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The recycling of plastic that used to end up in landfills in the city or incinerators increases worldwide Like any technology trend, the engineering profession is important plastic discarded products and packaging are a increasing share of MSW municipal solid waste environmental protection Agency EPA estimates that by 2000, the amount of plastic throw will be 50 percent more than in early 1990, EPA also indicates that the plastic waste accounts for about a fifth of all waste in the waste stream over the past two decades, the recycling of plastics has increased dramatically after years of predictions that the recycling of plastics will would never spread because the processes were inefficient, too expensive or not practical, the tide of waste going to the a discharge is slowly turned.
Plastic term is used to describe a wide variety of resins or polymers with different characteristics and uses of the polymers are long chains of molecules, a group of several units, taking its name poly Greek means many and meros means parts or units.
The polymer is often used synonymously with plastic, but many other types of organic and inorganic molecules are also polymer Although all plastics are polymers, all polymers are plastic polymers are rarely useful in themselves and are often modified or blended with additives including colors to form useful materials the compound produced is usually called plastic most people have little contact with polymers because most of the items they encounter are actually modified and colorful and so are actually plastic polymers can be classified in several ways, depending on their make and are developed for this discussion on recycling, understanding the two types of polymers is useful.
Thermoplastic polymers can be heated and formed, followed by heating and formed again and again the shape of the polymer molecules are generally linear or slightly branched This means that the molecules can move under pressure when heated above their point of fusion.
thermosetting polymers undergo a chemical change when heated, thereby creating a three-dimensional network once they are heated and formed, these molecules can not be re-heated and re-formed.
Comparing these types thermoplastics are much easier to adapt to recycling.
When working with plastics, it is often necessary to identify the particular plastic was used for a product Most consumers recognize the types of plastics by the digital coding system created by the League of plastics industry in the late 1980s There are six different types of plastic resins that are commonly used to pack household goods the identification codes listed below are located on the bottom of most plastic packaging.
PETE Polyethylene terephthalate - PET Soda water containers, some waterproof packaging PET recycling water is similar to polyethylene PE bottles can be sorted by color and are crushed and washed Unlike polyethylene, PET flows into the wash water while the plastic caps and labels float off the clean flakes are dried and often repelletized.
Recycled PET has many uses and well-established market for this useful resin by far, the largest use is in textile carpet companies can often use 100 recycled resin for the manufacture of carpet Polyester in a variety of colors and PET textures is spun like cotton candy makr filling fibers for pillows, duvets and PET jackets can also be ito clear or rolled strip sheets for VCR and also audio tapes, a significant amount back on the market the bottle.
HDPE HDPE - milk, detergents, oil bottles, toys and plastic bags HDPE is called natural since it is the natural color, and it is the most valuable because it can be transformed into a color when it is recycled other products are often packaged in bottles to whiched bright colors mixed with recycling plants in colored balls or rainbow mixed most of this material is later dyed black after treatment.
HDPE recycling is a fairly simple process aprt balls are broken and ground into small flakes These flakes are then washed and floated removed and heavy contaminants unsinkable This flakes cleaned is then dried in a hot air stream and can be packaged and sold in this form more sophisticated plastic plants can heat the flakes, add a pigment to change the color and run the material through a pelletizer This form of little plastic beads material which can then be reused in injection molding machines to create Some new products end uses for recycled HDPE pipes are plastic, wood, flower pots, garbage cans or bottles formed in prior non-food application.
V vinyl PVC polyvinyl chloride - food packaging, vegetable oil bottles, blister packages.
LDPE Low Density Polyethylene - Many plastic bags Shrink Film, garment bags It iq chemically similar to HDPE, but is less dense and more flexible Most polyethylene film is made from LDPE you often see plastic bags and groceries This drop may be clear or pigmented and is hand sorted and baled for recycling processing plants.
LDPE Recycling is verry similar to HDPE unless special mills are used to manage the thin films The films are often washed and repelletized or used directly to produce new products Some end uses for recycled LDPE are plastic trash bags and grocery bags , plastic tubing, agricultural film and plastic lumber.
PP polypropylene - refrigerated containers, bags, most bottle tops, carpets, some food packaging.
PS Polystyrene - Throwaway utensils, meat packing, protective packaging.
