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Nanomaterials in rubber industry application

The development of the rubber industry is closely related to the use of nanomaterials. Rubber materials in the 21st century are developing towards high performance and functionalization. Usually, the composite obtained by adding nano powder into the rubber matrix is nano-rubber. The application direction of nano-materials in rubber can be summarized as two aspects: improving mechanical properties and providing some special functions (such as anti-aging, gas barrier and antibacterial).

The common nano powders used for rubber reinforcement and more special functions are mainly oxides nanoparticles, including zinc oxide nanoparticles, alumina nanoparticles, titanium dioxide nanoparticles and silica nanoparticles. Also there are other nanomaterials such as carbon nanotubes, silicon nitride nanoparticles, nano graphene, nano diamond, etc.

 

  1. The reinforcing effect of nanomaterials on rubber

The most used and most common reinforcing agent is nano sized silica (SiO2 nanoparticles). The application results of SiO2 in tire production are more reflected in the substantial improvement of the basic performance of tires.

Multi-walled carbon nanotubes (MWCNTs) can greatly improve the mechanical properties of composite materials due to their ultra-high strength, great toughness, and unique electrical and thermal conductivity. It is much better than carbon black in terms of wear and abrasion performance, which is beneficial to the development of low-rolling tire tread compounds.

 

  1. Nanomaterials can improve the vulcanization activity of rubber

Zinc oxide (ZnO) is an essential additive in the rubber and tire industries, and can be used as a vulcanization activator and reinforcing agent for natural rubber, synthetic rubber and latex, as well as a colorant. When nano zinc oxide is used as a vulcanization activator, compared with ordinary zinc oxide, the dosage can be greatly reduced. In the formulation of rubber shoes, active nano zinc oxide is an excellent inorganic active agent and vulcanization accelerator, which can significantly improve the performance of rubber shoes and prolong its service life. In addition, it can also be used as a sterilant, which can effectively inhibit the reproduction of bacteria. It is also a good UV shielding agent and anti-aging.

 

  1. Nanomaterials can improve the heat resistance of rubber

Nano silicon nitride (Si3N4) is a gray-white high-melting-point crystalline powder, which is a covalent bond compound, and the combination is very stable. It has high chemical stability, high temperature resistance and good wear resistance. Evenly dispersing it into the rubber matrix can significantly improve the service life of heat-resistant rubber products under dynamic conditions.

 

  1. Nanomaterials can be used to produce special thermally conductive tires

Graphene conductive tires can not only meet the high performance requirements of ordinary cars, but also can be widely used in inflammable and explosive goods transport vehicles, special vehicles for electronic equipment, special vehicles for military and police, etc.

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Modification of Epoxy Resin by Silicon Carbide Whiskers (SiC-W)

Because of the small diameter, large aspect ratio, high strength, high modulus and excellent heat resistance, silicon carbide whiskers play a unique role in the modification of polymer materials. Epoxy resin has been widely used in various fields of the national economy because of its high strength, good adhesion, good thermal stability, high strength, and small shrinkage. SiC whisker modified epoxy resin can further improve its mechanical properties (strengthening and toughening), friction and wear resistance and antistatic properties.

 

Epoxy resin (EP) is one of the most widely used thermosetting polymer materials. It has excellent adhesion, thermal stability, electrical insulation, chemical resistance, high strength, small shrinkage, and low price and it’s widely used in various fields such as coatings, adhesives, light industry, construction, machinery, aerospace, electronic and electrical insulation materials, and advanced composite materials. However, due to the shortcomings of epoxy resin cured products such as high brittleness, low impact strength, easy cracking, and poor antistatic performance, its further applications are limited.

 

Epoxy resin glue is prepared by epoxy resin plus curing agent, filler and so on. It has the characteristics of high bonding strength, high hardness, good rigidity, acid, alkali, oil and organic solution resistance, and small curing shrinkage. At present, the bonding strength of epoxy adhesive is relatively high, but there are still some deficiencies in the bonding of some high-strength structures, and the bonding strength needs to be further improved.

 

Whiskers are fibers with extremely small diameters grown in the form of single crystals under special conditions. They have a highly ordered atomic arrangement structure, so they can approach the theoretical strength of valence bonds between atoms, and have great potential for strengthening epoxy adhesives. Many research results show that filling whiskers into epoxy resin matrix can effectively solve these shortcomings and greatly improve the comprehensive performance of epoxy resin.

 

Silicon carbide whisker is a cubic whisker whose crystal form is the same as that of diamond. It is currently the whisker with the highest hardness, the largest modulus, and the best heat resistance among whiskers. The crystal form is β-type, which has higher hardness, better comprehensive properties such as toughness and thermal conductivity, and is also one of the best reinforcing and toughening materials. It can significantly improve the toughness, flexural strength, hardness, wear resistance, and high temperature resistance, oxidation resistance, thermal conductivity, structural stability, thermal shock resistance, etc..

