Limited utilization options for secondary plastics may restrict their circularity

Area of Science:

• Environmental Science
• Materials Science
• Industrial Ecology

Background:

• Plastic recycling offers environmental benefits by reducing waste and conserving primary resources.
• Current research often overlooks the downstream utilization of recycled plastics in manufacturing.
• Effective plastic waste management necessitates understanding the integration of secondary materials into product lifecycles.

Purpose of the Study:

• To assess the potential for substituting primary plastics with secondary materials in product manufacturing.
• To analyze the impact of increased collection rates on secondary material availability and utilization.
• To identify the limitations of secondary material uptake in achieving higher recycling rates.

Main Methods:

• A material flow analysis was conducted for 11 plastic types across 54 product subsegments in Switzerland (2017 data).
• A prospective scenario for 2025 modeled an 80% collection rate for 2017 plastic fractions.
• Linear optimization allocated secondary material flows to suitable product subsegments under varying applicability scenarios.

Main Results:

• Secondary plastics can substitute 21% to 100% of primary materials, meeting 11% to 17% of total material demand.
• Overall recycling rates could reach 23%, but the true recycling rate, considering only utilized secondary materials, is lower (17% in a moderate scenario).
• Secondary material uptake emerged as a critical limiting factor for enhancing future plastic recycling rates.

Conclusions:

• The successful integration of secondary plastics into manufacturing is crucial for advancing recycling systems.
• Recycling rate targets should be informed by realistic assessments of secondary material application potential.
• Further research and policy development are needed to overcome barriers to secondary material utilization in the plastic industry.