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Permeation of urea through various polyurethane membranes
Author(s) -
Watanabe Atsushi,
Takebayashi Yoshihiro,
Ohtsubo Toshiro,
Furukawa Mutsuhisa
Publication year - 2009
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.1815
Subject(s) - polyurethane , membrane , permeation , polymer , glass transition , chemical engineering , urea , polymer chemistry , materials science , synthetic membrane , chemistry , chromatography , composite material , organic chemistry , biochemistry , engineering
BACKGROUND: Controlled‐release systems using polymer membranes are very important in agriculture for labour‐saving and effective delivery of pesticides and other agents. Polymer‐coated granules are one of the most useful formulations, and a study of the factors for polymer design is necessary to achieve various release patterns. A permeation study using plain membranes was carried out in order to clarify parameters, and the results were compared with the release from polymer‐coated granules. RESULTS: The permeation coefficient of urea through a plain polyurethane membrane decreased significantly as the urethane and alkyl side chain content increased. The glass transition temperature and crosslink density of the polyurethanes hardly influenced its permeability. The release rate from polyurethane‐coated granules was also reduced by alkyl side chains. However, it was faster than that through a plain membrane because of capsule expansion by continuous water penetration and structural changes in the membrane. CONCLUSION: The release rate of urea through a polyurethane plain membrane and from polyurethane‐coated granules can be controlled by changing the chemical properties of the membrane. In addition, physical properties such as the glass transition temperature T g or crosslink density should be considered to assess the release profile from polyurethane‐coated granules. Copyright © 2009 Society of Chemical Industry