Effect of Filler Treatment on the Release Properties of Coating on Urea Granules

ABSTRACT

Polyurethane composite coatings on urea granules were prepared by SBA-15 mesoporous silica (in as-synthesized and calcined forms) as a pseudo-crosslinker without any other chain extenders. The calcination of mesoporous silica leaded to reduction of hydroxyl groups and increase of mesopores. The composite coating containing calcined SBA-15 showed enhanced controlled release properties compared with the other two coatings. At the loading content of 1 wt%, the initial release rate and release duration of urea coated by polyurethane/calcined SBA-15 composite were 0.08% and 83 d, respectively. It is shown that the calcination played an important role in controlling the properties of composite coating.

GRAPHICAL ABSTRACT

KEYWORDS:

• Calcination
• coating
• composite
• controlled release
• urea

Acknowledgments

The authors are grateful for financial support from National Key Research and Development Program of China (2017YFD0200705, 2017YFD0800604) and National Science Foundation of China (31301846, 31301847).

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [2017YFD0200705, 2017YFD0800604]; National Science Foundation of China [31301846, 31301847]