Synthesis and performance of polyurethane coated urea as slow/controlled release fertilizer

Abstract

Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10–15 μm were formed on urea surface, the urea nitrogen slow-release time can reach 40–50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.

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Correspondence to Limin Wang 王利民 or Jinming Wang.

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Funded by the National Key Technology R&D Program of the 11th Five-Year Period (No.2006BAD10B08)

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Li, Q., Wu, S., Ru, T. et al. Synthesis and performance of polyurethane coated urea as slow/controlled release fertilizer. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 27, 126–129 (2012). https://doi.org/10.1007/s11595-012-0421-7

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Key words

  • polyurethane elastomer
  • coated urea
  • slow / controlled release fertilizer
  • paraffin