Poly(vinyl alcohol)/Premna Oblongifolia Merr. Extract/Glutaraldehyde/Carbon Nanotube (VOGC)-Based Composite Hydrogel:...

A hydrogel based on poly(vinyl alcohol) (V), Premna Oblongifolia Merr. extract (O), glutaraldehyde (G), and carbon nanotubes (C) has been synthesized in search of candidates to develop controlled-release fertilizers (CRF). Referring to previous studies, O and C can be considered as two materials that have potential as modifiers in synthesizing CRF. This work is comprised of hydrogel synthesis, their characterisation, including measuring swelling ratio (SR) and water retention (WR) of VOG_m , VOG_e , VOG_m C₃ , VOG_m C₅ , VOG_m C₇ , VOG_m C₇ -KCl, and release behaviour of KCl from VOG_m C₇ -KCl. We found that C interacts physically with VOG, increased the surface roughness of VOG_m , and reduced the VOG_m crystallite size. The addition of KCl into VOG_m C₇ reduced the pore size and increased the structural density of VOG_m C₇ . The thickness and the C content of VOG affected its SR and WR. The addition of KCl into VOG_m C₇ reduced its SR, but did not significantly affect its WR.