Materials Crisis

Even with energy expenditures stringently controlled, or an abundant clean source of energy developed, the prospects of achieving sustainability in the long term is seriously threatened by the rapid depletion of essential material and mineral resources. The manufacturing of goods invariably involve using concentrated pools of naturally occurring raw material resources leading to their eventual dissipation in the environment. For instance, the manufacture of plastics uses up a fraction of the...

Stabilization Of Plastics

Polymeric films used in greenhouse and mulch film applications have been a subject of great interest to additive manufacturers, film processors, and researchers for over 25 years 29-34 . In the 1960s and 1970s antioxidants and UV absorbers provided basic levels of protection against thermal and UV degradation. During the 1980s, hindered amine light stabilizers (HALS) extended the service lifetime of a range of polyolefin-based applications. Even during the past 10 years development has...

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AI Fe PETPVC PS PP PE AI Fe PET PVC PS PP PE Al, Fe life cycle inventories for packagings. Environmental series no. 250 I. Swiss agency for the environment, forset and landscape. Berne, 1998 Plastics actual data sets of APME (http lca.apme.org. date 31.05.2000) AI Fe PETPVC PS PP PE AI Fe PET PVC PS PP PE Al, Fe life cycle inventories for packagings. Environmental series no. 250 I. Swiss agency for the environment, forset and landscape. Berne, 1998 Plastics actual data sets of APME (http...

Recycling

When packages and package systems are being designed or modified, relatively small changes can sometimes make the difference in whether the package will be recyclable at the end of its life or whether it will not. (It should be noted that the term recyclable means different things to different people it is used here in its practical sense, of being capable of fitting into existing or developing recycling programs and, hence, likely to be recycled at the end of its useful life.) First, in the...

Magnitude Of The General Incineration Problem

The United States generates about 1.8 kg (approx. 4.0 lb) per person per day of solid waste see Chopra et al. 1 . This translates to over one billion tons of municipal solid waste generated annually. In addition to this, the United States also generates about 300 million metric tons (where 1 ton is 1000 kg) of hazardous wastes, and over the past one or two decades it has been growing at a rate of about 5-10 annually. Oppelt 2 reviews the information. Medical waste (heating value approx. 14 MJ...

Types Of Plastics Packaging

Plastics packaging can be grouped into the general categories of rigid and semirigid containers, flexible packaging, and other forms. In the container category, bottles are the most common package type, but plastics are also widely used in tubs, tubes, drums, bins, trays, and other shapes. The flexible packaging category includes wraps, pouches, bags, sacks, envelopes, and similar packages. The other category includes, among others, cushioning (loose-fill and molded), blisters, caps, and lids....

Info

APackage A Hostavin N30 + Hostavin AR08. bPackage B Tinvin 622 (HALS 5) + Chinassorb 944 (HALS 6). The effect of soaking time in pesticide use is measured using a UV spectrometer. Table 5.7 shows the effect of pesticide and irradiation on the ultimate elongation of PE films. This study showed that a large number of pesticides do not interact with the stabilizer package. Some sulfur-containing compounds and organic halogenides initiate oxidation of PE and lead to faster deterioration of...

Laboratoryaccelerated Weathering Tests

Laboratory-accelerated test devices that utilize artificial light sources have been used for more than 80 years to support the development of progressively more weatherable formulations as well as for quality control and specification tests. The devices allow control of the three main test parameters, that is, radiation, heat, and moisture, for more consistent exposure conditions compared with their variability outdoors. The consistency of exposure conditions is often monitored with a...

Depletion of Non Renewable Fossil Fuels and Raw Material Reserves in Production of Plastics

The plastics industry, in common with other industries, utilizes fossil fuel energy and raw-material resources for its operation. The question to consider is if the magnitude of the drain on energy and raw materials by the plastics industry is justified by the benefits plastics offer society. This is essentially a value judgment that involves assessing the marginal utility derived from the use of plastic products (as opposed to substitute products) by the society at large. As shown in Figure...

Yarn Preparation

After formation, yarns must be prepared for fabric formation. In the case of knitting yarns, this involves clearing the major defects, lubricating the yarns with winding emulsion or mineral oil, and winding the yarns onto cones for the knitting creel. Any lubricants, tints, or other chemical processing assistants added at this stage eventually become wastewater pollution during subsequent knit fabric preparation processes. Weaving yarns, on the other hand, must be sized using a chemical mixture...

