Disintegration and Biodegradability

Disintegration and biodegradability testing

As consumers start looking more into the environmental footprint of the products they use, there is an increasing tendency of products being marketed as ‘biodegradable’, ‘compostable’, ‘degradable’ or ‘recyclable’ in the market.

However, before making such marketing claims over these terms, it is crucial to understand what it means by them.

Biodegradable, in general terms, refers to the decomposition and break down of materials in a natural environment with microorganisms, fungi, or bacteria.

To validate such claims, brands, retailers and suppliers should look into the end of life (EOL) of a product when selecting materials for use. They can leverage the expertise of our network of companies in terms of EOL terminology as well as capability in disintegration testing and biodegradability testing.

Disintegration Testing

ISO 20200

Designed specifically for plastic materials, this test method enables the determination of the degree of disintegration under simulated aerobic composting conditions to be evaluated, via sieving and change in mass techniques. Thereby providing an indication of the likelihood of a plastic to disintegrate when placed in a compost environment. Dependent on the degree of disintegration observed at key stages, this test can take 3 - 6 months to complete.

ISO 20200 Modified

Traditionally this method is used to evaluate the disintegration of plastics. However, other industries, including the leather industry, can use the modified method by substituting the plastic test substrate with a leather or textile. This method measures disintegration of the test substrate in a test that can take 3 - 6 months, depending on the disintegration results. In addition, compost nutrient and toxicology testing can be performed on completion of the ISO 20200 testing, as an additional service, if required.

ISO 20200 Supplementary Testing

To support the percentage disintegration results collected in ISO 20200 and ISO 20200 modified analysis, additional compost nutrient and toxicology testing can be performed on completion of the ISO 20200 testing, as an optional extra:

EcoTox Testing
An important consideration when evaluating EOL is the toxicity of breakdown products, which may enter the environment. The EcoTox (in accordance to the Eurofins TerrAttesT^®), is used to evaluate the end compost of ISO 20200 analysis measuring 200+ components quantitatively including (but not limited to): Metals, Volatile Organics, Phenols, Chlorinated Hydrocarbons, Petroleum Hydrocarbons, Nitrogen and other pesticides etc.
Plant Response Testing and Weed Tests
To evaluate the impact of degraded or undegraded materials when placed in compost/soil, plant response testing can be a useful indicator. Taking ground up substrates and incorporating them into soil growth media at known concentrations, official cultivars of crop or non-crop plants are then planted in these soils to check weed propagules or bio-enrichment or bio-suppression by the material constituents. Methods available include: WRAP 3.0, OECD 301 and ASTM E1963.

Other disintegration tests that can be applied to the plastics and packaging materials include:

DIN EN 13432 Requirements for packaging recoverable through composting and biodegradation
ISO 16929 Plastics — Determination of the degree of disintegration of plastic materials under defined composting conditions in a pilot-scale test
GB/T 19811 Determination of The Degree of Disintegration of Plastic Materials Under Defined Composting Conditions in a Pilot-Scale Test

Biodegradability Testing

ISO 20136

The ISO 20136 method is a leather-specific method, to determine degradability by microorganisms. In this technique, leather grindings are exposed to an inoculum in an aqueous medium and the rate of aerobic biodegradation of hides and skins (tanned or not tanned), through CO₂ production (via collagen degradation) is determined.

Other biodegradability tests on plastics and packaging items used for apparel, leathergoods or footwear goods include:

BS EN 13432 Packaging. Requirements for packaging recoverable through composting and biodegradation.
ISO 14855-1 Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions — Method by analysis of evolved carbon dioxide — Part 1: General method
ASTM D5338 Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures
GB/T 19277-2003 Determination of The Ultimate Aerobic Biodegradability and Disintegration of Plastic Materials Under Controlled Composting Conditions--Method by Analysis of Evolved Carbon Dioxide
BS EN 13432:2000 Packing requirement for packing recoverable through composting and biodegradation
ASTM D6400 Specification for labelling of plastic designed to be aerobically composted in municipal or industrial facilities
DB/T 505-2020 General requirement for biodegradable plastic shopping bags
GB/T 28018-2011 biodegradable plastic refuse sack