Synthesis and characterization of bio-based PA/EP interpenetrating network polymer as coating material for controlled release fertilizers

A novel controlled release fertilizer was developed using interpenetrating polymer network (IPN) as the coating material. The IPN was successfully sprayed on the surface of the urea particles to form IPN-coated fertilizers (IPNCU) for controlled nitrogen release. The IPN was synthesized by bio-based polyamide (PA) from d -glucaric acid and epoxy (EP) through network interpenetrating. The chemical structure and microscopic morphology characteristics of IPN were examined by Fourier transform infrared spectroscopy, 1 H-nuclear magnetic resonance, and scanning electron microscopy. The property of IPN with the different PA/EP mass ratios were investigated and compared with that of EP-coated fertilizers (EPCU). The nutrient release behaviors of IPNCU in water and soil were detected. The results showed that the IPNCU with 5% PA content increased the nitrogen release longevity by 41 days, raised the water contact angle of surface by 23.9°, and then significantly slowed the nitrogen release rate of the IPNCU. The nutrient release mechanism of IPNCU was discussed in detail. This work indicated that the environment-friendly IPN with superior controlled release properties could be especially useful in horticultural and agricultural applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46052.