Composition Of Calcium Carbonate And Titanium Dioxide Particles By Hydrophobic Aggregation And Its Characterization

The mineral/TiO2 composite particles material with non-metal mineral as core material and crystallized TiO2 as coating material has a similar performance with titanium pigment and low cost.As a substitute material of titanium pigment it has been used more and more widely.But the preparation methods have promblems of compelx process,high energy consumption and lacking pertinence in applications at present.So It is very necessary and pressing to research new preparation methods,manufacturing processes and relevant basic questions.On the basis of CaCO3 and TiO2 getting hydrophobicity by modifier the paper using hydrophobic aggregation prepared composite particles which had a feature of CaCO3 coated by TiO2 in aqueous medium.The structure,property and composite mechanism of composite particles were studied.The purpose was establishing a new method of preparation mineral/TiO2 that can simplify processing technology,improve material proporty and application specificity.Using sodium stearate and sodium oleate as modifier the technology of CaCO3 and TiO2 hydrophobic regulation by surface modification was researched.The parameters of CaCO3 and TiO2 hydrophobic regulation were optimized and CaCO3 and TiO2 particles which had a feature of strong induced hydrophobicity were gained.By changing the dosages of modifier the particles surface hydrophobic extent could be regulated.The technology of preparation CaCO3/TiO2 composite particles material through CaCO3 and TiO2 hydrophobic aggregation in aqueous medium was researched.The affecting factors of composite process of two kinds particles' hydrophobic extent and combination were investigated and optimized.CaCO3/TiO2 composite particles material had similar performance with titanium pigment and surface hydrophobicity.Therein CaCO3 played a strong pigment synergy.The property of CaCO3/TiO2 composite particles material prepared by hydrophobic aggregation was characterization.The covering power values of compostie products using sodium stearate and sodium oleate regulated particles hydrophobicity were 15.48 g/m2 and 14.93 g/m2 respectively.They reached 89.86%and 93.17%of pure titanium pigment respectively and were much more than the contribution of composite proportion of TiO2(60%).The application effect of CaCO3/TiO2 composite particles material was favorable in paint.The micro appearance and combination ways of CaCO3/TiO2 composite particles material were researched.CaCO3/TiO2 composite particles were composed of CaCO3 surface coating by TiO2.The bond strength between CaCO3 and TiO2 was big and their combination had no existence of chemical actions.The calculated results of van der Waals interaction energies,electrostatic interaction energies and hydrophobic interaction energies between CaCO3 and TiO2 particles in aqueous medium showed that the hydrophobic interaction of CaCO3 and TiO2 especially the effect of hydrocarbon chains interweaving associating therein was the internal mechanism of firmly combination.The particles of TiO2 and CaCO3 succeed hydrophobic aggregation through three stages which contained particles surfaces hydrophobic regulation,particles approach by plus mechanical energy,particles hydrophobic aggregation and hydrocarbon chains interweaving associating.