Researchers at the University of Waterloo announced on November 5 a plant-based coating for paper cups that could remove petroleum-based plastic from the hot-drink cup entirely. The coating is cellulose acetate reinforced with cellulose nanocrystals — both plant-derived — and the work was published in ACS Sustainable Chemistry & Engineering (Ganguly et al., 2026).
The problem it targets is familiar. Most disposable paper cups rely on a thin polyethylene lining to hold hot liquid. That lining is difficult to separate from the paper, which complicates recycling, and it can flake under heat and abrasion. In Waterloo's tests, the new coating remained largely intact after prolonged exposure to boiling water, food oil, and solvents, while conventional plastic liners flaked. Because coating and cup are both cellulose-based, the material has the potential to simplify paper recycling by reducing the need to strip a plastic liner from the paper.
It is still early-stage work. The coating has been demonstrated on lab-coated paper samples; it has not yet been tested on a factory line, and no cost per cup has been reported. The microplastics benefit is also a potential rather than a measured result — the study reports surface and abrasion behaviour, not particle counts in a drink. And this is a recycling story, not a composting one: the university has not claimed industrial-composting certification for the coating.
For Greenstar, the development is worth watching because it shows the industry pursuing more than one end-of-life route for the same product. Our PLA-lined hot-drink cups are designed for industrial composting, certified to ASTM D6400 and EN 13432. Waterloo's coating points toward a recyclable cup instead. Both aim at the same goal — a cup without conventional plastic — and buyers should ask which end-of-life route a product is actually designed and certified for.
Disclaimer: Product descriptions, specifications, and certification references in this article are provided for general information. Compostability claims (including ASTM D6400, EN 13432, and GB/T 19277) refer to industrial composting conditions; commercial composting facilities may not be available in all communities. Certifications apply only to the specific products listed in the relevant certificates. For current certification documentation, contact Greenstar@greenstarmaterial.com.