Supramolecular Design Strategy of a Water-Soluble Diphenylguanidine-Cyclodextrin Polymer Inclusion Complex.

Diphenylguanidine (DPG) is a widely used secondary accelerator for the vulcanization of natural rubber (NR) latex. However, its low water solubility and high toxicity limit its use in high-end NR products. In this study, a water-soluble inclusion complex of DPG and a β -cyclodextrin polymer ( β -CDP), termed DPG- β -CDP, was prepared through supramolecular interactions and characterized using Fourier-transform infrared spectroscopy, 1 H NMR, scanning electron microscopy, and UV-vis spectroscopy techniques. In comparison with that of DPG, the water solubility of DPG- β -CDP was greatly enhanced because of the water-soluble host molecule. The molar ratio of DPG to the CD unit in β -CDP was determined to be 1:1. At 25 °C, the binding constant of DPG- β -CDP was found to be 9.2 × 10 5 L/mol by UV-vis spectroscopy. The proposed method for forming inclusion complexes with high potential for use as water-soluble vulcanization accelerators is promising.