References

Further information may be obtained from Association of Plastics Manufacturers Europe, (APME), Brussels, or on the Internet at http lca.apme.org reports htm 14.htm. 2. Einflu des Einsatzes von Kunststoffen auf den Energiebedarf und die energiebedingten CO2 Emissionen im Bereich der W rmed mmung, Fraunhofer Institut fur Systemtechnik und Innovationsforschung, Karlsruhe June 1999 or on the internet at 3. M. Heyde and T. Nuerrenbach, Use of Plastics in the Car Manufacturing Industry, Fraunhofer...

Basic Plastics Recycling Definitions And Nomenclature 565

Is significantly greater than that of wood or coal. Many plastics can also be thermally or chemically depolymerized into monomer(s), petrochemical feedstocks, and fuels. The end result is that several forms of plastics recycling can be defined. D5033-00 describes the following Primary recycling is the processing of scrap plastic product into a product with characteristics similar to those of the original product. Secondary recycling is the processing of scrap plastic into a product that has...

Use of Ozone Depleting Substances by Plastics Industry

Both ground-based and satellite measurements have unambiguously established that the stratospheric ozone concentrations have been slowly falling since the mid-1980s (see Appendix B for a discussion of Stratospheric Ozone Depletion). The ozone concentrations in the stratosphere are latitude dependent and the decline in concentrations is uneven. The Antarctic winter ozone hole (with about a 50 loss in ozone within it) in the 1990s is an extreme case of the depletion exacerbated by the polar...

Preamble

Experimental and theoretical studies are presented from a laboratory-scale thermal destruction facility on the destructive behavior of surrogate plastic and nonplastic solid wastes. The nonplastic waste was cellulosic while the plastic waste contained compounds such as polyethylene, polyvinyl chloride, polystyrene, polypropylene, nylon, rubber, and polyurethane or any of their desired mixtures. A series of combustion tests was performed with samples containing varying composition of plastic and...

Some Results

The results obtained on these three samples from TGA and DSC are shown in Figures 15.25-15.36. They show the mass left and heat flow into or out from the sample as a function of temperature. The TGA results on cellulose show the presence of combined moisture in the sample under both inert and oxidative Temperature ( C) Figure 15.25. Thermal decomposition of cellulose in nitrogen. Temperature ( C) Figure 15.25. Thermal decomposition of cellulose in nitrogen. Figure 15.26. Thermal decomposition...

Conversion to Waterborne and High Solids Coatings

A switch from solvent-borne to waterborne systems is one of the most frequent responses to government regulation of solvent emissions. One of the reasons that this switch has not gone even farther is that the strategies for making hydrophobic paint films from water systems are only partially successful. Films are often not hydrophobic enough for many demanding end uses. Architectural paints, however, are mainly waterborne, as shown in Table 6.5. Waterborne systems represent 69.0 of the exterior...

Plastics as a Reductant and Fuel for Steel Blast Furnaces

Recovered plastics from packaging and from end-of-life durable goods have been evaluated as a replacement for coke in steel mill blast furnaces 131 . Coke serves as both a reductant and fuel according to the following basic blast furnace chemistry Fe2 3 + 3CO 2Fe + 3CO2 Fe2Os + 3H2 2Fe + 3H2O Figure 14.27 shows a schematic of a steel mill blast furnace. Plastics, like coke, oil, and coal, can be an effective source of carbon and hydrogen, and their use in the steel-making process is an...

Wool Finishing

Four high-priority areas were identified by a study group of the International Wool Secretariat (IWS) (49-51). They were pesticide residues in wastewater from wool from pesticides applied to sheep, discharge of mothproofing agents from wool carpet manufacture, halo-organics from wool shrink proofing, and chromium from chrome dyeing. These are being regulated and the aquatic toxicity from wool operations due to these types of materials must be reduced 49, 73, 74 . Also, as previously mentioned,...

Co2h

Hydrolysis of carboxylated poly(vinyl alcohol) derivatives. et al. 75 . The current polymers have little biodegradability at preferred performance molecular weights, ca. 5000 Dal for polyacrylic acid and 70,000 Dal for copolyacrylic-maleic acids. This, even though there are data to indicate no harmful environmental effects, has resulted in a massive search for biodegradable replacements. The value of negative results mentioned earlier is strongly reflected here. Many efforts to...

