Biobased Content

1. What is the biobased content of plastics?
2. Which feedstocks are used to derive biobased plastics?
3. What is the threshold value of biobased content present in a bioplastic?
4. Which certifications and labels govern biobased plastics?
5. What are the biobased content values for several plastics?

Sustainability Path #1 — Use Materials of Bio-based Origin

➤ Determining Bio-based Content Biodegradability of Plastics Mass Balance Approach in the Plastics Industry Polylactic Acid (PLA): How to select the right grade? Polyhydroxyalkanoates (PHAs): How to select the right grade?

What is the biobased content of plastics?

The biobased content of plastics is defined as the percentage of renewable carbon (i.e., of vegetal origin) over the total carbon content of the material considered biobased. It is calculated using the below formula.


Biobased plastic is a class of plastics that contain organic carbon of renewable origin in part or whole. They are derived from plant biomass, like:

• agricultural crops and residues
• marine and forestry materials
• bio-waste
• algae, fungi, etc.

The plant biomass could have undergone physical, chemical, or biological treatment.

Which feedstocks are used to derive biobased plastics?

Biobased plastic feedstocks are raw materials derived from renewable biological sources that can be used to produce plastics. These feedstocks are seen as more sustainable alternatives to traditional petroleum-based plastics because they are made from renewable resources. Mentioned below are some examples of biobased feedstocks used by the plastic manufacturers today.


The table below shows the examples of bioplastics produced from the above biobased feedstocks.

Feedstocks / Bioplastics	Sugarcane	Sugarbeet	Corn	Potato	Wheat	Castor seed oil	Biomass
PLA	✓	✓	✓	✓	✓
PHAs	✓	✓	✓	✓	✓
Bio-PBS (A)	✓	✓	✓	✓	✓
Bio-PET	✓	✓
PEF	✓	✓	✓	✓	✓
Bio-PP	✓	✓	✓	✓	✓
Bio-PAs						✓
PTT	✓	✓	✓	✓	✓
Starch Blends			✓	✓	✓
PBAT							✓
PBS							✓

Biobased vs. Biodegradable - What is the difference?

The term bioplastics is often used for a group of materials based on biomass or the biodegradable character of plastics. But, the biobased & biodegradable aspects of plastics are not synonymous. Biobased plastics emphasize the source of the plastic, which is derived from renewable resources, while biodegradable plastics focus on the material's ability to break down naturally.

Plastic Grade	Petrochemical-derived	Partly Biobased	Biobased
Non-biodegradable	Polyethylene (PE) Polypropylene (PP) Polyethylene terephthalate (PET) Polystyrene (PS) Polyvinylchloride (PVC)	Bio-PET Polytrimethylene terephthalate (PTT)	Bio-PET Bio-PE Bio-PP Bio-PA Polyethylene furanoate (PEF)
Biodegradable	Polybutylene adipate terephthalate (PBAT) Polycaprolactone (PCL) Polyvinyl alcohol (PVA) Polybutylene succinate adipic acid (PBSA)	Starch blends	Polylactic acid (PLA) Polyhydroxyalkanoates (PHA)

The image below shows the pathways that different biobased polymers undergo, right from their raw material used to the final plastic obtained.

Key benefits of bioplastics

• Bioplastics reduce the demand for fossil resources. They contribute to the increased use of natural resources.
• They can be recycled like the traditional plastics. Hence, they reduce the amount of waste that goes to landfills.
• They contribute to lowering greenhouse gas emissions.
• Unlike traditional plastics, bioplastics can be broken down by microorganisms. Thus they promote biodegradability.

What is the threshold value of biobased content present in a bioplastic?

Bioplastics are sourced from renewable resources, such as cornstarch or sugarcane. Whereas, other plastics are made from petroleum. Some plastics are biodegradable, while others are not. Thus, no universally agreed-upon percentage threshold value marks the minimal biobased carbon content or a value to classify a material as 'bioplastic'.

• The European Bioplastics Association (EBPA) has proposed a definition of bioplastics. This includes a minimum biobased carbon content of 50%. But this is not a universally accepted value.
• The USDA BioPreferred® Program clarifies that bioplastics must be made from at least 70% renewable resources. It also emphasizes that bioplastics must meet certain biodegradability standards.

Thus, it can be said that it is up to the certifying body to consider plastics as bioplastics. So, when choosing, OEMs and part manufacturers should check the label and the authorizing body to select the right grade based on their needs. Ultimately, the decision to consider a product as a bioplastic is up to the individual manufacturer or organization. When choosing a bioplastic product, it is important to check the label. This allows to see the percentage of the product that is biobased and if it is biodegradable.

Factors determining biobased content of a bioplastic

The environmental impact of a bioplastic product depends on several factors that include:

• The source of the raw materials used to make the bioplastic
• The production process used to make the bioplastic
• The final properties of the bioplastic

NOTE - Biobased carbon/mass content of a bioplastic is not always a reliable indicator of its environmental impact. For example, a bioplastic that is made from cornstarch may have a higher biobased carbon content than the one made from petroleum. But, the petroleum-based bioplastic may be more biodegradable.

Which certifications and labels govern biobased plastics?

The plastics industry has accepted the need to develop biobased alternatives to fossil-based plastics to facilitate consumer demands. The material suppliers are including renewable variants in their sustainability plans. This enables to meet the requirements of the Green Deal and Climate Plan by 2030. But amongst the plethora of information available, there have been a few questions:

• How can one identify the certification to have?
• Why there is a need to get your products certified?
• What are the certifications and labels you should be aware of?

