Preparation and characterization of hydrogels based on glycidyl methacrylate (GMA)‐grafted NR and modified cassava starch as eco‐friendly materials for sustainable agriculture

Abstract

AbstractEco‐friendly hydrogel was developed using natural rubber latex (NR) and cassava starch (CSt) through grafting modifications to enhance their swelling and water retention by selecting suitable grafting components and improving compatibility. To improve its hydrophilicity and compatibility with CSt, NR was grafted with glycidyl methacrylate (NR‐g‐GMA, NRG). Subsequently, CSt was grafted with acrylic acid (AA) and acrylamide (AM), crosslinked with N,N′‐methylene‐bis‐acrylamide (MBA), and ultimately interpenetrated by NRG to produce CSt‐g‐PAA/NRG and CSt‐g‐PAM/NRG hydrogels, respectively. The obtained hydrogels were characterized by various techniques. Results revealed that CSt‐g‐PAM/NRG exhibited exceptional equilibrium water swelling (Seq) at 2413%, surpassing CSt‐g‐PAA/NRG (416%), and CSt/NR (146%). This was attributed to the synergistic effects of the improved NR polarity and compatibility, the looser structures, the higher rate constant of water swelling (20.06%/s), and the greater compatibility between compositions compared to the CSt‐g‐PAA/NRG system. Therefore, AM was the suitable grafting monomer for the CSt/NRG hydrogel system. Also, the CSt‐g‐PAM/NRG hydrogel exhibited remarkable water retention for up to 30 days with excellent biodegradation (55%) and good biosafety. This study demonstrates a promising strategy for improving swelling capacity (~1600%) and water retention (58%) of biodegradable CSt/NR hydrogels as a low‐cost coating membrane for sustainable agriculture.Highlights Boost of NR hydrophilicity and compatibility via GMA grafting to generate NRG. Fabrication of CSt‐g‐PAA/NRG and CSt‐g‐PAM/NRG hydrogels by semi‐IPN technique. CSt‐g‐PAM/NRG swelling showed a significant improvement over CSt‐g‐PAA/NRG. AM was the suitable grafting monomer for the CSt/NRG hydrogel system. CSt‐g‐PAM/NRG showed good biodegradability and water retention for agriculture.