Gross And Net Calorific Values

One aspect of energy calculations that causes many problems in interpretation is the conversion factor used to convert fuel mass to energy. The conversion factor is called the calorific value of the fuel and represents the quantity of energy that can be derived from unit mass of fuel. There are, however, two types of calorific value gross and net. Gross calorific value is the energy obtained from a fuel when the combustion products are returned to the thermodynamic standard state and any water...

Major Appliances White Goods

Major appliances, often referred to as white goods, consist of refrigerators, stoves, dishwashers, washing machines, clothes dryers, air conditioners, microwave ovens, and hot water heaters. Older white goods available for recycling contain large quantities of metal and can be profitably recycled by scrap metal processors using the existing metal recycling infrastructure. The normal procedure is to co-process major appliances with automobiles at automobile shredders. The plastics in white goods...

Color Sorting

The ability to sort plastics by color has been an important component of HDPE and PET bottle sorting technology in order to produce final recyclates of highest value 56-58 . Many bottle sorting lines offer the capability to separate bottles by color as well as by type of resin. In bottle recycling operations, high throughput flake particle color sorters have also been used to accomplish a final polishing step, for example, the removal of traces of colored HDPE flake from a primary stream of...

H

Heat of decomposition of the polymer (kJ g) Heat of gasification of the polymer (kJ g) AHt Net heat of complete combustion (kJ g) AHv Heat of vaporization of the polymer (kJ g) L Optical pathlength through smoke (m) m Generation rate of polymer vapors (g m2 s) M Molecular weight of the monomer (g mol) q> External heat flux per unit surface area of the polymer (kW m2) qcr Critical heat flux per unit surface area of the polymer (kW m2) qf Flame heat flux per unit surface area of the polymer (kW...

Introduction

Marine debris is generally defined as any manufactured or processed solid waste material (typically inert) that enters the marine environment from any source. Marine litter andfloatables are considered equivalent terms 1 . Marine pollution is defined as the introduction by man, directly or indirectly, of substances into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hindrance to marine activities including fishing, impairment of...

Combustion Of Polymer Vapors

Combustion is a process where polymer vapors react chemically with oxygen from air in the reaction zone of the flame, generating heat and products of complete and incomplete combustion. The fire intensity and thermal and nonthermal hazards in fires depend on the release rates of polymer vapors, Table 11.8 ASTM Small-Scale Test Apparatuses for the Measurements of Release Rates of Heat and Fire Products and Light Obscuration by Smoke Table 11.8 ASTM Small-Scale Test Apparatuses for the...

Starch

Starch is a carbohydrate that is synthesized in the organs of plants as a reserve food supply for periods of dormancy, germination, and growth 25 . Starch is the second most abundant renewable substance, after cellulose. Starch can be considered a condensation polymer of glucose consisting of two types, amylose, a linear-chain molecule of a-l,4-linked D-glucose, and amylopectin a branched polymer of a-1,4-linked D-glucose with a 1,6-linked D-glucose branched. Due to its function as a food...

Mulch Films

Polyethylene plastic film was first used as mulch in the late 1950s. It helps to accelerate plant growth by increasing soil temperature and stabilizing soil moisture. When scheduled drip (or trickle) irrigation is used, plastic mulch helps maintain optimum soil moisture, aids plant establishment, and promotes excellent crop growth throughout the season 47 . The vegetables on plastic mulch routinely mature 1 -2 weeks earlier than those on bare ground. Plastic mulch also helps protect vegetables...

Plastics Used on the Exterior of Vehicle

Polymers are used in many areas on the exterior of the vehicle. These include a variety of components such as moldings, trim, appliques, body panels, doors and exterior mirror housings, front and rear fascia, and lighting systems and pickup beds. Door seals can be made from thermoplastic elastomers. These materials must meet performance, durability, weatherability, and styling criteria. Moldings and Trim Exterior plastic moldings are a fairly recent addition to the automobile. The move toward...

Effect Of Government Regulations On The Coatings Industry

Development of HSSB and waterborne coatings was well underway by 1950 and predated solvent regulations in the United States 14 . The first volatile organic compound (VOC) regulation, called Rule 66, was passed by the Los Angeles Air Pollution Control Agency in early 1967. The Clean Air Act of 1970 and the Clean Air Act Amendments of 1977 and 1990 have had a huge impact on the coatings industry 15 . Regulations completely changed the path of development of coating technology in some industries...

