ASTM D6691：海洋环境中塑料材料的有氧生物降解

What is the ASTM D 6691?

The ASTM D6691:2017 is a test method carried out under controlled laboratory conditions. It aims to characterise polymer materials that have the potential to be biodegradable in a marine environment. Determining the biodegradability of a polymer is paramount for the evaluation of the ecological behaviour of materials. Biodegradability is a key parameter, as it ensures the degradable substance will not cause long-term risk in the environment.

We currently live in a world where plastic waste is a problem, particularly with ships at sea. As plastics are becoming more prevalent on ships, their end-of-life disposal must be considered, as the chances of plastics being disposed of at sea will always exist. Therefore, we must consider the biodegradation mechanisms within a marine environment.
The ASTM D6691:2017 standard applies to any polymer material containing a minimum of 20% carbon content that is not inhibitory to the microorganisms already present in the marine environment.

如何在海洋环境中测试塑料的生物降解性？

A test sample will be assessed for the characterisation of carbon content and molecular weight before testing. Firstly, it is crucial to prepare the marine environment for the test by ensuring that it has the correct microorganisms present. Secondly, the polymer sample will be submerged in the inoculum (marine solution) in a Biochemical Oxygen Demand (BOD) system.

BOD系统包括测试瓶和二氧化碳传感器，共同创建了一个封闭的系统。海洋溶液中的微生物将慢慢消耗聚合物样品并同时发展二氧化碳。结果，它会在BOD系统中产生压降。BOD的测量原理是检测到这种压力下降。BOD传感器将显示Mg/L O2的BOD值。

According to the ASTM D6691, the biodegradability of the sample material is determined by the released CO2 (biogas) measured through the use of arespirometer. The biogas is the conversion of our polymer to CO2, as noted in the percentage of conversion. The measured biogas produced is used to determine biodegradability, by comparison to a known reference.

典型的呼吸仪类型系统可以在10-90天之间运行。然而，如果样品极具生物降解，则可以在累积的二氧化碳生产高原时终止实验。同时，如果在特定时间表中未发生生物降解，则可以扩展实验。

impact solutionsare set up to carry a series ofBiodegradability提供完整材料分析服务的测试：基于BS EN 13432方向的化学，环境，元素，以及我们可以适应有氧和厌氧的所有类型的实验室尺度生物降解性测试。