Usually OTHER plastic layers or mixed No recycling potential - must be landfilled.
These symbols are intended to indicate the type of plastic, not its types recyclability 1 and 2 are usually recycled Type 4 is less commonly recycled The other types are generally not recycled, except perhaps in small common PC test programs polycarbonate plastic and acrylonitrile-butadiene-styrene ABS styrene have no recycling figures chemical engineers say there are many more types and uses for polymers But most debates in the recycling concentrates these seven categories.
plastic consumer goods not identified by code numbers are not collected plastic sheeting, pipes, toys, computer keyboards, and many other products do not simply correspond to the numbering system which identifies the plastics used in consumer containers There are actually thousands of different varieties of plastic resins or mixtures these resins are developed to meet the needs of particular products There are limited recycling some products in specific plastic truckload quantities from industrial sources is entered into the collection business a variety of these plastics in small quantities.
When the glass, paper and cans are recycled, they become similar products that can be recycled and used again and again with the recycling of plastics, however, there is generally only one reuse Most bottles pitchers don t become containers of food and drink again, for example, soft drink bottles could become carpets or stuffing for milk jugs sleeping bags are often processed plastic timber, recycling bins, and toys.
A recent development has been the recycling of soft drink bottles bottles bottles regenerated Although it is technically possible to make a 100 recycled bottle, there are serious economic issues as some critics claim that the environmental impact of the process regeneration is quite high in terms of energy use and hazardous by-products.
Currently, only about 3 5 all generated plastic is recycled compared to 34 of the paper 22 of glass and 30 metals At this time, the recycling of plastics only minimizes the amount of virgin resources used to manufacture articles plastic recycling, glass and metal, materials which are easily recycled more than once, saves much more energy and resources are saved with the recycling of plastics.
Consider this example of polyvinyl chloride PVC bottles are difficult to distinguish from PET bottles, but a bottle of parasite PVC in a bath of 10,000 PET bottles can ruin the entire batch is easy to understand why recycled plastics buyers want to ensure that the plastic is sorted properly equipment to sort plastics is being developed, but currently most recyclers are still sorting plastic by hand, which is costly and time-plastics are also bulky and cumbersome to gather in short, they take a lot of space in recycling trucks.
PVC is used for packaging and other short-life consumer products, furniture and long-term assets, most building materials such as window frames and pipes produced short-lived eliminated few years have caused serious PVC waste problems, especially when incinerated the average life of long-life products is about 34 years of PVC products and long life products sold since 1960 are now just starting to get into the flow of waste We now see that the first stages of an imminent PVC waste mountain.
There are currently more than 150 million tons of PVC material long in existence worldwide, mainly used in the construction sector, which constitute the waste mountain in the coming decades Given the continued growth of production by the year 2005, this amount will double and the world will face about 300 million tons of PVC from entering the waste stream the amount of PVC waste from countries industrialized is already expected to grow faster than the even more disturbing PVC production is the fact that the PVC industry is expanding rapidly in Latin America and Asia, so that eventually a mountain of waste increasingly be generated in these regions.
In the 1980s the end, PVC recycling was promoted by the vinyl industry to make it more acceptable to the public and PVC to prevent government action to limit the production of PVC and use Accordingly, general public and policy makers now accept recycling as a technical solution to the environmental problems associated with PVC This is particularly the case in countries with advanced recycling policies, such as Denmark, Germany, the Netherlands and independent research USA shows that by the year 2005 it will be possible to mechanically recycled PVC consumed 15 -30, and at a very high cost, it is virtually impossible to separate, collect and recycle 70-85 thus remaining for 70- 85 of PVC wastes, recycling is not even an option for medium and long term a major problem in the recycling of PVC is its high chlorine content of the raw PVC - 56 weight of the polymer - and the high levels of hazardous additives added to the polymer to achieve the quality desired of the additive material may comprise up to 60 s of a weight of PVC plastics material, PVC uses the largest proportion additives.