Binders And Solvents Used In Modern Coatings

The polymeric part of a paint formula that can be varied and sometimes chemically designed to make the cured paint perform well in a given end use is called the binder or sometimes the vehicle. The binder disperses and encapsulates the pigment in the dried or cured paint film. Adhesion of the binder to the substrate is critical throughout the useful lifetime of the coated article. Drying oil and alkyd-based paints served the coatings industry well for many years, but the need for improvements...

Aromatic Polyamides Polyaramids

Aromatic polyamides are more susceptible to the effects of sunlight than the aliphatic types. Significant yellowing and rapid decrease in molecular weight and in mechanical properties result from exposure of unprotected aromatic polyamides to the environment. Aromatic polyamides are affected by wavelengths well into the visible portion of the spectrum. It has been shown that wavelengths in the 400- to 500-nm region cause an appreciable amount of deterioration 6, 38 . Similar to the aliphatic...

Textile Wet Processing Chemicals

Sources for chemical pollution from textile wet processing includes dyes and pigments, specialty chemical, commodities (including water), and incoming substrates. Typically, the largest pollution source is the incoming substrate. However, there are a considerable number of specialty processing assistants, as well as commodity chemicals that are used to prepare, color, and finish greige fabrics 35 . Specialty chemicals typically are proprietary mixtures of commodity chemicals and surfactants...

Collection Of Plastics For Recycling 1471 Consumer Packaging

In the United States, the collection of plastic postconsumer packaging from households is mostly confined to HDPE and PET bottles 13, 20 . This is reasonable since HDPE and PET bottles make up over 95 of all bottles on the market, and much of the remaining plastics packaging consists of lightweight film and foam items that are difficult to collect, clean, and sort economically 21-23 . Households are often asked to set out HDPE and PET bottles commingled with other recyclables. This is not a...

Polyurethane And Other Polymeric Foams

Polymeric foams as a class of materials is of particular interest in the present discussion not only because they are an important component of the waste stream but also because ozone depleting substances (ODS) such as Freon were once widely used as auxiliary blowing agents in their manufacture. However, in the United States and in western Europe, Freon is no longer used for the purpose and the practice is being phased out in many other parts of the world. The Montreal Protocol (along with its...

Carpet Waste And Composition

During carpet manufacturing, the edges of a tufted carpet need to be trimmed and the face yarns sheared. This waste is approximately 60 edge trim and 40 shear lint. In the Dalton, Georgia, region where there is a high concentration of carpet manufacturing activities, over 20,000 tons of carpet manufacturing waste is generated every year. The carpet waste from the fitting process is concentrated in the automotive and prefabricated housing industries 11, 12 . During the fitting process, the...

Injection Molding

Injection molding is one of the most popular processing operations in the plastics industry. In recent years, more than half the processing machinery manufactured were injection-molding machines. The equipment is basically designed to achieve the melting of the resin, injecting the melt into a cavity mold, packing the material into the mold under high pressure, cooling to obtain solid product, and ejecting the product for subsequent finishing. It is different from extruders in that a mold is...

Regulations of Pigments and Additives

Three of the inorganics on the HAP list are of particular concern in the coatings industry chromium compounds, mercury compounds, and lead compounds. Hexavalent chromium is very effective at passivating metal substrates. It is used in various forms in chemical pretreatments of metal 4(g) and as a corrosion inhibiting pigment 4(h) in primers for metal. The main component in metal pretreatment for auto bodies is zinc phosphate, but the last rinse after phosphate treatment has been chromic acid....

Legislation And Regulation

As mentioned, legislation and regulation have been used in efforts to decrease the environmental impact of products or packages, particularly their impact on disposal systems, by increasing recycling and use of recycled content, as well as providing incentives for source reduction. Plastics packaging is often a target of such regulation. The most prevalent approach, globally, is implementation of the philosophy that the entity making the packaging decision should be held responsible for the...

Biosynthesis

Polyhydroxyalkonoates (Bacterial Polyesters) The family of polyhy-droxyalkanoates are polymers produced as intracellular storage materials in a variety of bacteria grown under physiologically stressed conditions. PolyP -hydroxybutyrate-co-P -hydroxyvalerate (PHBV) is a semicrystalline aliphatic polyester that was initially produced commercially by Imperial Chemical Industries, PLC (London, England, ICI) from the bacteria Alcaligenes eutrophus. The homopolymer of poly-P -hydroxybutyrate is melt...

