Singapore scientists to convert waste tire rubber as a multi-purpose airgel
In addition to daily hear the \”white pollution\”, in addition to \”color pollution\” – scrap textile pollution, \”black pollution\” – pollution rubber tire. Each year, the world produces about ten one hundred million discarded tires, rubber tires, although very durable, but once the waste can not be biodegradable. Currently, only 40% of scrap tires is recovered to a low value-added products; 49% is incinerated, the combustion of rubber but may produce toxic substances, hazardous to health and safety; and 11% was filled in a landfill however, unsustainable, because the landfill has run out, but also on the environment and land leachate generated causing serious pollution. 
Although 40% of waste rubber tires to be recycled, but the recovery of the world remains low, because the high cost of processing the waste tires and large energy consumption. Today, waste tire processing has become a worldwide problem. airgel huge potential market, to 2022, the global automotive thermal and acoustic insulation solution market is expected to reach $ 3.2 billion; Professor senior management members of the global oil market research group Nhan Phan-Thien added: \”by 2025, this figure is expected to reach $ 182.7 billion.\” recently, affected by the current market and the potential environmental problems, National University of Singapore Duong Hai-Minh associate professor for the first time successfully scrap tires into rubber airgel . The waste tire of automobile tires regenerated fibers (RCTF) successfully produced a new type of rubber as airgel, and a comprehensive study of the morphology and properties, has excellent heat and sound insulation, and oil absorbency. Meanwhile, the rubber airgel manufacturing process is simple, easy to scale up for mass production. These excellent properties make the airgel rubber products become commercially attractive, has the potential applications in high-value engineering.
Manufacturing Researchers first original RCTF made finer fibers; press RCTF (1.0μg), PVA solution (10μmL, 0.05μg / mL), the proportion of GA solution (50μL, 25%) and H2O (80μmL) mixing ultrasound; and the mixture is cured at a temperature of 85 ° C; and finally by freeze drying to obtain a rubber airgel. ThatRubber airgel manufacturing process is simple, cost-effective and environmentally friendly, The entire production process takes 12 to 13 hours, producing an area of 1m 2 , only the thickness of the rubber airgel 1cm less than 50 yuan, it can be easily scaled up for mass production. 
The rubber airgel structure and morphology
and show a rubber RCTF airgel resulting from waste tire rubber can be seen that the airgel very soft. Panel d show reaction mechanism, added during preparation of the polymer PVA and PVA fibers hydroxyl group formed hydrogen bonds between chains; GA contribute to forming an acetal bridges between the polymer chains and the PVA oxide groups, further enhance the strength of the rubber airgel
oil absorption
the rubber airgel has a characteristic of low density and high porosity, which is due to surface diffusion RCTF PVA / GA crosslinking agent to form an acetal and an ester bond, thereby producing a porous structure. This highly porous features make good clear oil spill absorbent, the absorbent is twice that of a conventional absorbent, oil spills can be completely absorbed within a few minutes in the rubber airgel.
sound absorbing performance
Researchers rubber airgel having larger fiber contact and the area of fiber entanglement, the surface frictional resistance, sound waves propagating energy loss, loss due to internal friction and a large number of internal reflections will increase caused, and therefore increase the absorption of sound. The rubber airgel higher than the effect of 27% commercial absorbent foam of the same thickness.
heat-insulating properties
in fire protection applications, practical compartments hot material is required to have high thermal stability. The airgel rubber having high heat resistance, heat transfer limit a thickness of one inch (2.54 cm) rubber 25 corresponds airgelStandard glazing glass, used in the field of fire protection can be satisfied.
high endurance
Aerogels are most very brittle and fragile, but after the compression of the rubber airgel can spring back to its original shape, rather than plastically deformed, indicating that they have good durability. The unique properties make it suitable for use as insulating material in various fields, industrial fields such as refineries, and other industrial buildings, areas of daily life, such as refrigerators, shoes, clothing and the like.
by the National University of Singapore Duong Hai-Minh, and Associate Professor Professor Nhan Phan-Thien first team led discarded car tires rubber fibers cut into thin. The fiber is then dipped into a solution that consists of water and a small amount of \”eco-friendly\” solvent composition in which the fibers crosslinked with each other. The mixture was mechanically stirred for 20 minutes to form a gel, wherein the fibers are connected uniformly suspended therein. The gel was then poured into a mold, and freeze-dried at a temperature of -50C (-58F) 12 hours. The resulting solid rubber was alleged airgel very lightweight, high-absorbency (oil absorption can be used), and provide excellent thermal and acoustic insulation properties. Further, with conventional airgel different fragile, the airgel is considered to have high durability. If coated with a chemical called methoxy trimethylsilane, may also make it waterproof. 
Hai-Minh said: \”The manufacturing process is simple, cost-effective and environmentally whole production process takes 12-13 hours to complete, producing a size of 1 m2 and the cost of the rubber airgel less than 1 cm thick. 10 new currency. the process also can be easily scaled up for mass production, which makes rubber products aerogels become commercially attractive. \”in this article, the researchers developed a new type of cost-effective rubber airgel manufacturing technique, the first successful airgel scrap tires into rubber, and passed the test performance of thermal insulation, sound insulation, and oil absorption and the like, and the gas from cellulose / cotton / plastic as raw materials developed the same gel properties. we believeProcessing, this technology will waste tires provide a new method, and is expected to promote other types of waste into the technological development of the airgel.