As a result, PVC requires a separation of other plastics and sorting before PVC recycling Mechanical recycling is particularly problematic because of the high costs of separation and recovery, loss of quality of materials after recycling, low prices recycled PVC market compared with virgin PVC and, consequently, the limited potential of recycled materials in the PVC market of the existing recycling of PVC materials is not feasible at present, economically or environmentally and it is doubtful that it will ever play an important role in the management of PVC waste PVC industry seems to recognize that PVC recycling is no solution for PVC waste and therefore it is not surprising that industry is now lobbying for PVC incineration as an option for energy recovery, hydrochloric acid or salt in Europe o ccidentale and Japan and landfill in the United States and Australia that local authorities strength to shoulder the burden of pollution and costs of PVC consumption.
Incineration is not a viable option for the treatment of waste less energy is generated from the combustion of the plastic that is used to do, and incineration also means that the carbon it contains is issued as CO2 - a greenhouse gas toxic substances are emitted, and large amounts of solid waste are produced as slag, ash, filter residues and neutralizing salt residue part of this need be disposed of as hazardous waste.
Despite these concerns, PVC production continues to increase, particularly in developing economies where PVC waste is encouraged PVC consumption is exported from the United States, Europe and Australia developing countries often for recycling in inferior products such as shoes and low quality pipes or downcycling According to the Minister of Environment of Indonesia, up to 40 plastic waste imported into Indonesia is not recycled but disposed of directly, partly as downcycled hazardous waste will eventually be discarded or burned since downcycling simply delays the inevitable need for PVC plastic waste given the large volume of long-term PVC products due to become waste in the coming decades, and the expected increase in PVC production, it becomes apparent that PVC Internatio final elimination is urgent only that stop growing, the problem of dangerous and intractable waste.
policy frameworks for PVC phaseout already exist The Conference North Sea Ministers decided in 1995 to stop the environmental emissions of hazardous substances within one generation According to the Swedish Chemicals Committee, PVC has no place in a society sustainable and should be phased for all uses by the year 2007, Denmark proposed restrictions on the use of softeners, lead and other additives used in PVC plastic and undermine the potential for recycling claimed by the PVC industry in the Czech Republic decided production disposal, import and use of PVC packaging from 2001 and Switzerland has banned PVC bottles of alcohol in 1991.
In Europe and Japan, there are few sites left that can be used for landfilling Since the main mass of household waste consists of plastic there is much interest in the recycling of plastics and production plastics which can be removed safely and easily in the environment.
One option is to produce polymers that are truly biodegradable and can be used in the same applications as polymers existing requirements for such materials is that they can be treated through the molten state, they are waterproof water, and maintain their integrity during normal use, but are easily degraded in a biologically rich environment.
Polyhydroxyalkonates are a family of natural polyesters produced as carbon storage granules by many bacteria Zeneca Bioproducts currently producing these polymers to scale pilot plant under the trade name BIOPOL TM Bristol polymer group has been actively involved in the development of these polymers, particularly in the determination of optimum processing conditions.
Strong shear state Pulverization A new technology for the recycling of plastics and production of powder Polymer Technology Center PTC, Department of Chemical Engineering, University Northwest, a revolutionary proprietary technology for the recycling of plastics has been developed that eliminates sorting by type or color This technology, called Solid State shear Sprayer S 3 P is a one-step process in continuous for the recycling of pre unsorted or post-consumer plastic waste Unlike conventional recycling, S 3 P product uniform powders that can be used to manufacture a variety of high quality products.
S 3 P subjected high shear polymers and high pressure while rapidly removing heat from the process friction to prevent the melt S 3 P can convert multicolor waste, mixed, sorted, industrial plastic waste and virgin resins a uniform, light-colored powder partially controlled granulometry reagent and particle size distribution These powders are suitable for the direct smelting conversion by all existing plastic processing techniques This saving process energy sprayed in sizes of powders particles from coarse 2000microns 10 mesh fine 635 mesh 20 microns the resulting powder can be used in a variety of consumer goods and special products for non-food applications are seen throughout the industry in all of auto parts and appliances to office equipment and has meublement samples made from either single polymers or mixtures thereof mixed with the S 3 P process often show improved mechanical properties, such as elongation, tensile strength and the strength flexura compared to samples which do has not undergone the S3P process.