Environmental Issues Related To The Plastics Industry Global Concerns

Specific environmental issues related to the polymer-related industry have been raised from time to time by the general public as well as the scientific community. More often than not, the quantitative data that supports the concerns and estimates the magnitude of the impacts have not been available. Consumer interest in plastic-related environmental concerns, however, continue to increase. This has unfortunately lead to the inaccurate information and indefensible arguments in the press (and at...

The Energy Crisis

Most human endeavors demand large amounts of energy to be spent in a short time scale (i.e., are energy-intensive). This energy is presently available largely from fossil fuels or from a secondary source derived from them. Since the industrial revolution, we have invented machinery allowing a single person to extract and control far more energy than he or she could individually generate or even consume. (The human body can barely produce about 100 W of energy.) From then on we have been...

Identification of Additives

Several techniques have been developed to rapidly identify additives in plastics as part of an overall plastics recycling operation. Some techniques such as Fourier transform infrared (FTIR) can combine resin identification with information of the presence or absence of additives such as flame retardants or talc fillers 49, 62, 65 . The sliding spark technique developed at the University of Duisburg in Germany can identify a range of heavy metals along with the type of resin 68, 69 . A reliable...

Ps

Plastics resins in packaging in U.S. municipal solid waste stream, 1998 1 . Figure 4.5. Plastics resins in packaging in U.S. municipal solid waste stream, 1998 1 . and or multilayer packages containing two or more different polymers are used. Figure 4.5 shows the proportions of major plastics found in packaging in U.S. municipal solid waste in 1998. In 2000, approximately 15,602 million pounds of virgin high-density polyethylene (HDPE) resin were used in the United States and Canada...

Extrusion Blowing of Film

Extrusion blowing of common plastics such as polyethylenes into film is one of the oldest processing techniques (dating back to the 1930s in the United States). The basic process is simple and is based on a special annular die that is connected to one or more extruders. In the simple case with a single extruder, the molten plastic material is extruded vertically upwards through the die into a thin-walled plastic tube. Blowing air into the tube expands the soft molten polymer, deforming it...

Volatile Organic Compound Regulations

One of the main components of smog is ground-level ozone (O3). Ozone is sometimes categorized as a toxic oxidant. It is an eye irritant and a human health risk at levels sometimes reached in air around U.S. cities. The climate and land formations in and around Los Angeles favor temperature inversions that tend to trap air emissions. Other cities experience high ozone less frequently. Trapped organic compounds are susceptible to photochemical reactions that lead to ozone formation. The...

Basic Plastics Recycling Definitions And Nomenclature

As in any technical field, when communicating about the technology of plastics recycling, it is important to use common terminology and definitions. Early (pre-1970) terminology for commercial, industrial, and postconsumer recycling of materials developed around the needs of the paper and textile (fiber) recycling industries and the metal and glass recycling industries. After the first oil price shock of the 1970s, plastic recycling gained attention, and it soon became apparent that the...

E 10 100e 12 100e

1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 Temperature (K) Figure 15.10. Gas yield from pyrolysis of different surrogate wastes. the initial composition of waste material has a significant effect on the thermal destruction process. The removal of some constituents from the waste results in different products of pyrolysis as well as thermal and chemical characteristics. The results shown in Figures 15.9 and 15.10 show that the presence of paper in the waste provides a major role in...

Stabilization of Polymers

Polyolefins In addition to stabilization of polyolefins against thermal oxidation to reduce the sensitivity to light, stabilization against exposure to light is required for articles to be used outdoors as well as those intended for indoor use 93 . Light stabilizers include UV absorbers of the benzotriazole and the benzophenone types (except for thin sections), HALS, and nickel-containing stabilizers. The latter are used for thin sections such as tapes and films and for surface protection. The...

Typical Gross Energies For Polymer Production

Typical values for the production of a number of different polymers are given in Table 3.2. These values are based on practices in plants across Europe but, given the similarity of technologies used in polymer production worldwide, there is no reason to suppose that different results would be obtained elsewhere when a correction has been made for the fuel infrastructure. The actual values vary from plant to plant. In practice the direct energy consumption varies by 10 and, when the fuel...

