Graphene
Size
1-2nm thick x 0.5-5microns wide
Package
According to customer requirements
Features
High strength, high electrical conductivity, etc.
Application
Can be used as filler(between 0.01% and 5%).
Graphene, as the thinnest, toughest and best conductive nano material found at present. It is a two-dimensional crystal composed of carbon atoms stripped from graphite material with only one layer of atom thickness. Known as “black gold”, it is “the king of new materials”. Scientists even predicted that graphene “will completely change the 21st century”.
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About graphene
Graphene is a kind of two-dimensional honeycomb carbon material composed of a single layer of carbon atoms. Its structure is stable, and it is the thinnest and hardest material in the world. Graphene has many unique properties, such as zero bandgap semiconductor properties, ultra-high Fermi velocity, carrier mobility, high thermal conductivity, good light transmittance, and excellent mechanical properties.
Graphene has room temperature quantum Hall effect and quantum tunneling effect. Therefore, graphene has wide application prospects in transparent electrodes, transistors, sensors, energy storage, high-strength composites, and so on.
In addition, it also has good biocompatibility, especially graphene oxide. It has broad application prospects in biology and medicine, such as targeted drug delivery, cell imaging, biological detection, tumor therapy, and so on.
Application of graphene in building waterproofing
As a new carbon nanomaterial, graphene has unique electrical, thermal, mechanical, and magnetic properties. It has a very wide application prospect in the field of building waterproof.
Xu Jiwu invented a kind of graphene waterproof coating. The product combines two functions of elastic waterproof and permeable waterproof. At the same time, graphene is added to the surface as a protective layer to realize three layers of waterproof protection. Graphene has hydrophobicity and ultra-long weatherability, which can realize the permanent waterproof protection of materials. The product has high permeability, high adhesion, high elasticity, high film-forming, and high weather resistance, and the construction technology of “four coatings and one cloth” can eliminate the need to solve the problem of mortar hollowing when using waterproof coiled material as a waterproof treatment for various complex cement matrix waterproof construction of buildings as mortar protective layer.
Liu Shao GUI prepared a kind of graphene waterproof and plugging coating with better performance than the existing waterproof and plugging coating by adding graphene nanosheets into acrylic latex powder. Graphene nanoflakes are connected with polymer molecules of acrylic latex powder by van der Waals force, which increases the crosslinking degree of polymer molecules of acrylic latex powder and the force between polymer molecules, thus significantly improving the bonding strength of acrylic latex powder. Therefore, the addition of graphene nanoflakes can reduce the amount of acrylic latex powder on the one hand, and on the other hand, it can play a synergistic role with latex powder, which is conducive to improving the overall bonding strength, compressive strength, flexural strength and impermeability of the product.
Hong Yue et al. Grown graphene on sapphire substrate by chemical vapor deposition (CVD) and studied the effect of growth time on the hydrophobicity and microstructure of graphene. It is found that the hydrophobicity of graphene increases with the growth time. This is because the longer the growth time, the lower the surface roughness of graphene, and the stronger the hydrophobicity. Therefore, graphene is expected to be used as a hydrophobic material to achieve self-cleaning function, even in the field of superhydrophobic applications. The following figure shows the contact angle of graphene surfaces at different growth times.
The contact angle of graphene surface at different growth time
Yin Yuhua and so on have synthesized a new environment-friendly eighteen amine graphene oxide modified waterborne polyurethane polyacrylate emulsion by the self-emulsifying method. It is found that the film prepared by this method has excellent self-healing ability, and its surface is smooth, hydrophobic, Young’s modulus and tensile strength are better than the conventional waterborne polyurethane polyacrylate emulsion. The following figure shows the self-healing properties of the films of waterborne polyurethane polyacrylate and octadecylamine graphene oxide modified waterborne polyurethane polyacrylate after new treatment and treatment for 20 days.
Self-healing properties of coatings
Zhang Youlai and so on synthesized a new type of osmotic composite emulsion with graphene oxide and isobutyl silane monomer by sol synthesis. The effects of graphene oxide/isobutyl silane composite emulsion, isobutyl silane emulsion, and graphene oxide dispersion on the permeability of concrete were studied by capillary absorption tests and capillary absorption experiments. It was found that the concrete coated with graphene oxide/isobutyl silane composite emulsion had the best waterproofing and chloride corrosion resistance.
Aiming at the defects of bubble and pinhole in polyurethane waterproof coating on the market, Keshun company takes isocyanate and polyether polyol as main raw materials, and adds graphene material in addition to special defoamer and filler, which significantly improves the density of coating film and extends the water permeability path of the coating film, The coating is still watertight under 2 times of water pressure of common polyurethane waterproof coating.
Effect of graphene on mechanical properties of one component acrylic waterproof coating
Styrene acrylic emulsion was used as the main film-forming material and graphene dispersion as a modifier. 400 mesh heavy calcium carbonate and 800 mesh talc powder were used as the main powder filler. The graphene-modified acrylic waterproof coating was prepared by grinding additives. The effect of graphene on the performance of acrylic waterproof coating was studied by changing the amount of graphene dispersion. The results show that the addition of graphene dispersion can significantly improve the mechanical properties and durability of the waterproof coating. When the addition of graphene dispersion is 3% of the coating system, the untreated tensile strength and elongation of the coating reach 2.47 MPa and 359% respectively, and the retention of tensile strength and elongation of the coating after treatment is more than 80%, It meets the requirements of JC / T 864-2008 standard.