A full recycling operation of mass consumption of electrical and electronic products should be based on the large scale removal process in order to reuse the polymer materials for high-end products and to minimize the amount of chemical waste the identification and analysis of polymer additives are required economic aspects require fast response time 1 s, the handling and easy integration into automated or at least semi-automatic according to the macroscopic physical methods, example on the basis of density measurements are not sufficient to separate polymers, the identification must use the methods of monitoring or molecular structural properties of the plastic in the study.
The close near infrared spectral range infrared is used to control or molecular structural properties of the plastics material under study at the Fraunhofer Institute for Chemical Technology ICT applying NIR near-infrared spectroscopy for the identification of polymers was studied extensively the spectrometer system presented is based on the optical fiber for absorption and reflection measurements, an AOTF of acousto-optic tunable filter and a transputer system is capable of detecting spectra 1000 and identify 20 parts s.
In the near infrared NIR spectral range of 700-2500 nm molecules absorb light by harmonic or combined vibration Recording spectra bulky samples which are of practical interest in recycling processes is CH possible, OH, NH and CO groups observed in the NIR spectra are polymer characteristics and allow identification of the most commonly used ICT an AOTF-NIR fast scanning spectrometer materials was developed spectrometer scanning speed for this purpose can reach 1000 ms nm with a time delay of 0 01 ms between two spectral scans over 100 spectra can be stored at lower wavelength resolution scanning speeds reached 2 to 3 nm for the identification of two systems have been developed, used for identification of technical plastics in consumer products if tools, electron products ic, etc. and plastics in bottles of household waste, mugs etc. Two detector heads have been developed a detection head has a fixed measuring plane and can be operated manually or automatically the second detection head has a larger measuring plane and allows simultaneous observation of the reflected and transmitted light sample moving.
Polymer samples differ in structural composition of aromatic or aliphatic groups, as can be seen from the spectra of plastics materials, in particular when applied in consumer products contain fillers, plasticizers, colorants and additives These components, as well as treatment and surface treatment strongly influence the spectra obtained from plastics materials, in particular carbon black absorbs all light and even small amounts 0 1 reduce reflection of NIR light or transmission to levels that are not sufficient for identification Nevertheless identification of non-black polymer is almost always possible parameters for identification.
The identification of plastics requires the wavelength range of 1000-1800 nm, if the plastics are of a similar type of material, such as references, e.g., plastics of household waste or glass fibers reinforced cases and parts of electronics therefore, in this application, a non-cooled Ge detector can be used.
In the case of household waste mainly PE, PP, PET, PS and PVC are of interest, and the range could be reduced to 1600 to 1800 nm in the ABS electronics, PA, PP, PBT, PC and PMMA are found in greater amounts NH PA groups require a line extension to less than 1 400 nm.
Household waste is showing spectra of sufficient quality so that the range of 1600 and 1800 nm can be scanned in 1 ms or less material glass fiber reinforced technical products require more analysis time or the average of spectra .
A study of undyed black samples of real statistical uncleaned plastic waste showed that more than 95 samples were identified labels, dyes and the inscriptions on the household waste not to disturb the identification of significantly misidentifications was below 0 1.
B infrared spectroscopic Focal Plan matrix FPA - Applied Spectroscopy in June 1997, a near-infrared spectroscopic imaging system, using a network of FPA detector focal plane, is presented for measurements remotely and online at the macroscopic scale online spectroscopic imaging requires high-speed sensors and short image processing steps therefore the use of a focal plane array detector in combination with chemometric software is fast identified as these new spectroscopic imaging systems generate so much data, it requires multivariate statistical techniques to extract important information from the multidimensional image pectroscopic these techniques include principal components analysis and PCA and linear discriminant analysis LDA for supervised classification spectroscopic image data clustering is a spot tedious in spectroscopic imaging, but a procedure is presented to facilitate this task and provide a better overview and control of the composition of data sets The identification system is built, implemented and tested in a real application identification of plastic in municipal solid waste.
While plastic former can be upgraded by melting and reforming into new uses, while volumes become larger, it becomes increasingly difficult to find opportunities enough The solution is to break the plastic down, extract the valuable portion of hydrocarbons and using it to make fresh plastics and other valuable raw materials.
BP Chemicals Grangemouth a leading technology in this field he calls Cracking This polymer has reached the stage of development of metal platform at a rate of 1 kg h h with a unit 20 kg for large tests scale up currently serving This will be followed by a unit of 100 kg hr with all the design features considered.
