TDPA™ is added at low concentration to conventional plastics, without any specialised manufacturing equipment or processing, rendering it oxo-biodegradable at the end of its useful life. During its lifespan, TDPA™ plastics retain the physical and mechanical properties of the original plastics, and are compatible with standard recycling streams. TDPA™ oxo-biodegradation is a two-phase process:
1. Oxidative Degradation
The first phase is oxidative degradation, where TDPA™ acts as a catalyst causing polymer chain scission, resulting in long plastic polymer chains breaking down into progressively shorter chains. This process is further accelerated by heat, UV light and mechanical stress. Eventually, they become small oligomer molecules that are inherently biodegradable in the environment, and are readily consumed by micro-organisms. TDPA™ oxo-biodegradable plastics are designed to degrade between 12 to 36 months, depending on the specific product applications and the environment.
The second phase is biodegradation, which occurs concurrently with oxidative degradation. During biodegradation, the short chains (oligomers) are consumed by micro-organisms, such as bacteria and fungi, and converted into carbon dioxide, water and biomass. Thus, TDPA™ plastics leave no trace of microplastics or other harmful residues upon completion of biodegradation. The rate of biodegradation depends on the disposal environment; for example, independent testing of polyethylene with TDPA™ achieved 60% biodegradation in soil in less than 2 years (Chiellini et al., 2003).