Ramkumar of Texas University of Technology believes that nanomaterials will be the future trend in the production of nonwovens. They believe that nonwovens products will play a role in the development of nanotechnology silently. In 1934, the patented cellulose acetate electronic spinning technology was generally regarded as the foundation of nanotechnology. Green Screen,Key Chrome Green Screen,Portable Floor Green Screen,Chroma Key Green Screen Background Dongguan Aoxing Audio Visual Equipment CO.,Ltd , https://www.aoxing-projectorscreen.com
Nanotechnology was first applied in the electronics industry, but the textile industry has adopted it lately. Donaldson's nanofiltration equipment and Nano-Tex waterproof splash fabric are industrial products that enter the market in small quantities. According to Donaldson personnel, about one-third of all its products contain certain nanomaterials. So far, more than 100 colleges and industrial research units around the world are engaged in the exploration of nanofibers, textiles and polymers. Some governments have invested heavily. According to the National Science Foundation, they invested in nanotechnology in 2005 More than 4 billion US dollars. The United States, the European Union and Japan are ahead in this regard, and there have been some interesting developments in fiber and textile nanotechnology in recent years.
Nanofibers
The nano-scale fiber products developed by the laboratory have the advantages of large specific surface area, flexibility, air permeability, microporous structure, light weight, high Young's modulus and good functionality. At present, there have been a few successful batch applications. Such as filters, lining layers of chemically resistant fabrics, tissue scaffolds, and some high-end engineering applications. Generally, fibers with a diameter of 100-500 nm are regarded as nanofibers.
The electronic spinning method invented by Anton Formhals in 1934 is the pioneer of today's nonwoven nanofiber electronic spinning. Electronic spinning is a charged nozzle that uses a high-voltage electric field to spin a polymer solution and form a nanofiber web after the solvent is evaporated and dried. In a strict sense, nanofibers are non-woven fabrics of sub-micron fibers. Depending on the end use, various polymers, such as natural, synthetic, and biodegradable polymers, can be easily made into nanofiber webs using electronic spinning. Due to the work of Professor Reneker of Akron University, a wave of nanofiber spinning emerged in the 1990s. Doshi pioneered nanotechnology company eSpin Technologies Inc. in Tennessee to mass-produce electronically spun nanofibers using a variety of polymers.
The Massachusetts Institute of Technology (MIT) 's Rutledge Group conducted basic research on electronic spinning, and decided that a certain polymer can spin the terminal nozzle diameter of the corresponding fiber diameter.
Used in military industry
In addition to being used in filtration equipment, functional nanofibers are valued in military research and development due to their potential resistance to chemical and biological weapons. In order to protect the soldiers from poison and provide the necessary comfort, nanofibers are very useful. The nanofiber lining anti-biochemical military uniform is light in weight, breathable, wide in function, good in anti-chemical performance, and can defend against toxic liquid, vapor and smoke.
The American Natick Military Center collaborated with the government, industry, and universities to explore the practical application of nanofibers and nanoparticle materials in protective clothing. There are some encouraging topics, such as the electronic spinning fabric of thermoplastic elastic polyurethane, which has good performance; it has high elasticity and does not require further processing or treatment, and the strength is higher. The current tests and developments are focused on functional melt-blown and electronic spinning; mixed with nano-scale aluminum and titanium materials to make mesh, and then combined with other methods to add reactive compounds to the fabric to obtain self-decontamination performance.
The addition of functional nanofiber mesh materials with other materials can increase its application value. Nanofibers embedded with metal oxides can catalyze organic phosphorus chemical weapon agents. Recently, Texas Tech University successfully buried magnesium oxide (MgO) in polymer fibers. By carefully controlling this process, nanoparticles can be deposited on the surface of the fiber to make it have maximum chemical reactivity and provide better anti-toxic function. . Electronic spinning technology can be effectively used to develop honeycomb filter-in-filter polyurethane nanomesh. These filtering equipment can provide filtering ability due to the nano mesh to better capture particles.
