(217d) Use of Surfactants to Deink Plastics

If used polymer items are sorted into single component streams, one of the most, if not the most significant factor that reduces the quality of the product is the inclusion of non-polymeric materials into the recycled materials. One common non-polymeric materials, especially on flexible film used in film packaging, is ink. I will present our efforts on using surfactants to deink both flexible and rigid polyethylene-based materials. Our work has shown that high pH and cationic surfactants are most effective for deinking as measured by colorimetric measurements. The proposed mechanism involves both solubilization of the likely negatively charged polymer binder as well as wetting of the negatively charged particles. Other types of surfactant are effective at deinking as well. The tensile strength and elongation at break after deinking are significantly better than the material recycled without deinking, but still are slightly lower than the un-inked material. Finally, I will discuss parallels and differences of deinking with respect to washing of clothes as well as how surfactants would be effective in removing food, oil and grease.