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Study On The Surface Activity And Mechanism Of Nano-Calcium Carbonate

Posted on:2008-03-18Degree:MasterType:Thesis
Country:ChinaCandidate:J J ShuFull Text:PDF
GTID:2121360218457818Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
Nano-CaCO3 is an inorganic powder material,it's surface is near water and distant oil,and it can't take place chemical contact with macromolecule organic matter,and it has not strengthening capability. In the meantime,Nano-CaCO3 has huge specific surface area,and very big specific surface energy,and easily take place to combine and reunite among powders in it's making and rear-disposal courses,and it can form second particulates,and it's particle diameter will grow up,it will lose all ability of nanophase materials in the course of application. The key which answers the two questions lies in changing character on it's surface,and reduce surface energy, and raise it's near oil character,and develop it's dispersity and dispering stability in base material,and raise it's compatibility with macromolecule organic matter,and make it become an function filling and capability raising agent from amount raising agent.The main gap of the quality of nano-CaCO3 between our country and developed country are denoted by poor conformanability and dispersion of crystals, low surface activity technology.This is due to the beginning of surface activity technique on nano-CaCO3 in our country was very late, the surface activity technique is not mature, in especial, the surface active mechanism still is not very clear, this is an important bottle-neck of restricting development of the surface activity technique and also is the research direction in the article. First, a lot of experiments about changing character on CaCO3 surface has been rearsched,example,fatty acid (salt),pentaerythritol,rosin ester,cocoanut oil,rosin, pentaerythritol + rosin ester,glycerine + rosin ester ,cocoanut oil + oleic acid,titanate + fatty acid (salt),cocoanut oil + fatty acid (salt), and so on surface active agents. Among these surface active agents, cocoanut oil + oleic acid,and titanate+ fatty acid (salt),and cocoanut oil + fatty acid (salt) are the best.Second, the theoretical principle of changing character on it's surface structure has been introduced, the structure model of CaCO3 molecule has been founded,and the structure characteristics of CaCO3 particulate have been cleared about,namely CO32- is bigger than Ca2+ in the CaCO3 molecule,and CO32- will bring steric-effect. Overwhelming majority surface area of CaCO3 particulate will be occupied by CO32- which bears negative charges,So CaCO3 particulate can absorb in calcium ion (Ca2+). This estabilishes the base for founding the structure model of activity CaCO3 ,and studying surface activity mechanism.Finally, surface active mechanism of nano-CaCO3 has been studied, example for fatty acid (salt),phosphate ester,titanate,aluminate and so on four kinds surface active agents are illustrated. Meantime, the structure model of carbonate calcium molecule has been founded. The long term potential of CaCO3 industry has been overlooked, the CaCO3 industry still is the rising sun industry.
Keywords/Search Tags:nano-CaCO3, structure model, surface activity mechanism
PDF Full Text Request
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