A chemistry professor at Thiagaraja Engineering College, India, has discovered that a combination of hot bitumen and molten plastic waste could be the way to solve the twin problems of battered roads and plastic waste. Civic bodies in and the highway department of Tamil Nadu state have already laid more than 750 km of plastic roads, and are adding more based on the process developed by Prof. R. Vasudevan. It is a simple procedure wherein plastic waste is mixed with hot bitumen before it is laid. Plastic waste like cups, carry bags and so forth are heated up to 170C to form a molten paste and get mixed with the bitumen, said Prof. Vasudevan. As the waste is not incinerated, which happens at 690C, no toxic gases are released. The process uses only non-chloride polymer waste to avoid chlorine seepage into the ground.

Adding plastic reinforces a road in three ways. It increases the roads load-bearing capacity, makes it more resistant to heat (especially during summers) and prevents rainwater from seeping down. The third factor ensures durability, since water is the main enemy of bitumenized roads. Performance studies on the roads built with plastic waste indicate satisfactory performance with good skid resistance, good texture value, stronger and less amount of progressive unevenness over a period of time, state the guidelines issued by the National Rural Roads Development Agency, an arm of the Union Rural Development Ministry. The Ministry recommends the use of polyfilms with thickness up to 60 m, hard and soft foams, and laminated polymer with thickness up to 60 m. However, polyvinyl chloride sheets should not be used.
Source: www.telegraphindia.com

2K Manufacturing, the United Kingdom, is setting up a new factory that turns mixed plastic into a composite board called EcoSheet. The board has been tested by Bovis, a construction company supporting the project. EcoSheet costs about the same as plywood and, like plywood, can be used to build a variety of things such as advertising hoardings, flooring and shuttering used to contain concrete. It has several advantages over plywood: it is more easy to work with as it does not produce splinters; it does not rot; and unlike plywood it can be recycled, even if it is painted and full of nails.

2K Manufacturings production process uses a form of encapsulation called powder-impression moulding. The plastics are grind-mixed into powdery flakes, spread over a polymer skin, covered with another skin, and then sintered. During the process, air is blown through the sandwich to create a spongy core. Once the material cools and hardens, it acquires mechanical strength from its composite structure.
Source: www.economist.com

In the United States, Envion Inc. is leading the charge towards a green future with the introduction of a revolutionary plastic-to-oil conversion technology. The Envion Oil Generator (EOG) is a first-of-its-kind technology that converts any type of plastic waste into high-quality, synthetic oil for less than US$10 per barrel. Envion has already de-monstrated its first commercial unit.

Being a petroleum-based product, plastic contains a huge amount of stored energy that literally goes to waste with conventional disposal methods. Envions technology reclaims that energy and provides it as oil, which is immediately commercially viable. Through Envions proprietary technology, 1 tonne of waste plastic can be converted into approximately four barrels (159 litres each) of high-quality, synthetic light to medium oil. This oil is a refined and 99 per cent sediment-free product that can be used to produce petroleum, diesel fuel, jet fuel and kerosene. EOG uses a closed-loop, catalyst-free system. Each individual unit can process up to 10,000 t/y of plastic waste. Contact: Environ Inc., 1027, 33rd Street N.W., Washington, D.C., 20007-3529, United States of America. Tel: +1 (202) 965 5030; Fax: +1 (202) 965 5032; E-mail: info@envion.com.
Source: www.reuters.com

Researchers in China have developed a technique that uses waste plastics as the carbon source for synthesizing silicon carbide (SiC) nanomaterials. This development may provide an effective method to help solve the environmental pollution of waste plastics. SiC is a useful functional ceramic material with excellent mechanical properties, high physical and chemical stability, and high thermal conductivity. Generally, it is used in abrasives and the metallurgical and refractory industries.

According to Dr. Zhicheng Ju of the School of Chemistry and Chemical Engineering, Shandong University, We have used three typical kinds of plastic wastes (HDPE, LDPE and PET) as carbon source, although other types of waste plastics may also be used as carbon source to prepare SiC or other carbide nanomaterials. The researchers produced SiC nanomaterials by using these plastic wastes together with silicon powder, sodium, magnesium and sulphur powder as reactants in an autoclave at 350-500C where the reaction pressure is usually not more than 10 MPa. They cleaned and treated the products of the preceding step by a refluxing process with aqueous perchloric acid and a mixture of hydrogen fluoride and nitric acid, respectively, to obtain the pure SiC powder. The X-ray powder diffraction has shown that the samples from HDPE and LDPE are all highly crystalline 3C-SiC while the sample from PET was 3C-SiC with a small amount of 2H-SiC. The average SiC yield is 39 per cent based on the amount of Si powder.
Source: www.nanowerk.com

RubGreen LLC, a start-up company in the United States, is using a new technology to produce higher quality secondary rubber from devulcanized rubber crumb. The technology has proven to be economically viable and represents a breakthrough approach to efficient rubber recycling.

Independent test results have demonstrated that secondary rubber made from 100 per cent unsegregated tyre rubber crumb using unoptimized equipment consistently provides 1,200-1,400 psi of tensile strength and 250-300 per cent of elongation. These results would be substantially improved under industrial settings. Validation and testing of RubGreen technology were conducted at three testing facilities Smithers Scientific Services Inc., the United States; Deutsches Institut fur Kautschuktechnologie e.V., Germany; and Partec-Plastics and Rubber Technical Education Centre, Australia.
Source: www.azom.com

Researchers in Japan have patented a method for recycling plastic reinforced with carbon fibres and a thermoset resin (epoxy resin). The end product is a recycled material having excellent strength properties. First, the fibre-reinforced plastic material is heat-treated to totally burn off the epoxy resin to produce a harmless material. Next, a sizing agent is applied to or sprayed over this harmless material to produce another material in the form of strips. A recycled material having short carbon fibres is produced when the strip-form material is kneaded with a thermoplastic resin (polypropylene). Contact: Toyota Jidosha Kabushiki Kaisha, 1, Toyota-cho, Toyota-shi, Aichi, 4718571 Japan.
Source: www.wipo.int

Polystyrene, used widely as packing material or insulating material, is difficult to recycle and typically ends up in landfills. Various esters of biogenic oil fatty acids (such as methyl soyate, the methyl ester of soybean oil) can be a very strong solvent for polystyrene, according to research by Missouri University of Science and Technology, the United States.

The University researchers have prepared methyl soyate solutions containing 80 per cent by weight of scrap polystyrene. The researchers then polymerized these mixtures to obtain useful resins for composite materials as well as coatings for explosives. The compositions can also be employed in forming an improved polyester, according to the research report. Contact: Mr. Keith D. Strassner, Director, Office of Technology Commercialization and Economic Development, Missouri University of Science and Technology, 203 Centennial Hall, 300 W. 12th Street, Rolla, Missouri, MO 65409-1110, United States of America. Tel: +1 (573) 341 4690; Fax: +1 (573) 341 6579; E-mail: kdstrass@mst.edu.
Source: www.ibridgenetwork.org