The plant is controlled by means of an integrated database in real time RTD system developed by BP Chemicals themselves.
The requirement was a sophisticated and flexible display system that could be easily augmented intelligent rules to help in controlling the process, it is important that the solution could be easily integrated into RTD.
As in any research and development environment, the plant can change several times during his life, and this requires flexibility in operator interface It is important that the system could be developed and maintained by technicians such as development chemists.
The requirement rules or intelligence arises from the need to design a commercial facility that is robust and easy to use so that the plant can be operated by unskilled personnel of full-scale plant will be located in the production of polymer petrochemical Refining and recycling complexes in most cases, particularly complex recycling, in-depth knowledge of the process is unlikely to be available on request This could have consequences in terms of overall operation of the plant, as in terms of maintaining the efficiency and product quality, but perhaps even more important in terms of diagnosing and correcting problems.
In the United States 75 billion pounds of plastic are produced each year, unfortunately, the majority of this plastic ends up in Where plastic discharges are dumped in landfill decomposition process can take 10 to 30 years recycling has become a reasonable solution to the landfill problem.
There are five factors that are necessary for plastic recycling to be a first successful process, the supply of plastic used to be a large amount this large amount of plastic is collected in some areas, which the second stage when the plastics material is collected, sorting and separation process begins; This is the third step in the process of sorting and separation processes depend on the type of polymers that make up the plastic plastic products are codes given to assist in sorting and separating the fourth step into the plastic recycling is the polymer reprocessing reprocessing includes the melting process, the melting process can be accomplished if the polymers have not been widely crosslinked with synthetic fibers If the crosslinking of polymers contain too many synthetic fibers, the polymers will be difficult to stretch and less flexible the final step in manufacturing the molten plastic material in new products.
Codes on recyclable plastic containers are helping the most in the sorting and separation process of the six classes of plastics are separated into two polyethelyne zones plastics and polymer plastics Plastics are labeled polyethelyne HDPE, for high density polyethelyne; or LDPE, low density polyethelyne The four plastic polymers which are recycled include polyvinyl chloride, labeled V; polystyrene, labeled PS; polypropylene, labeled PP; and polyethylene terephthalate, labeled PETE These names and labels can seem confusing, but they are a necessity in the process of recycling.
There are four types of recycling processes occurring usually primary, secondary, tertiary and quaternary Primary recycling process is the recycling of materials and products that contain similar features to the original product This process is only feasible with materials plastic semi-clean industrial waste, therefore, this process has not been widely used secondary recycling allows a higher blend levels in combination plastics When the secondary recycling process is used, it creates products such as fence posts and derivatives that can be used in the substitution of wood, concrete and metal poor mechanical properties of these types of plastics are the reason why the above products originate tertiary recycling occurs more and more today because of the need to adap ter the high levels of contamination of waste the actual process involves the production of basic chemicals and plastic fuel the latest form of recycling is the process This process uses quaternary quaternary energy fro m plastic from burning This process is the most common and widely used in recycling the reason why this process is widely used is due to the high content of heat most plastics most incinerators used in the process can reach temperatures as high as 900 to 1000 degrees Celsius for new techniques by the concern for the environment used with incinerators have decreased the amount of pollutants being released.
The incineration use in the quaternary process is most advantageous because the high temperature of wastes heating process is reduced 80 to 90 weight and bulk materials left on the form of this process are then placed in landfills.
A current promotion program sponsored by the plastics industry emphasizes the positive contributions that plastics are and claims listed in these ads are accurate.
But as noted in the article on the previous page, the largest single use for plastics is the packaging because the packaging has a short life, he made much of the flow of plastic waste but where it leads waste streams.
In general, the Agency for Environmental Protection said that in the early 1990s, about 80 percent of all municipal solid waste sent to landfill, 10 per cent was incinerated and 10 percent were While recycled more recycled plastic, said the EPA that plastics make up about 20 percent of solid waste is landfilled.
Most consumers believe that the slow degradation of plastics is the main reason that plastics should be recycled However, research has shown that other waste, such as paper, wood and food waste, degrade very slowly in landfills.
