic polymers. Diols can be regulated as per California Prop 65.
After breaking down into diols, reducing the overall molecular weight and visual product to smaller and smaller polymer chains, oxo-degradable products will further break down into CH4. This is then followed by a breakdown into Co2, then to Biomass, and finally into very small chains of stearates.
These products, when broken down into diols, allow bacteria and fungus to produce a saliva-like product to dissolve the diol. This occurs over a very long period of time because of the diol’s structure. The exact period of time is hard to define, as many companies are focused on reducing molecular weight and visual characteristics of plastic products. As such, it is very hard to tell how long plastic products remain in a landfill. Oxo-degradable plastic additives also require UV light to reduce the polymer chain prior to being placed into a landfill. Without this step, oxo-degradable additives are essentially useless when disposed of in landfills.
Overall, the combination of heat, air, and UV light required for this breakdown process makes it very hard for oxo-degradable additives to break down in a landfill. Because of this, it is not considered a fully biodegradable plastic solution.
Corn-based plastics (polylactic acid or PLA) are plastic substitutes made from fermented corn starch. PLA is used by a wide variety of manufacturers around the world.
Corn-based plastics are useful when placed into an industrial compost facility. They require a temperature of 140 degrees, most composting facilities operate at 110-150 degrees. Because of this, it is very hard for these plastics to decompose under normal composting facilities – This is why it is required to be placed in industrial compost facilities.
The problem with PLA is that the running temperatures needed to form most common applications require different uses of additives that negate the composting credentials of PLA. One can combine the PLA matrix with other bio-resins to achieve a more robust biodegradable product that withstands moisture and higher heat in ambient environments. This, however, slows the biodegradation rate by multiple times. Additionally, PLA utilizes large amounts of energy to produce and creates significant CO2 and N2O release into the environment when manufacturing due to fertilizers and pesticides. You can view white papers and other documents on how PLA hydrolyzes on our page is PLA compostable and biodegradable.
Most bio-resins are made with organic materials such as sugar and algae. Many organizations utilize PHA, PLA, and other bio-resins in the market. The core technology of bio-resins involves turning sugars into resins to make products. PHA utilizes microorganisms to do the work to turn biomass into a resin that then can make bioplastics.
Different bio-resins have different decomposition processes, including the time it takes to decompose. Certain testing standards have been developed to test these bio-resins, including the ASTM D6400, that are specific to industrial composting and not commercial composting or home composting conditions. All compost facilities have oxygen so certain kinds of fungus can grow.
New reports also show that bio-resin technology creates N2O, which is 310 times more potent than CO2. Due to these problems, the ozone depletion of bio-resins is at the top of the list above synthetic based polymers. This creates a problem for the environmental claims behind bio-resins as their base market is replacing PS, PP and PE. If you are creating a final product and want a low Life Cycle Assessment to the earth, compostable plastic is the worst for ozone depletion according to The University of Pittsburgh.
Bio-resin technology is considered degradable—not biodegradable—for industrial compost facilities.
Bio-additives are surface dissolving products that allow microbes to dissolve the surface of products by reducing the weight and shape of the plastic over time.
Molecular weight determines the speed of biodegradation for your product. The higher molecular weight of a product, the slower the biodegradation rate. Mixing bio-additives that are not consistent with your base resin will also slow your biodegradation rate for many reasons but mainly due to homogenous mixture of the plastic. Inexpensive carrier resins from the bio-additive suppliers or a homopolymer carrier resin will also slow your biodegradation.
Each polymer has a set of microbes that secrete enzymes for that plastic. Some microbes also secrete enzymes that consume different plastics. For example, some polystyrene microbes secrete enzymes that work on polyethylene. Some companies sell numerous products for individual resin types, but this is mainly for processing purposes. It is not designed for biodegradation at optimal rates, according to our independent testing of these products. Biodegradation of each product will work differently. Most will compare to one another after 30-40 weeks of biodegrading at the same rate, but each has different optimal times.
When secreting their enzymes, microbes have a tough time breaking certain bonds within the polymer chain on their own. Bio-additives allow microbes to work together to break down a product. Bio-additives also make plastic products hydrophilic, allowing microbes to use the biodegradable additive compounds to dissolve the plastic and turn it into dirt. The microbes are only able to eat from the surface of the plastic and not from the middle of the plastic, causing a slower decomposition time of the plastic.
Many biodegradable additive companies sell their products worldwide, these biodegradable plastic additive companies test their products using the testing method ASTM D5511 or ASTM D5526. This testing method is for environments with no oxygen (a landfill environment). Bio-additives are useful in these environments. Bio-additives allow the bacteria and fungus to dissolve the plastic layer by layer. This makes the plastic product maintain its original shape, rather than break into pieces. This reduces the weight of the plastic much more easily than oxo-degradable plastics.
While bio-additives do work very well, the surface area of the plastic is generally kept the same in most cases. We do however find that pits or holes on the surface may slightly increase the biodegradation, though it still does not allow the microbes to fully dwell within the plastic structure itself. This explains why most items after testing still maintain their form and shape.
The BioSphere Difference
BioSphere has been designed to overcome the hurdles that other biodegradable technologies face, and offers a valuable cost difference. Unlike other biodegradable plastic additives, Biosphere allows the microbes in both aerobic and anaerobic environments to consume plastic from deep within—not just on the surface—and works much faster than other technologies.
Compared to other options, BioSphere’s biodegradable additive is more affordable—and the technology is superior.
Comparing Technologies
| Specification | BioSphere | Oxo-Degradable | BioResins | Biodegradable Additives |
|---|---|---|---|---|
| Biodegradable in Landfill | Yes | No | Some | Some |
| Biodegradable in Compost | Yes | No | Yes | Some |
| Compostable ASTM D6400 | No | No | Some | No |
| Fragments if Littered | No | Yes | No | No |
| SASO Approved | Not at this time | Yes | No | No |
| Compatible with Recycling | Yes | No | No | Yes |
| ASTM D5511-12 | Yes | No | No | Yes |
| ASTM D5526-12 | Yes | No | No | Yes |
| ASTM D5338-12 | Yes | No | Yes | Some |
| Special Storage Needed | No | Yes | Yes | Yes |
| Indefinite Shelf Life | Yes | Ni | No | No |
| Degraded by Light-Heat-Moisture-Stress | No | Yes | Yes | No |
| Fragments During Degradation | No | Yes | Yes | No |
| Degradation Begins After Manufacturing | No | Yes | No | No |
| Thickness Needs to be Modified | No | Yes | Yes | No |
| UV Inhibitors needed | No | Yes | No | No |
| Can be Processed with Conventional Equipment | Yes | Yes | No | Some |
| Polystyrene | Yes | Some | Some | Some |
| Polyethylene | Yes | Yes | Yes | Yes |
| Polypropylene Injected Molded | Yes | Some | Yes | Some |
| Polypropylene | Yes | Yes | Yes | Yes |
| BOPP | Yes | No | Yes | Some |
| PET | Yes | No | Some | Some |
| APET | Yes | No | No | Some |
| Major Resin Types | Yes | No | No | Some |
| Liquid Form | Yes | No | No | Some |
| Powder Form | Yes | No | No | No |
| Metal Oxides | No | Yes | No | Some |
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