pps proceeding - Abstract Preview
pps proceeding
Symposium: S06 - Polymer Nanocomposites
Oral Presentation
 
 

Agricultural Water Reservoir as Delivery Matrix: Preparation of Pesticide and Nutrient Loaded Halloysite Nanotubes and Their Impregnation in Superabsorbent Polymers

Rodop Ogeday (1)*, Menceloğlu Yeşim (1), Seven Merve Senem (1)

(1) Sabanci University - Istanbul - Turkey

Agriculture uses 70% of freshwater, globally. Superabsorbent polymers (SAP), through absorbing and releasing large amounts of water over extended time periods near the root area, can decrease agricultural irrigation demand and prevent yield losses. Pesticides and fertilizers are used excessively to increase crop production; however, their overuse degrades soil fertility and pollutes the environment. By integrating the sustained release of pesticides and fertilizers in SAP, it is possible to achieve tremendous water savings, offer crop protection with fewer chemicals, supply necessary nutrients, and alleviate water and soil pollution due to pesticide and nutrient contamination, at the same time. Halloysite nanotubes (HNTs) are highly abundant, natural, hollow aluminosilicate materials, which have mainly hydroxyl groups at their surface, and these properties render them suitable to be used as carriers for loading and sustained release of various active agents – pesticides, nutrients, enzymes, and others. In this study, the vacuum suction method was used to load pesticides on HNTs. This way, active molecules can be adsorbed on both the outer surface and inner lumen. Desorption and hence release from outer surface is rapid, whereas from inner lumen is slower. To load micronutrients, HNTs were complexed with PEG chains. Firstly, HNT surface was modified with organosilane coupling agent 3-(Triethoxysilyl)propyl isocyanate (IPTS), to obtain interfacial media between HNT surface and guest molecules to be attached. Then, the resultant product was chemically coupled with PEG chains. Finally, obtained HNT complexes were mixed with micronutrient solutions for 12 hours to achieve loading. A novel SAP nanocomposite was synthesized by free radical polymerization of acrylic acid, acrylamide, and 2-Acrylamido-2-methylpropane sulfonic acid. Active agent-loaded halloysite nanotubes were added to the polymerization reaction, in which water was the solvent. Obtained SAP nanocomposites exhibited approximately 600 g/g swelling in water and released water for more than 20 days. Furthermore, SAP nanocomposites exhibited superior mechanical properties compared to regular SAP.