The most serious problem with waste plastics regards additives in plastics These additives include colorants, stabilizers and plasticizers which may include toxic components such as lead studies and cadmium indicate that plastics contribute 28 percent all of cadmium in municipal solid waste and about 2 percent of all principal investigators do not know if these and other plastic additives contribute significantly to products leached from municipal landfills.
How toxic are plastics that are burned Researchers know that don t or plastics containing heavy metal-based additives can also contribute to the metal content of incinerator ash EPA is looking for substitutes cadmium based additives of lead and.
Another concern is the use of petroleum products All plastics began their life like oil by increasing the recycling of plastics, scientists and engineers are able to reduce the dependence on oil.
Before plastic waste can be converted into new products, different types of plastics are to be separated initially plastic recovery companies relied on manual sorting or by consumers themselves or by paid workers but manual sorting is considered as too unreliable and too expensive.
At least two organizations have developed plastic automated sorting systems National Recovery Technologies received the EPA of the year small business National Award in 1991 for his efforts in the development and commercialization of a broadband system automated which effectively separates vinyl those marked containers 3 of mixtures of whole plastic containers or crushed post consumer NRT said that the presence of chlorine atoms within vinyl resins triggers a timed air burst computer separating the vinyl plastic containers of the mixed stream the company has also developed a system that optically scans mixed plastics to separate PET soda bottles HDPE milk jugs, light green PET PET, as well as other specifications .
Sandia National Laboratories, working with the US Department of Energy, designed a device to classify plastic waste in one of seven categories of plastic near-infrared light is used to distinguish plastic from another by using the characteristics vibration-specific Sandia engineers report that the device can classify many types of plastics with a success rate of 98 to 100 percent the laboratory has issued a license for the commercial development of this new device.
Carters old recycled phone ABS innovative mounting panels.
Finding new uses for recycled plastic from old phones, AT T Bell Laboratories engineers are remolding phone housings discarded mounting panels for AT T business telephone systems and improving service to business customers.
Until now, when a phone has reached the end of his life, AT T would sell the plastic to a recycler who grind and sell it on the secondary market, where it has been transformed into products ranging from cassette park benches, said Werner Glantschnig, member of the technical staff of Bell Laboratories and the head of the project.
However, we wanted to see if we could close the loop and we reuse the millions of pounds of ABS plastic flakes in a way that makes sense to both the environment and business.
ABS or acrylonitrile-butadiene-styrene plastic flakes can be converted to t new phones because the colors change during reflow, and the plastic loses the smooth finish and gloss AT T needs for its phone cases.
When we shape the ABS mounting panels telephone system, color disperse well in a gray uniform and the finished product meets all our needs, said Louis D Anjou, another Bell Labs engineer and designer panel.
With these ABS panels, in the T of supply centers can now assemble and test the business phone systems before delivery in local Previously the customer, these panels had to be custom made of plywood and against the assembled system tested at the customer location in addition to reducing the use of wood, the new method is much more efficient, reducing the time and cost of installation.
AT T engineers and designers are looking for alternative uses for ABS plastic flakes, including coils optic telephone cables and copper fibers.
This is encouraging that awareness of the environment and the concept of design for environment spread through the AT design community T said John C. Borum, AT T and environmental engineering vice president security Our aim is to remain at the forefront of companies that respect the environment by recycling as many of our products we can .
Throughout the environmental movement, the researchers are concerned with products that are discarded in large quantities of junk cars are one of these products, but the junk cars pose particular problems due to the combination of products used in automotive junk cars Used metals have long been recycled, and now many researchers are turning their attention to other automotive components.
The Center of Excellence in polymer science and engineering at the Illinois Institute of Technology focused project on 400 million pounds of polyurethane foam discarded each year from junk cars ITI patented a pure extrusion process in the solid state and a device that could be used to recycle the waste, along with a wide range of other waste polymers and rubbers.
The IIT system, known under the acronym RCSS, sprayed with a polymer material, the production of fine powders, which have many applications for industry The advantage of HSSE is that it can be economically applied to many types of waste natural and synthetic polymers the Center of excellence in polymer science and engineering notes that many recycling process developed to date have been limited to certain types of waste most processes have not been economic, especially in the amount of energy needed, they add, and recycled materials are not produced in forms that are needed and used for remanufacturing.
