Characterization of recycled plastics and textiles

In a circular economy, materials from products at the end of their lifecycle should be recovered through dismantling and recycling. Re-injecting these materials into the beginning of the product lifecycle reduces environmental impact and costs of production.

It is however necessary to assess the exact chemical composition of the recyclates, i.e. their chemical safety for consumers and the environment.

Therefore, Centexbel has installed two new lab devices facilitating the characterization of recyclates and to assess the recyclability of materials.

Grinding and homogenizing recyclates

SPEX Cryomill 6875D is a high-throughput, dual chamber, cryogenic grinder with automatic fluid nitrogen feed. The samples are chilled in liquid nitrogen and then pulverized with a magnetically driven rapidly moving impactor. In contrast to the majority of cryogen grinding techniques, there is no contact between the fluid nitrogen and the sample material.

The Cryomill set up at Centexbel is equipped with accessories to grind samples in the 0.1-gram to 100-gram range. The aparatus also allows to homogenize the materials, which is especially interesting to characterize recyclates, and to “dilute” materials containing functional additives by adding virgin materials.

Dynamic Headspace GCMS: Assessing the presence of VOC/SVOC

This finely ground material can then be further analyzed in the newly installed Gerstel dynamic headspace GCMS, on the presence of VOC and SVOC in textiles and plastics (e.g. REACH compliancy) in a fully robotized manner. By grinding the compact plastics, the diffusion factor is no longer hampering the analysis and allows us to reach results much faster and to gain information about heavier and/or more polar substances.

The apparatus has been equipped with a large volume Dynamic HeadSpace (DHS) sampler in view of analyzing recyclates which allows us to go beyond the normal sample dimension of 20 mg (which is irrelevant for recyclates) to 10 g.