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HPMC layered tablets modified with chitosan and xanthan as matrices for controlled‐release fertilizers
Author(s) -
Melaj Mariana A.,
Daraio Marta E.
Publication year - 2014
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.40839
Subject(s) - swelling , chitosan , fertilizer , materials science , fick's laws of diffusion , diffusion , polymer , chemical engineering , xanthan gum , controlled release , chemistry , composite material , nanotechnology , thermodynamics , organic chemistry , physics , rheology , engineering
Polymeric matrices based on hydroxypropyl methylcellulose (HPMC) with xanthan (X) or chitosan (Q) and using KNO 3 as a model fertilizer were prepared as three‐layered tablets and assayed as controlled release fertilizers (CRFs). The dynamic swelling behavior was analyzed in order to interpret the water uptake mechanism, which in general proved to be non‐Fickian. The presence of HPMC allows a substantially constant rate of fertilizer release. The release mechanism of KNO 3 was analyzed and can be described as non‐Fickian diffusion, with release exponents ranging from 0.85 to 1.01, suggesting polymer relaxation as the major process controlling fertilizer release. Durability in soil indicates the blend Q‐HPMC as the more long‐lasting matrix of those tested, remaining at least 34 weeks. Both blends improve HPMC properties for agronomical applications, with X‐HPMC increasing the swelling rate and Q‐HPMC extending the permanence in the soil. Therefore, layered X‐HPMC and Q‐HPMC matrices can be proposed as suitable materials for the development of CRFs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40839.