NanoCalcium carbonateRefers to the particle size of 1 ~ 100nmCalcium carbonateProducts, including ultra-fine and ultra-fineCalcium carbonatetwo products. NanoCalcium carbonatesmall size effect, surface effect, macroscopic quantum tunneling effect and quantum size effect, which has become a research hotspot in recent years.
NanoCalcium carbonatesurface modification method
local chemical reaction modification
Local chemical reaction modification is the first addition of treatment agents (coupling agents, organic, inorganic, etc.), and then nanoCalcium carbonateA method in which surface functional groups chemically react with it to achieve the purpose of modification.Currently NanoCalcium carbonateThis method is the most widely used surface modification.
The local chemical reaction modification process is mainlydry methodandwet methodTwo kinds.
The dry method is to add nano in turn to the modifier.Calcium carbonatePowder and surface modifier, surface modification.
Suitable for surface modification with coupling agents.
Advantages:The operation is simple, the production cost is low, and the material can be directly packaged and transported.
Disadvantages:The surface uniformity is not good, and due to the limitation of domestic coupling agent development and application technology, it has a certain impact on its practical application.
The wet method is adopted in the nanometer.Calcium carbonateA modifier is added to the solution for surface modification.
surface coating modification
NanoCalcium carbonateA modification method in which both particles and coatings are connected by van der Waals forces or physical methods. The surface modifier or hyperdispersant is added to the nano.Calcium carbonateIn the preparation of the solution, in the production of nanoCalcium carbonateAt the same time, the surface modifier is coated in.Calcium carbonatesurface, so that the final product in the form of uniform particles.
in the nanoCalcium carbonateThe surface is coated with a layer of inorganic silica, so that it has the properties of silica to a certain extent, surface smoothness, whiteness, heat resistance, acid resistance, dispersion, specific surface area, oil absorption value, etc. are greatly improved, greatly improvedCalcium carbonateapplication performance. Surface coating modification to improve nano.Calcium carbonateThe dispersion is very effective, but also improves the surface properties of the particles, but the thickness of the coating is not easy to control, is an important problem to be solved in the actual operation.
Masterbatch filler modification
Masterbatch filler is a new type of filler, by a certain proportion of resin masterbatch,Calcium carbonateand surfactant mixing to produce a masterbatch filler at the same time.Calcium carbonateSurface modification was performed. Depending on the matrix resin used, the common masterbatch fillers are mainly polyethylene wax.Calcium carbonateMasterbatch, random polypropyleneCalcium carbonateMasterbatch (APP masterbatch) and resinCalcium carbonateMasterbatch filler, etc.
Segment with several composite modifiers, polyethylene masterbatch to nano.Calcium carbonateThe results show that the effect of oleic acid-maleic anhydride compound modifier is the best, and the whiteness value and mechanical properties of the polymer material are greatly improved.
Masterbatch filler modification coating uniform and complete, modified.Calcium carbonateThe compatibility with the composite material is good, the mechanical properties of the product are also improved, and the operation is simple and convenient, but the current type of masterbatch filler is limited, which limits the wide application of this method.
High performance surface modification
A method of modification using plasma or high-energy rays (e. g., X-rays, gamma rays, etc.). Plasma for CaCO3The surface modification of the powder is mainly the use of plasma polymerization technology, first of all, the monomer activation to produce gas phase radicals, and then adsorbed on the solid surface to become surface radicals, and then with the plasma or gas phase of the original monomer polymerization reaction, in.Calcium carbonateA polymer film is formed on the surface to achieve modification.
First of all, the surface of the particle is activated by mechanical force, so that the crystal structure of the surface is changed and the crystal lattice is moved, so that its reactivity with inorganic or organic substances is enhanced to achieve the purpose of modification.
to nanoCalcium carbonateFor the modifier, the heavy mass is used by mechanical chemical method.Calcium carbonateconducted surface modification studies, compositeCalcium carbonateThe particle size is fine and uniform, the whiteness value, specific surface area and oil absorption are improved, and the sedimentation performance is obviously improved.
The mechanical chemical modification method has low technical requirements, simple equipment and low cost, but it is only suitable for CaCO with large particle size.3For nano-CaCO with smaller particle size3, the effect is not good. But the use of this method can make CaCO3The increase in the number of active groups and active points on the surface enhances its effect with the modifier, so it can be considered that this method and other modification methods are combined with nano-CaCO.3Surface modification was performed.
NanoCalcium carbonateThe particle size is nano, the surface properties are complex, the modification mechanism of various modification methods is different, the advantages and disadvantages are different, the actual operation should be based on the specific situation to choose the appropriate modification method or a variety of methods combined use, in order to achieve the ideal modification effect.