Types of Stabilizers

The commercialization of many types of organic polymers for use in outdoor applications has been possible due to the successful development of stabilizers that function in different ways. Some control the amount of actinic radiation that reaches the bulk of the polymer and others inhibit the chemical reactions that follow absorption of the radiation. The former include inorganic pigments and carbon black, usually referred to as light screeners, and ultraviolet absorbers. The degradation...

Fire Properties of Polymers

The release rates of heat and products from the combustion of solid polymers are expressed as 21, 22 Gj (yj AHg)(q'e + qf - ) fj(* AHg)(q'l + qf - ) (11.7) Qh (AHch AHg)(q> + f - ) x(AHr AHg)( + f - q ) (11.8) where G j is the mass generation rate of product j per unit surface area of the polymer (g m2 s), y is the yield of product j (g g), fj14 is the generation efficiency of product j, j is the maximum possible mass stoichiometric yield of product j (g g), Qc'h is the chemical heat release...

Selective Dissolution

The solubility of polymers is highly solvent and solution temperature dependent 76 . As a result, some of the early pioneering work on plastics recycling examined selective dissolution of polymers as a means to separate different plastics from mixtures 2, 75, 93-95 . Various plastic-solvent combinations are shown here PVC esters, ketones, chlorinated hydrocarbons, tetrahydrofuran ABS aromatics, ketones, chlorinated hydrocarbons, tetrahydrofuran PC chlorinated hydrocarbons, dimethylformamide PS...

Polystyrene PS

The polystyrene chromophore absorbs very little terrestrial solar radiation. The cutoff varies with thickness but is considered to be at 280-300 nm. The formation of a charge-transfer (CT) complex between oxygen and polystyrene can extend the absorption to 340 nm or longer wavelengths 24 , and absorption of commercial grades has been reported to extend into the visible region to wavelengths as long as 500-550 nm 25 . On exposure to the environment, the UV visible radiation absorbed by the...

Underhood Polymers

Polymers used under the hood have to be able to withstand very high temperatures. In a typical vehicle temperatures can get as high as 125 C under the hood Figure 17.7. Silverado composite pickup box. Figure 17.7. Silverado composite pickup box. during operation. In a turbo diesel they can get as high as 150 C. Therefore, the choice of available polymers and the extent of their use under the hood is more limited. Rubber materials are typically used for hoses. Polymers are also used for...

Light Sources in Laboratory Accelerated Test Devices

The light sources commonly used for laboratory-accelerated weathering tests include filtered xenon arcs, two types of filtered carbon arcs, fluorescent UV lamps, and metal halide lamps. The spectral power distributions are shown in Figures 8.3 through 8.6 in comparison with solar radiation. The spectral emission characteristics of the sources differ significantly in both the UV and visible regions. Filtered Xenon Arcs Xenon arc radiation appropriately filtered for the UV region closely matches...

Polymer Recovery Recycling Resource Conservation And Integrated Resource Management As Global Concepts

The previous section highlighted the different forms of plastics recycling and noted that some parties differentiate plastics recycling for material recovery from plastics recycling for fuel or energy recovery by designating energy recover and sometimes fuel recovery as resource recovery rather than recycling. As noted above, Japan usually includes thermal recycling in its definition of plastics recycling, while Germany does not. Responsible arguments can be made on both sides of this...

Environmental and Safety Issues on PVC

Over the years, two major controversial issues have been associated with large-volume use of PVC plastics. The first has to do with the fate and health impacts of Figure 2.8. Flow diagram for suspension or emulsion polymerization of vinyl chloride. Figure 2.8. Flow diagram for suspension or emulsion polymerization of vinyl chloride. additives used in vinyl products, particularly the phthalates used as plasticizers and the heavy metal compounds used as thermal stabilizers. Potential toxicity and...

Automated Sorting of Plastic Bottles and Electronic Parts Using NIR

Plastic Figures With Moving Body Parts

As previously noted, many commercial plastic bottle sorting lines use near-infrared spectroscopy to accurately ID bottles by resin type at very high speed. Figure 14.10. Schematic of X-ray fluorescence method for the identification of heteroatoms additives in postuse plastics 70 . Figure 14.10. Schematic of X-ray fluorescence method for the identification of heteroatoms additives in postuse plastics 70 . Figure 14.11. X-ray fluorescence instrument used in plastics recycling. Photo courtesy of...