The RCSS technology was optioned to a New York company for possible development More information is available from the Public Relations Office of the IIT, 312 567-3104, or on the website of the IIT.
Research on recycling of chemicals may open new opportunities.
The US Department of Energy conducts ongoing research on the recycling of plastics This report highlights new approaches to chemical recycling Plastics recycling can be expensive and difficult because of the constraints on the contamination of waste and inadequate separation before recycling chemical recycling could remove some of the restrictions.
Pyrolysis and hydrolysis are two processes which have proved promising in the recovery of commodity chemicals and fuels from waste plastic pyrolysis is a method in which the plastic waste is heated in the absence of oxygen a closed chamber, the pyrolysis products can be used as a chemical feed or fuel load hydrolysis decomposes the waste plastics through a series of chemical reactions.
Research sponsored by the US Department of Energy Office of Industrial Technologies at the National Renewable Energy Laboratory has led to the development of a new process based on the pyrolysis of certain waste streams This process recovers monomers , the basic elements of a polymer, and high value chemicals that are sufficiently pure to be used in the manufacture of new plastic the advantage of this method is that the waste plastics are not to be separated in advance this eliminates labor stage in the current process it will also reduce the cost of the monomers and chemicals and will reduce oil consumption, the source of chemical raw materials used to produce plastics .
In the novel process, the monomers and of high value chemicals are recovered from the manufacture or sequentially pyrolysis post-consumer waste The reaction products are subjected to detailed chemical analysis to determine the conditions which allow control pyrolysis reactions this allows the design of a process to recover the desired product with high yields, reducing the subsequent separation and purification requirements of the target product NREL has filed patent applications to cover the process for a total seven streams of mixed plastic waste.
For example, NREL demonstrated the new carpet recycling method discarded caprolactam, the monomer of nylon 6 value used in about half of the carpet fibers, can be isolated in yields of 85 percent This can be done without separating the nylon of the support material.
An economic evaluation of caprolactam recycling carried out by an economic independent firm shows promising applications Results of the project a commercial scale plant recycling 100 million pounds of carpet waste could produce high quality caprolactam to about 15-50 cents per pound the chemical is currently selling 90 cent to 1 per pound in other words, caprolactam recycling could reduce its costs by 50 percent or more.
Other applications of the chemical recycling process include the recovery of terephthalic acid from polyethylene terephthalate or PET, in mixed plastic bottles and recovering styrene from recycling of PET mixed residential plastics has not economic favorable than the application of polyurethane due to the lower value of the plastic bottles, but the potential volume of the waste stream is very large researchers estimate that 900 million thermoplastic polyester resin of books, PET is a major component, could be recycled each year.
Researchers are developing the technology base for the chemical recycling process and identify promising new applications for specific waste streams experiments are currently underway using engineering scale reactors to confirm processes and reactions to refine the operating conditions.
Here's a simple activity to share with students to help them understand certain characteristics of plastics and other polymers has been developed for the National Science Laboratory, Sandia and Math Carnival This activity is offered for students in third through eighth grade.
Gluep is a polymer based on sodium tetraborate and borax white glue Each of these materials is already adhesive polymer is a mixture of forms of polyvinyl acetate and polyvinyl alcohol borate Borax long chains in a solution When the two aqueous materials are mixed together and the mixture was kneaded by hand, crosslinking of polymer chains occurs due to a hydrogen bond with the water molecules connecting the two polymer chains the physical properties of the mixture are quite different from the individual properties of the compounds, the resulting Gluep is a semi-solid plastic material -As.
4 percent solution of borax 1 4 cup borax dissolved in 1 liter of water of white glue mixture valve 50 50 mixture of glue and water, and the mixed food coloring plastic Ziploc bags.
1 Pour 15 ml 1 tablespoon of the borax solution in the bag 2 Add three drops of food coloring 3 Add 60 ml 4 tablespoons of white glue mixture 4 Zip the sealed plastic bag 5 knead thoroughly until the color is uniform and the water is no longer visible consistency must be reached within 10 minutes Gluep 6 Remove the bag by rotating the inner bag and the friction of the sides 7 of Gluep Gluep store in the plastic bag .
How Gluep as solid as a liquid What happens if you leave the bag Gluep What happens if you freeze it.
