Analyzing Sample Size and Cross-Contamination in Plastic Recycling: A Novel Thermal Analysis Method Coupled with Sampling Theory

A crucial issue in the plastic recycling industry is the loss of quality in recycled materials due to cross-contamination, which leads to excessive material losses. Determining cross-contamination levels in recyclate batches fills a crucial gap in quality control, helping to identify suitable applications and enhance the value of the material stream. A key challenge lies in selecting a sample size that accurately represents the large variability within the tons of batches processed daily. This work presents a data analysis framework to accurately estimate cross-contamination levels in plastic recyclate batches and determine the sample size required to meet industry demands while accounting for both analytical and sampling errors. Additionally, this work introduces MADSCAN, a novel, scale-free thermal analysis technique that allows for the analysis of the sample sizes identified by the framework. Objectives include providing crucial information to industry stakeholders, assisting regulators in establishing quality control processes, and guiding technology providers in advancing measurement techniques for the circular economy, with a focus on meeting sample size and accuracy requirements.