Studies On The Water Super Absorbing And Retaining Material Of Surface Modified Vermiculite

Super absorbents(SAP) can absorb a large amount of water compared with general water absorbing materials in which the absorbed water is hardly removable even under some pressure .It is a new-style developed functional macromolecule material in recent 30years,and it is widely used in agriculture, horticultural applications, sanitation, architecture and so on. The more important role is played in lots of fields recently and a huge market potential is forecasted. However, traditional SAP can't be used in the large scale because of its expensive production cost, weak salt-resisting and water-holding capacity.The study is regard to the current situation in the north of China even in the northwest such as little rainfall, low soil organic content and poor water holding capacity. To reduce the production cost and simplify the production technology, the research adopts the expanded vermiculite as the main raw material and we modify its surface to get the super absorbent of surface modified vermiculite. The experiment shows that it is easy to control with simple process and short cycle.The influences of the sort of surfactants and their content on the super absorbent of surface modified vermiculite were studied .It shows that the absorption was determined as the content of sodium dodecyl benzene sulfonate (SDBS), methylcellulose (MC) and sodium hexametaphosphtte, and polyethyleneglycol (PEG) influences the material's water holding capacity. And the results also show that SDBS of 15wt%, MC of 10wt%, sodium hexametaphosphtte of 60wt% and PEG: H2O of 1:4 are the optimal conditions.The analysis of XRD, IR and Laser Particle Size shows that MC is well absorbed on the surface of expanded vermiculite, but the absorption amount of SDBS, sodium hexametaphosphtte in the individual way is not very good .With the accession of PEG, their absorption amount is increased and the water holding capacity of the production is also enhanced.With water absorption theories of traditional super absorbent, the water-absorbing mechanics of the super absorbent of surface modified vermiculite was preliminarily researched. We found that in the process of the modification of expanded vermiculite, surfactants'hydrophobic groups are absorbed on the surface of the vermiculite with the effects of their electrostatic repulsion and steric hindrance; the hydrophilic groups are on the outside. Because of this, the super absorbent of surface modified vermiculite has the capacity of water holding.