Keychain technology in nano applications solves the problem of dispersion and prevention of agglomeration of nanoparticles
Close chain technology in nano applications solves the problem of dispersion and prevention of agglomeration of nanoparticles. Due to the high surface activity of nanoparticles, agglomeration is easily caused, thereby losing the performance of nanoparticles. How to prevent aggregation of nanoparticles and how to ensure that the polymer is Nanoscale dispersion is a technical difficulty in preparing nanopolymers.
Generally, nanoparticles use organic substances (such as surfactants) to treat their surfaces. There are two methods with obvious effects in nanotechnology polyurethane elastomer materials: one method is called in-situ polymerization method. Surface-treated nanoparticles are added to the monomer, and then the monomer polymerization is initiated to achieve nano-modified polymers. Purpose. Then the silica gel is divided into nano-SiO2, and this process is combined with the polyester polyol synthesis process to produce nano-polyester polyol. High-performance nano-modified spandex can be produced using this nano-polyester polyol raw material. (Including dry method and melt spinning method)
Intercalation lamination nanotechnology is to insert monomers or polymers between layered inorganic sheets, and then peel off the sheet structure matrix elements with a thickness of 1nm and a width of about 100nm, so that they can be evenly dispersed in the polymer among things. This enables the bonding of polymers and inorganic layered materials at the nanoscale. This kind of nanotechnology has been successfully studied in the application of dry spandex by researchers Sun Xianyu and Kong Kejian of the Institute of Chemistry, Chinese Academy of Sciences, and Professor Wu Jinwan of the School of Chemistry and Molecular Engineering of Peking University, and has obtained a creation patent.
The invention uses inorganic layered nanomaterials such as aluminum silicate montmorillonite (MMT) and magnesium aluminum salt hydrotalcite (LDHS). First, the nanomaterials are subjected to organic surface treatment to prevent nanomaterials from agglomerating. The interlayer spacing of untreated montmorillonite is about 1nm, and the lamellar area reaches several microns due to folding and accumulation. After organic treatment, the interlayer length is 1.9nm, and the lamellar area reaches 200-300nm. The organically treated nano-montmorillonite is introduced into the chain extender component in the manufacture of spandex. Due to the reaction between the chain extender and the prepolymer, a large amount of heat is generated to spread the sheet. After the chain extender monomer molecules are introduced, the montmorillonite surface The spacing between the layers was expanded to 2.7nm, and the area of the lamellae was further reduced to tens of nanometers due to the cracking effect. This achieves nanoscale dispersion of montmorillonite layers in the polymer matrix. Hydrotalcite has the same process and effect, but the spacing between hydrotalcite layers is significantly larger than that of montmorillonite.
This kind of nano-spandex fiber laminated by spandex fiber PU material and layered nano-materials can give full play to the small size effect and surface effect of nano-materials; it shows super surface properties and physical cross-linking effects; To increase the force between polymer chains and improve the crystallinity of the spandex PU soft segment, so that the spandex fiber has higher mechanical properties and good fire protection, bacteriostasis, mildew resistance and excellent chlorine resistance.
Intercalation nano-lamination technology, in theory, is also suitable for melt-spun spandex.
Summary:
Nano intercalation lamination technology has greatly improved the comprehensive performance of dry spandex. Among them, the improvements in elongation at break, wire strength and chlorine resistance are more prominent. This is an effective technical way to improve and improve the quality of spandex.
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