The National University of Singapore Ramakrishna Group and the National Defense Science and Technology Agency (DSTA) have collaborated to develop a nanofiber biochemical mask that can replace activated carbon with nanofiber mesh to trap poisons in the air. Fiber to break down chemical poisons. The initial test of "paraxon" with chemical weapon simulants was successful. The ultimate goal is to develop a nanofiber military uniform that can be washed and durable.
At the same time, Professor Rutledge and his assistants at MIT developed super-hydrophobic e-spun nanomaterial fabrics, which are affected by the chemical and morphological characteristics of the fiber surface. use.
TANDEC of the University of Tennessee, etc., added nanophase Mn (Vâ…¡) manganese oxide (M-7-0 agent) as a defense material to the nonwoven fabric. Agent M-7-0 is an environmentally friendly material and belongs to Lewis strong acid oxidizer. It is said that the main advantage of this type of non-woven fabric is that it can be safely transported, and it can be made into materials with different shapes, good flexibility, chemical weapons, chemical stains and industrial toxicity according to the end use.
Applied in biomedicine
Professor Freg and his assistants at Cornell University have developed biodegradable polymers with high specific surface area and hydrophilic materials, which can be used as biosensors for drug delivery and pesticide delivery. According to Freg, the high specific area of ​​nanofibers has many receptor active sites in small volume fibers.
Donaldson is in the forefront of nanofiber mesh biomedical applications and has been in the nanofiber business for more than 20 years. In 1981, its Ultra Web nanofiber filtration equipment was industrialized and has expanded into new applications, such as nanofiber cell culture materials and smoke barrier clothing. In 2002, Donaldson established a new group to focus on new application fields of nanofibers, and encouraged cooperative research partners to joint ventures to expand batch applications; recently developed three-dimensional cell culture media to simulate extracellular matrix (ECM) in vivo. Biodegradable nano-mesh, because it is similar to extracellular matrix, can be used as tissue scaffold. Such scaffolds bring cells close to each other and grow into a three-dimensional organization. The key factors are mechanical stability, biocompatibility, cell proliferation ability and cell-matrix interaction. These determine the application of nanofibers in biomedicine.
latest progress
Recently, there is a huge interest in nano-scale spun-melt fibers. Hills has used the sea-island method to study homogeneous melt-spun fibers with a diameter of 250 nanometers. According to its claim, the fiber strength can reach 3 g / denier and can be wound for further processing in downstream processes. Hills has developed 2-0.3 micron sea-island fiber spunbond fabrics; it has also been successfully produced using the island-sea method Nanotubes with a diameter of 300 nanometers and a wall thickness of 50-100 nanometers have been patented. Hills' nanotube fibers can be used to defend against chemical weapons, drug release, micron-scale filtration and micron-scale hydraulic equipment (hydraulic devices).
Sumio Ijima, a laboratory of the Japan Electric Power Company (NEC), developed multilayer carbon nanotubes in 1991. It is characterized by light weight, high strength, good electrical properties and heat resistance. Scientists at the NanoTech Institute of the University of Texas (UTD) in Dallas, USA, and the Commonwealth Scientific and Industrial Research Organization of Australia (CSIRO) have made great breakthroughs in spinning multi-layer carbon nanotube yarn technology. , Extremely soft, conductive heat transfer, can be made into "intelligent" clothing, energy storage, bulletproof, temperature adjustment, porous, very comfortable to wear.
Non-woven fabrics have huge application prospects
One of the reasons for the failure to popularize the industrialization of electronic spinning technology is that it is still difficult to buy industrial-scale machinery and equipment. NanoStatics of Ohio has developed high-yield nanofibers and electronic spinning machinery manufacturing technology containing nanomaterials that reach industrial scale. NanoStatics electronic spinning technology can normally produce fibers with a diameter of 50-100 nanometers, and the thickness of its nanomesh can be in the range of 100 nanometers to 200 micrometers, and it has the conditions for investment and production.
Zurich's scientific management consulting company ACON, AG estimates that the global nanotechnology market will reach US $ 90 billion in 2015. The large-scale adoption of nano-fiber non-woven products will help non-woven production and the textile industry to explore a variety of high-value-added applications and use nanoscience to expand its market share. Fundamental business and collaborative research in industry will make nonwovens dedicated to the future molecular-level technology to achieve a win-win situation.