Common Thermoplastics

Common Molecular Weights

The global production of plastics has grown exponentially over recent years and therefore correlates quite well with the population growth. The world production of resins, which was insignificant a mere half a century ago, now stands at about 132 million metric tons annually. Figure 2.2 illustrates this exponential growth in production and shows how it correlates with the increase in global population. If the linear relationship shown in the figure holds in the future, it might be used to...

Early History Of Plastics Recycling Pre1990

Four events focused attention of plastics recycling prior to 1990 see Table 14.1 . The first was the oil crisis of the early 1970s. The synthetic rubber and plastics industries largely depend on petroleum and natural gas for both their energy needs and feedstock requirements. When the price of a barrel of oil began to skyrocket in the early 1970s, efforts turned to reusing the energy content or material content of plastics as an alternative to purchasing oil from oversees markets. This...

Marking Of Plastic Packages And Products 1461 Physical Marking

To facilitate the manual sorting of plastic packages and products for recycling, various methodologies have been developed to place an identifying mark on the package or product to identify the type of plastic. In practice, the development of fast automated sorting of plastic bottles and rapid flake sorting of commodity and engineering plastics has limited the value of these types of markings. Nevertheless, since some curbside bottle collection programs still accept some but not all types of...

Degradation Of Plastics At

Depending on their chemical structure, plastic materials undergo a combination of thermal oxidation, photo-oxidative degradation, biodegradation, and in some instances even hydrolysis on exposure to the marine environment. Common types of plastics encountered in the marine environment, however, break down primarily through photothermal oxidation processes. The chemical pathways associated with the weathering of plastics at sea are essentially the same as those encountered in outdoor exposure....

Polystyrene Destruction Temperature

Case of polypropylene the exothermic region follows endothermic region. The exothermic region evolves from the combustion of gases evolved from the initial pyrolysis of the material. The TGA results on polystyrene show that this material almost does not have any impurities, and at high heating rate in oxidative conditions the thermal decomposition does not follow the usual smooth decay compare the TGA curves in Figs. 15.33 and 15.35 . Temperature C Figure 15.33. Thermal decomposition of...

Future Developments

This chapter is limited in scope in that there are other materials currently being developed and new materials that will be developed in the future. Various biodegradation testing has been performed on these materials 48-154 . In addition to the creation of new materials, the tailoring of properties to meet specific requirements will be accomplished through blending of two or more biodegradable polymers together and or compounding with biodegradable plasticizers and or biodegradable...

Depolymerization of Nylons

Because of the higher value of nylon resin in comparison with other polymers used in carpet, nylon carpet has been looked at as a resource for making virgin nylon via depolymerization. The majority of polyamides used commercially are nylon 6,6 or nylon 6, and the largest supply of waste for recycling of nylons is obtained from used carpets. The waste carpets are collected, sorted, and then subjected to a mechanical shredding process before depolymerization. Hydrolysis of Nylon 6 A process for...

Polyesters

The photooxidative stability of aliphatic polyesters is generally higher than that of polyolefins, although similar degradation mechanisms are involved. The thermoplastic aromatic polyesters, polyethylene terephthalate PET and polybutylene terephthalate PBT , are intrinsically more light stable than polyurethanes or polyamides. However, prolonged weathering alters the chemical and mechanical properties because of chain scission at the carbon-oxygen single bond of the ester group in the polymer...

Disposal Of Waste Plastic Films

Disposal of plastic films used for greenhouses, mulches, and silage bale wrapping do have some associated problems. Farmers dispose of these plastics through one of the two methods on-site land filling and burning. Though recycling is a good way to resolve this problem, the main hurdle in recycling is the cost involved in collection, transportation, and cleaning operation. Moreover, some agri-films contain as high as 50 contamination level by weight. Contamination comes from silage juices,...

Hazardous Air Pollutants HAPs and Right to Know Regulations

Title III Air Toxics Program of CAAA-90 directs EPA to evaluate and control the emission of HAPs. Among the 189 compounds identified in CAAA-90 as hazardous HAPs list , Brezinski 15 identifies 24 that are used in coatings, 17 organic compounds, 6 metal salts, and ammonia. Some of the 17 organics are used as monomers in binder synthesis and therefore are not emitted to the atmosphere. The EPA has authority to delete or add compounds to the list, and industry groups may petition EPA to take...