Try other experiments with Gluep What happens when the additional solution of borax is added What happens when the additional adhesive is added What happens if a base or an acid is added during the After the mixture has hardened Gluep.
For a complete lesson plan for this event, visit the Sandia web site.
The bottle PET bottle consumers know that one soda bottles was patented in 1973 by chemist Nathaniel Wyeth, brother of American painter Andrew Wyeth distinguished.
The average household generates about 17 pounds of PET bottles used annually is equal to the amount of aluminum used.
Eight two-liter bottles is equivalent to about a PET book.
When PET bottles are crushed and tied into bales of 48 inches, a ball can hold about 4,800 bottles and weighs about 1,200 pounds.
Five PET bottles provide enough fiber for one extra large T-shirt or a carpet square foot Half of polyester carpet made in the United States is made from recycled plastic bottles.
Twenty-five two-liter bottles can make one sweater.
Five two-liter PET bottles produce enough cotton for a ski jacket.
It takes 35 PET bottles of two liters to make enough fiberfill for sleeping bags.
wood substitutes such as green plastic park benches base cups for soda bottles pipes Toys flowerpots, buckets and drums barrier traffic cones bins.
The recycled American Plastics Council reports that consumers almost half of all PET soda bottles produced in 1994. About a quarter of milk jugs were recycled.
No one can predict what the next generation of research and engineering recycling bring very young engineers young engineers are already considering the question if the report of the Eighth grader Nick Gidzak polar Bay, Manitoba, Canada, is any indication, the sky's the limit.
plastics recycling and mix it with cement to make bricks.
This year, I entered my beautiful school science and earned a silver medal for this project, I went to the science fair division and earned a gold medal and engineering award when I went to the Manitoba schools science Symposium, I received a project excellence award by the professional engineering Society of Manitoba.
For my project, I cut plastic milk cartons and plastic containers of soft drink two liters and mix it with cement to make bricks I made three bricks with different amounts of plastic mixed with cement the first brick was made with more plastic was the second half as the last brick was no plastic.
After the bricks, I left out for four months, it snowed, rained and was sunny After four months, I brought them inside and then I pumped water on the bricks for two weeks, the water passed bricks and show how the effect of erosion he made the results showed that the brick with the most plastic blended showed less erosion.
A legislative objective of the European Union to recycle a minimum of 15 percent of plastic packaging waste in 2001, is close to being achieved, judging by the latest annual figures published by the Association of Plastics Manufacturers Europe APME.
The plastic packaging recycling rates in the EU European Union has grown from 14 percent in 1995 to 14 7 percent in 1996, proportion of total plastics packaging waste, while proportion of waste incinerated - with energy recovery - increased from 18 to 16 percent the total amount of plastic packaging waste generated in Europe has increased over this period.
Under a European directive of 1994 on packaging, Member States are required to recover at least 50 percent and recycle at least 25 percent of all packaging waste by mid-2001, a minimum of recycling 15 percent for each packaging material must also be achieved.
EU Member States have already begun to consider the next round of targets under the Directive, although the European Commission should not submit proposals by the end of the year According to industry sources, some Member States have already indicated that they want the high target to a minimum recycling rate of 25 percent for each packaging material other governments said they were opposed to setting new goals as data recovery and recycling of packaging waste is improved.
A prominent spokesman for the packaging industry last month called on governments to postpone discussionof post-2000 targets under the Packaging Directive until better data is available Julian Carroll, director of the 'packaging organization based in Brussels, Europen, said the packaging Directive was in danger of failing because of a lack of understanding of the industry.
The counts of APME also show that plastic waste in total rose 5 percent of 16 05 million tonnes in 1995 to 16 87 million tonnes in 1996 While the material recycling rate increased for the third consecutive year 8 to 9 percent, the proportion incinerated with energy recovery decreased slightly from 17 to 15 percent, the overall recovery rate has dropped from 26 to 24 5 percent in Austria posted the highest rate mechanical recycling 20 percent, followed by Germany 15 percent.
recycling raw material plastic, where the materials are chemically and thermally decompose into their constituent molecules and reprocessed, increased by 150 percent from 99,000 tons to 251,000 tons.
Recycling a Japanese car 3, recycling, sorting process for separating bags groceries.