Certifications and labels are important indications for the sustainable nature of any product. Standardization aims to strengthen homogeneity by overcoming unclear or inconsistent specifications. This provides an industry standard to prevent false claims. The key standardization bodies are:

• European Committee for Standardization (CEN)
• American Society for Testing and Materials (ASTM)
• International Organization for Standardization (ISO)

CEN — European standards¹

The technical specifications for measuring biobased content are released by the European Committee for Standardization (CEN) Technical Committee:

• CEN/TS 16640 — It determines the biobased carbon content using the radiocarbon method. It is applicable to all biobased products. The CEN 16640 standard expresses the carbon as a percentage of total carbon. The three test methods used for calculation are:
  
  
  • Method A: Liquid scintillation-counter method (LSC) (normative)
  • Method B: Beta-ionization (BI) (informative)
  • Method C: Accelerator mass spectrometry (AMS) (normative). The bio-based carbon content is expressed as a fraction of the sample mass or as a fraction of the total carbon content. This calculation method applies to any product containing carbon, including bio-composites.


• CEN/TS 16137 and CEN/TS 16295 — They measure the biobased carbon content of plastics. These methods are based on radiocarbon analysis. They are only applicable to polymers.


• EN 16785–1 — Biobased products – Biobased content – Part 1: It determines the biobased content. This method uses radiocarbon and elemental analysis.

ASTM D6866²

It determines the biobased content of solid, liquid, and gaseous samples. It is the most widely used test method to assess the percentage of modern carbon (pMC) vs the fossil carbon content. It uses radiocarbon (C14) content detection techniques. The ASTM D6866 standard expresses carbon as a percentage of total organic carbon. This standard utilizes two methods to quantify the biobased content of a given product:

• Accelerator Mass Spectrometry (AMS) along with Isotope Ratio Mass Spectrometry (IRMS) or
• Liquid Scintillation Counters (LSC) using sample carbon that has been converted to benzene

USDA BioPreferred® program³

This certification program determines product and package biobased content for worldwide participants. It is a voluntary program. It uses a process that requires independent laboratory testing according to ASTM D6866. Explore all USDA BioPreferred®-certified products offered by top suppliers.

ISO 16620⁴

It includes C14 analysis. It expresses biobased carbon content as a fraction of sample mass, total carbon content, or total organic carbon content. The published standards are:

• ISO 16620-1:2015 Plastics: General principles
• ISO 16620-2:2019 Plastics: Determination of biobased carbon content
• ISO 16620-3:2015 Plastics: Determination of biobased synthetic polymer content
• ISO 16620-4:2016 Plastics: Determination of biobased mass content
• ISO 16620-5:2017 Plastics: Declaration of biobased carbon content, biobased synthetic polymer content, and biobased mass content

Advantages of certifications and labels

In the polymer industry, the certifications and labels are widely used as a fast and reliable protocol. They assess the biobased content at different stages of the industrial process, such as:

• the control of the raw materials
• the optimization of the synthesis process
• the certification of ready-to-market products, as well as
• the control of the bio-content in products already on the market

What are the biobased content values for several plastics?

Click to find the polymer you are looking for:
A-C     |      PA-PL     |      PS-X

Polymer Name	Min Value (%)	Max Value (%)
Bio Polyether Block Amide, PEBA (28-32%renewable carbon)	28.0	32.0
Bio PEBA(44-48% renewable carbon)	44.0	48.0
Bio PEBA(62-66% renewable carbon)	62.0	66.0
Bio PEBA(77-81% renewable carbon)	77.0	81.0
Bio PEBA(87-91% renewable carbon)	87.0	91.0
Bio PEBA(93-97% renewable carbon)	93.0	97.0
CA - Cellulose Acetate	100.0	100.0
CAB - Cellulose Acetate Butyrate	100.0	100.0
CP - Cellulose Propionate	100.0	100.0
PA 11 - (Polyamide 11) 30% Glass fiber reinforced	100.0	100.0
PA 11, Conductive	100.0	100.0
PA 11, Flexible	100.0	100.0
PA 11, Rigid	100.0	100.0
PCL - Polycaprolactone	0.0	0.0
PE/TPS Blend - Polyethylene/Thermoplastic Starch	0.00	39.0
PGA - Polyglycolides	100.0	100.0
PHB - Polyhydroxybutyrate	100.0	100.0
Poly(hydroxybutyrate - co- valerate) PHB-V(5% valerate)	100.0	100.0
PLA - Polylactide, Fiber Melt Spinning	100.0	100.0
PLA, Heat Seal Layer	100.0	100.0
PLA, High Heat Films	100.0	100.0
PLA, injection molding	100.0	100.0
PLA, Spunbond	100.0	100.0
PLA, Stretch blow molded bottles	100.0	100.0
TPS/PE BLend - Thermoplastic Starch/ Polyethylene Blend (30 micron films tested)	40.0	59.0
TPS, Injection General Purpose	100.0	100.0
TPS, Water Resistant	100.0	100.0

References

1. https://www.cencenelec.eu/
2. https://www.astm.org/
3. https://www.biopreferred.gov/BioPreferred/
4. https://www.iso.org/iso-name-and-logo.html