Development of Fertilizer Coatings from Polyglyoxylate-Polyester Blends Responsive to Root-Driven pH Change

Spencer M. Heuchan, Bo Fan, Jessica J. Kowalski, Elizabeth R. Gillies, Hugh A.L. Henry

Research output: Contribution to journalArticleResearchpeer-review

28 Citations (Scopus)


Many current controlled-release fertilizers (CRFs) are coated with nonbiodegradable polymers that can contribute to microplastic pollution. Here, coatings of self-immolative poly(ethyl glyoxylate) (PEtG) capped with a carbamate and blended with polycaprolactone (PCL) or poly(l-lactic acid) (PLA) were evaluated. They were designed to depolymerize and release fertilizers in the vicinity of plant roots, where the pH is lower than that in the surrounding environment. PEtG/PCL coatings exhibited significant temperature and pH effects, requiring 18 days at pH 5 and 30 °C, compared to 77 days at pH 7 and 22 °C, to reach 15% mass loss. Plant roots were also effective in triggering coating degradation. Spray-coating and melt-coating were explored, with the latter being more effective in providing pellets that retained urea prior to polymer degradation. Finally, PEtG/PCL-coated pellets promoted plant growth to a similar degree or better than currently available CRFs.

Original languageEnglish
Pages (from-to)12720-12729
Number of pages10
JournalJournal of Agricultural and Food Chemistry
Issue number46
Publication statusPublished - 20 Nov 2019
Externally publishedYes


  • biodegradation
  • controlled release fertilizer
  • microplastic
  • pH-responsive
  • poly(ethyl glyoxylate)
  • self-immolative polymer

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