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Issue 04/2017

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  • Bioplastics
  • Biobased
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Basics Biobased carbon

Basics Biobased carbon and mass content Standards and certification Bioplastics are not just one single material but they comprise of a whole family of materials with different properties and for a wide number of applications. According to European Bioplastics, a plastic qualifies as bioplastic if it is either biobased, biodegradable, or features both properties. A plastic material or final product that is biobased is wholly or partly derived from biomass. Today, the renewable biomass used to produce bioplastics mainly stems from agro-based feedstocks, such as corn and sugarcane, or ligno-cellulosic feedstocks. While biobased products can have ecological benefits in comparison to conventional, fossil-based materials, they cannot be identified visually and therefore need to be labelled as biobased. In order to correctly claim and communicate the extent to which a product is biobased, it is necessary to precisely measure the amount of renewable biogenic material contained in it. In the following the most relevant standards for the determination of the biobased content will be introduced as well as the most established certification schemes and labels. Determination of the biobased carbon content Carbon has three naturally occurring isotopes namely 12 C, 13 C, and 14 C, with 12 C being the most abundant. The radioactive 14 C is permanently produced in the upper layers of the atmosphere through nuclear reactions. Down on the earth, plants take up CO 2 from the atmosphere through photosynthesis and thus automatically sequester 14 C and embed it in the biomass. In fossil-based materials, hardly any 14 C can be found due to the radioactive decay of the isotope over tens of thousands of years. These natural processes are behind the so-called radiocarbon method, also known as 14 Cmethod, which is used to determine the biobased carbon content of a plastics material or product. This method is described in various national and international standards. On the European level, EN 16640 was developed by CEN/TC 411 (“Biobased products”) and is supposed to supersede the former CEN/TS 16640. Currently, the technical specification CEN/TS 16137 is also used for certification of the biobased carbon content. The US standard ASTM D6866 also describes the determination of the biobased carbon content based on the radiocarbon method and is used as a basis for biobased content certification in Europe. On the international level, the ISO standard 16620-2 describes the radiocarbon method and is part of a series of standards on the determination of the biobased content. By: Constance Ißbrücker Head of Environmental Affairs European Bioplastics Berlin, Germany Biobased mass content or total biobased content The biobased content of a plastic can not only be measured and communicated by referring to the biobased carbon content, but also by considering other elements frequently present in polymers such as hydrogen (H), nitrogen (N), and oxygen (O). The French Association Chimie du Vègètal (ACDV) originally developed a method for this, combining the radiocarbon method with elemental analysis. However, the principle of different isotopes (as used for carbon with 12 C and 14 C) cannot be used for the other elements H, N, and O. ACDV, and more recently the new standard EN 16785-1, therefore introduced the principle of atom connectivity, which suggests that atoms (such as H, N, and O) covalently bound to a biobased carbon can also be assumed to be biobased. This principle is used as basis for calculating the total biobased content (also referred to as biobased mass content) of a plastic material or product. The amount of biobased carbon is determined through radiocarbon analysis and the carbon atoms are allocated to be of biobased origin or not on the basis of knowledge about the biobased feedstock. The whole composition of the material is furthermore determined by elemental analysis and the other atoms (H, N, and O) bound to the biobased carbon are also considered as renewable. In case they are bound to both a fossil and a biobased carbon, the assignment follows according to feedstock and production background. The calculation of the total biobased bio-based content can then be done as described in EN 16785-1. The approach to determine the biobased mass content in plastic products by radiocarbon and elemental analysis is also described in the international standard ISO16620-4. Part two of the standard - prEN 16785-2 - focuses on a calculation method to determine the total biobased (mass) content of a product. The essence of this method lies in the calculation of material balances of representative product batches in a production unit. The biobased content is calculated on the basis of the quantification of the inputs, the losses, as well as the outputs of materials used in the process (by mass), provided that the total biobased content of each input and loss of material is known and verifiable by analysis. prEN 16785-2 is not published yet, but is expected to be available no later than February 2018. Certification and labels All standards mentioned above describe test methods and do not require a minimum amount or percentage of biobased content. To enable the correct communication of biobased contents through product labelling, these standards have been used to create certification schemes that specify how much biobased (mass or carbon) content must be measured in order to attain the corresponding certificate and product label. In Europe, Vinçotte and DIN Certco offer the most accepted and well-known biobased content labels. DIN Certco certifies the biobased carbon content based on ASTM D6866, CEN/TS 16137 and the ISO 16620 (1-3) 44 bioplastics MAGAZINE [04/17] Vol. 12

Basics Buss Laboratory Kneader MX 30-22 series. All products that have at least an organic content of 20% can be certified with the DIN-Geprüft Biobased label. Depending on the amount of the biobased carbon content, DIN Certco offers three different variations of the label: 20- 50 %, 50-85 %, and >85 %. Vinçotte offers a certification scheme with the name OK biobased. There are two basic requirements to obtain the according labels: (1) the total organic carbon content of the product must be at least 30 %, and (2) the carbon content of a renewable raw material is at least 20 %. The US BioPreferred programme also certifies the content of biobased products in accordance with ASTM D6866. The United States Department of Agriculture (USDA) has identified 97 product categories and determined a required minimum biobased content for each category. All other products must have a biobased content of at least 25 %. The biobased label by the Netherlands Standardisation Institute (NEN) is based on the standard EN 16785-1 and can be used for an independent assessment of claims on the biobased mass content of a product. Other examples of labels based on national initiatives are the Korean Biomaterial Packaging association’s Biobased Label or the BiomassPLA certification from Japan, which are both based on ASTM D6866. It is important to understand that standards and certification of the biobased carbon or mass content of a product cannot be used to make claims about the sustainability of products. For this, separate sustainability certification schemes and labels are available in the market. References: EN 16640 „Biobased products – Determination of the biobased carbon content of products using the radiocarbon method“, 2017 CEN/TS 16137 “Plastics – Determination of biobased carbon content”, 2011 ASTM 6866 “Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis”, 2016 ISO 16620-2 “Plastics – Biobased content – Part 2: determination of biobased carbon content”, 2015 EN 16785-1 „Biobased products – Biobased content – Part 1: Determination of the biobased content using the radiocarbon analysis and elemental analysis“, 2016 ISO 16620-4 “Plastics – Biobased content – Part 4: determination of biobased mass content”, 2016 prEN 16785-2 “Biobased products – Biobased content – Part 2: Determination of the biobased content using the material balance method” J. Sherwood, “Recirculation: A new concept to drive innovation in sustainable product design for biobased products”, Molecules 2017, 22, 48 Open-Bio Project, “Evaluation of applicable techniques for the determination of the biobased content”, 2015 European Bioplastics, Fact Sheet “Bioplastics - Industry Standards and Labels”, 2017 Buss Kneader Technology Leading Compounding Technology for heat and shear sensitive plastics For more than 60 years Buss Kneader technology has been the benchmark for continuous preparation of heat and shear sensitive compounds – a respectable track record that predestines this technology for processing biopolymers such as PLA and PHA. > Uniform and controlled shear mixing > Extremely low temperature profile > Precise temperature control > High filler loadings Buss AG Switzerland bioplastics MAGAZINE [04/17] Vol. 12 45

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