Oxo-biodegradation of HD Polyethylene by the use of ReverteTM
ASTM D6954-04 Standard Guide for Exposing and Testing Plastics that Degrade in the Environment Standard Guide for Exposing and Testing Plastics that Degrade in the Environment by a Combination of Oxidation and Biodegradation comprises three Tiers of testing; oxidation, biodegradation and ecotoxicity. HDPE containing ReverteTM oxo-biodegradable additive has been tested through these three tiers, cascading the starting material consecutively through the test program. The results of this test program are presented below;
Tier1: The determination of molecular weight (MW) of HDPE containing ReverteTM exposed to a combination of UV and elevated temperature demonstrates that ReverteTM for High Density Polyethylene significantly accelerates the rate of oxidation.. The ASTM D6954 MW requirement of <5000 has been achieved as reported in Smithers RAPRA report 52286. This oxidation of the PE molecular structure causes mechanical degradation and consequent fragmentation of the material into smaller and smaller pieces and ultimately into powder.
Tier 2: The degree of biodegradation is determined using the oxidised material compliant with Tier 1. The oxidised HDPE material, above, has been shown to mineralise under aerobic conditions when tested to ASTM D5338-98 Standard Test Method for Determining Aerobic Biodegradation of Plastics Materials Under Controlled Composting Conditions, meeting the requirements of ASTM D6954-04, of >60% conversion of available organic carbon to carbon dioxide, in 10 weeks as per report 795-11028-1 by Biosystems Atlanta, Georgia, and certified below.
Tier 3: The residue from the above ASTM D6954-04 Tier 2 biodegradation testing was tested for eco-toxicity with regards to the Tier 3 requirements of ASTM D6954-04. The materials were tested to, and shown to be in compliance with the requirements of OECD Guidelines for the Testing of Chemicals; TG 207 Earthworm Acute Toxicity Tests and TG 208 Toxicity to Terrestrial Plants as per report 795-11046-1-T3 by Biosystems Atlanta, Georgia, and certified below.