Preparation Of CMC Gels And Its Application As Controlled Release Carriers

The application of controlled-releasing agrochemicals is one of important approaches which can decrease the usage amounts of agrochemicals and reduce water and soil pollution. In this research, carboxymethyl cellulose (CMC) gels were used as controlled delivery matrices. The preparation of CMC gels and its composites with bentonites were investigated and their properties of delivering and releasing agrochemicals were discussed. The research objective is to provide technical support for the preparation of novel agrochemicals.The gels of carboxymethyl cellulose and its composites with bentonites were prepared, and their potential applications as carriers for agrochemicals were investigated. The gels had good performance on controlling the release of potassium nitrate and herbicide acetochlor.The preparation of CMC gels was mainly influenced by factors like concentration of crosslinking agents and crosslinking time. The release experiments in water indicated that, the longer the crosslinking time for gel carriers, the slower the active agents released. The drying process could prolong the t₅₀ value, the time taken for 50% of acetochlor to be released, by more than 10 times.Bentonite and its modified products could provide good adsorption to herbicide, and were added into CMC gels to prepare composite gels, which could further slow the release of acetochlor. The higher the sorption capacity of bentonites, the stronger the capacity of gels on controlling the herbicide release. The composite gels from bentonite pillared by aluminum hydroxide provided the longest t₅₀ value of 667.8 h.The status of water in gels was analyzed with differential scanning calorimeter, and the bonding action of acetochlor to carriers was investigated with infrared spectrum. The release of acetochlor from gels was mainly controlled by Fickian diffusion according to the model analysis.