LAUSR

A series of modified bentonite (MBT)/polyurethane (PU) composites were synthesized from MBT, isocyanate, and soybean oil-based polyols by in-situ polymerization to coat urea granules for slowing nitrogen (N) release. Bentonite (BT) was modified by intercalation of polyethylene glycol inside the interlayer space, expanded the BT layer spacing and improved the performance of composites. The MBT and MBT/PU composites were characterized in terms of their structure, thermal stability, mechanical strength, surface wettability, and the urea slow-release performance. With the addition of 5.0 wt% MBT, its tensile strength is 13.53 MPa and breaking elongation is 20.66%, increased by 27.52% and 67.97%, compared with pure PU, respectively. The release duration of the PU-5%-MBT composites coated urea was 74 days. The results indicated that the modified films are suitable for the slow release fertilizers. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers