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Release Fertilizer Coating Materials Through Sexual Control Study

Posted on:2008-04-07Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2191360215998469Subject:Materials science
Abstract/Summary:PDF Full Text Request
Polystyrene composite membranes used in this study were prepared by sepiolite (80mesh and 325 mesh), molecular sieve (100 mesh), wood powder (100 mesh and 300mesh), respectively. Permeation performances of the five pairs of composite membraneswere discussed, permeation rules of different filler composite membranes were compared,and the effect of filler content, membrane thickness and particle size of filler onpermeation performance of composite membranes was studied. The surface morphologyof composite membranes were compared. Cumulative amounts of permeation ofdifferent filler composite membranes were fitted by first-class dynamic equation Nt=N(l-e-kt), Elovich equation qt=a+blnt and paracurve diffusion equation qt=a+bt0.5,permeation mechanism of different filler composite membranes were discussed primarily.The results show that the urea permeation amounts of different composite membranes aremore than that of polystyrene membrane obviously. Cumulative amounts of permeationof composite membranes increase with the increasing of filler content gradually,cumulative amounts of composite membranes decrease with the increasing of membranethickness gradually, the larger the filler particle size, the larger the cumulative amounts ofcomposite membranes when filler content and membrane thickness are fixed. In the fivecomposite membranes, cumulative amount of polystyrene/wood powder (100 mesh)composite membrane is largest, and then is polystyrene/wood powder (300 mesh)composite membrane, polystyrene/sepiolite (80 mesh) composite membrane,polystyrene/molecular sieve (100 mesh) composite membrane and polystyrene/sepiolite(325 mesh) composite membrane. Cumulation urea release behaviors of five compositemembrane can be described by fist-class dynamic equation Nt=N(l-e-kt).
Keywords/Search Tags:Polystyrene, Composite Membranes, Filler, Sepiolite, Molecular Sieve, Wood Powder, Urea Permeation Amounts
PDF Full Text Request
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