Investigating the Impact of Seasonal Input Stream Fluctuations on Post-Consumer High-Density Polyethylene Composition...

Area of Science:

• Materials Science
• Polymer Recycling
• Sustainable Waste Management

Background:

• Plastic recycling into post-consumer recycled (PCR) materials is vital for sustainable waste management.
• Processing PCR materials is challenging due to seasonal variations in waste streams and material composition.

Purpose of the Study:

• To analyze the impact of batch-to-batch fluctuations on the processing stability and product properties of high-density polyethylene (HDPE) PCR.
• To investigate how variations in batch composition affect processing parameters, mechanical properties, and product quality.

Main Methods:

• Analysis of six consecutive HDPE PCR batches for composition, contaminations, and rheological characteristics.
• Utilized ashing, differential scanning calorimetry, high-temperature gel permeation chromatography, and capillary rheometry.
• Processed materials via blown- and cast-film extrusion and injection molding.

Main Results:

• Batch composition variations strongly correlate with changes in processing data (injection pressure, torque).
• Fluctuations in thermal properties (crystallization enthalpy), molecular weight, polypropylene (PP) content, and viscosity impact mechanical properties (tensile strength, E-modulus, impact strength).
• Processing variations lead to changes in product quality, including gel formation, dimensions, and weight.

Conclusions:

• Batch-to-batch variations in HDPE PCR significantly affect processing stability and product properties.
• Understanding and managing these variations is crucial for consistent and reliable production of recycled plastics.
• Material characterization and process control are key to overcoming challenges in PCR utilization.