 

The silicon carbide whiskers treated with the coupling agent can be well and stably dispersed in the matrix, the whiskers are well infiltrated by the matrix, and the interface bonding strength is increased. Through this interface, the matrix and whiskers are connected as a whole. When the matrix is ​​subjected to external force, the stress can be uniformly transmitted through this interface and absorb a large amount of energy. On the one hand, when a crack appears in the matrix, the whiskers bridge the surface of the broken crack, which can hinder the further development of the crack; on the other hand, if the crack encounters silicon carbide powders, if it wants to develop further, the crystal must be destroyed or removed. Whiskers have high strength and high modulus, and it takes a lot of energy to destroy or pull out the whiskers, and when the crack bypasses the whiskers, it develops further and causes more microcracks. And because the whiskers have a relatively large L/D, more energy needs to be absorbed, thereby significantly increasing the strength and toughness of the EP matrix.

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Dispersion method of nano silver powder

Because of the volume effect, surface effect, quantum size and other effects unique to nanomaterials, nano silver powder has many special uses. In the field of antibacterial medicine, silver nano particles are more likely to be in close contact with pathogenic microorganisms, thereby exerting greater biological effects. It has the characteristics of wide antibacterial range and long duration, and is a new type of nano material with broad application prospects.

 

Nanopowders have small particle size and high surface activity, and it is easy to agglomerate between particles. Ag nano powder is no exception. The agglomeration will affect the development and application of nano Ag particle and its derivatives. The key technology is solve the agglomeration and obtain a stable dispersion. In order to obtain nano silver materials that are compatible with the process formula and are easy to disperse, please refer to the following points:

 

  1. If the user is willing to provide the application details, Hongwu Nano can modify the silver nanowires in advance to improve the dispersion of silver accordingly.
  2. In general, the addition of surfactants and mechanical dispersion methods should be combined to achieve good dispersion effects.
  3. Commonly used mechanical dispersing equipments include: generally used in low viscosity systems such as water and organic solutions, high-speed dispersing machines and ultrasonic equipment can be selected. High-viscosity system (paste) can be selected pulp mill, surface mill, high-speed dispersion disc, ball mill, etc..
  4. The dried silver powder can be depolymerized and surface modified with a supersonic jet mill.
  5. Commonly used surfactants: polymer surfactants such as PVP, gum arabic, polyethylene glycol, polyvinyl alcohol, etc. These dispersants are recommended for water-based systems. Surfactants can be used in combination and can significantly improve the dispersion effect.
  6. Based on years of silver powder production experience and users’ feedback, Hongwu Nano has summed up practical nano silver powder dispersion methods and techniques. Currently we can provide untreated nanosilver powder, surface-modified nano-silver powder, nano-silver water dispersion(colloidalAg), etc. Tailor-made nano-silver series products according to customer requirements.
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Summary of the various applications of nano graphene on mobile phones

Graphene nanopowder  is a two-dimensional material. Carbon atoms are arranged in a hexagonal shape and are connected to each other to form a carbon molecule. Its structure is very stable. As the number of connected carbon atoms increases, the two-dimensional carbon molecule plane keeps expanding, and so does the molecule. A single layer of graphene nanoparticles is only one carbon atom thick, that is, 0.335nm, which is equivalent to 1/200,000 of the thickness of a hair. There will be nearly 1.5 million layers of graphene in 1 mm thick graphite. Graphene is the thinnest known material and has the advantages of extremely high specific surface area, superior electrical conductivity and strength. The existence of the above advantages is that it has a good market prospect. Various applications of nano graphene on mobile phones are as follows:

 

Screen

Graphene screens can use force sensors, bringing a new dimension to touchscreen technology. Furthermore, thanks to graphene’s high toughness, these new properties can be integrated into flexible screens, which are useful for wearable technology.

 

Phone case

Graphene is a high-strength material. Mixed with resins and plastics, or even just as a coating, graphene could be used to make safer helmets, stronger aircraft parts and more durable building materials. Combining graphene with a phone’s case could make it even stronger, and we might never have to worry about it falling off again!

 

Antennas and Communications

Graphene could boost optical data communications to unprecedented rates while reducing energy consumption and transmission errors. By 2020, the graphene flagship aims to link more than 400 gigabits of data per second. Graphene can also serve as the basis for flexible near-field communication (NFC) antennas, enabling new technologies such as electronic banknotes or smart wallets.

 

Sensors

Graphene sensors have many applications: linking to health sensors throughout our bodies, monitoring high-risk infections, oxygen and sugar levels, correcting our posture, and even helping us track neurological pathologies. Sensors can also detect and analyze our environment.

 

Processors and Electronics

Graphene’s electronic properties allow us to make faster and more reliable phone accessories. Graphene has high strength, conductivity, yet thin — just one atom thick, enabling thinner and faster microprocessors for smart products and the Internet of Things. Graphene and related materials are so flexible that devices can be integrated into textiles or even ‘stickers’ directly on the skin.

 

Battery

Graphene can be used to improve the capacity, efficiency and stability of batteries. Graphene batteries can have higher energy storage and better performance in terms of service life and charging time. Graphene and related materials can also be used to improve the performance of other energy storage solutions, such as supercapacitors. Another role of graphene in graphene-based lithium-ion batteries is to improve heat dissipation.

 

Headphones/Speakers

Graphene could make headphones and speakers more energy-efficient and lighter, while producing better sound. As membranes become lighter, they are often too FL releasable and generate unnecessary vibration and noise. Graphene is flexible and strong, so distortion is reduced and people can enjoy their favorite music sources with unprecedented clarity!