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Multilayer‐coated NPK compound fertilizer hydrogel with controlled nutrient release and water absorbency
Author(s) -
Noppakundilograt Supaporn,
Pheatcharat Natthaya,
Kiatkamjornwong Suda
Publication year - 2015
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.41249
Subject(s) - fertilizer , ammonium persulfate , glutaraldehyde , acrylic acid , materials science , nuclear chemistry , monomer , polymer chemistry , polymerization , chemistry , self healing hydrogels , polymer , composite material , organic chemistry
A novel trilayered controlled‐release nitrogen, phosphorous, and potassium (NPK) fertilizer hydrogel was prepared by dipping the NPK fertilizer granules sequentially in 7% w v − 1 poly(vinyl alcohol) (PVA) and 2% w v −1 chitosan (CS) solutions and then cross‐linking the CS layer ( cross ‐CS) via glutaraldehyde vapor deposition. Different NPK fertilizer hydrogels were then synthesized by inverse suspension polymerization of the dried PVA/ cross ‐CS bilayer‐coated fertilizer granules in various molar ratios of acrylamide (AM) and acrylic acid (AA) monomers, and polymerization with varying molar ratios of ammonium persulfate, N,N,N′,N′ ‐tetramethylethylenediamine and N,N′ ‐methylenebisacrylamide ( N ‐MBA). The water dissolution time of the obtained PVA/ cross ‐CS/poly (AA‐ co ‐AM) trilayer‐coated NPK fertilizer hydrogel granules was prolonged, while the water absorbency increased with increasing AA contents, and decreased with increasing N ‐MBA contents in the outer poly(AA‐ co ‐AM) coating. The optimal trilayer‐coated NPK fertilizer hydrogel obtained released 84 ± 18, 63 ± 12, and 36 ± 15% of the N, P, and K nutrients, respectively, after a 30‐day immersion in water. The release phenomena of the N, P, and K nutrients of the fertilizer hydrogel obeyed both the Korsmeyer‐Peppas and Ritger‐Peppas models with a pseudo‐Fickian diffusion mechanism. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41249.