Plastics environmental concerns

Antimony tris(isooctylthioglycolate) has found use in pipe formulations at low levels. Its disadvantage is that it cross-stains with sulfide-based tin stabilizers (122). Barium—zinc stabilizers have found use in plasticized compounds, replacing barium—cadmium stabilizers. These are used in mol dings, profiles, and wire coatings. Cadmium use has decreased because of environmental concerns surrounding certain heavy metals. 

The growth of demand for benzoic acid is expected to increase at a rate of between 1 and 2% per year (17). Glycol dibenzoate plasticizers have been growing at close to 10% annually for the past several years, in part due to environmental concerns with regard to phthalate plasticizers (qv). The growth of the diet soft drink market has increased the demand for sodium and potassium benzoates (17). 

In the past few years many changes have occurred in the packaging materials utilized for distilled spirits. Traditionally, distilled spirits have been packed primarily in glass containers of approved ATF sizes. Over the last 5—10 years, plastic containers, primarily poly(ethylene terephthalate) (PET), have been utilized by increasing numbers of distillers. Because of environmental concerns, the last two years have seen a change back to glass on some of these package sizes. However, the 50 mL miniature bottie continues to be primarily packed in PET plastic containers. 

The forecasts made in 1985 (77) of 8—8.5% worldwide aimual growth have not materialized. The 2 x lOg + /yr engineering plastic production reported for 1985—1986 has remained fairly constant. Whereas some resins such as PET, nylon-6, and nylon-6,6 have continued to experience growth, other resins such as poly(phenylene oxide) have experienced downturns. This is due to successhil inroads from traditional materials (wood, glass, ceramics, and metals) which are experiencing a rebound in appHcations driven by new technology and antiplastics environmental concerns. Also, recycling is likely to impact production of all plastics. 

None arc inogenic mineral oil-based plasticizers and extender oils are being utilized more and more in elastomer and tire formulations and this interest is prompted by the health and environmental concerns as well as by the coming EU legislation. 

PET competes effectively with PVC in medical packaging because of its strength and superior resistance to sterilizing effects. However, it is a poor moisture-vapor barrier and its enhancement by PVdC is not viable because of environmental concerns about plastics that contain chlorine. 

Plastic products are known to eventually break down into smaller and smaller pieces (nanoparticles) until they are small enough to enter the cells of living organisms. Because the amount of discarded plastic is so substantial, nanoplastic particles pose an emerging environmental concern. The health effects of nanoplastics are not thoroughly understood, but polystyrene particles up to 240 nm in diameter have been proven to be transportable through placental cells [52],... 

TABLE II. Chemicals of environmental concern and plastic additives with analogous structures... 

Every year millions of cubic meters of ready-mixed concrete are returned for disposal in dump sites. There are now increasing environmental concerns and restrictions regulating the disposal of returned plastic concrete. In the last decade, environmental protection agencies in Europe and North America have classified both returned plastic concrete and truck wash water as hazardous waste. Consequently, the conventional methods of disposal in slurry tanks and landfill sites have become redundant, and disposal of plastic concrete is now a major problem for the ready-mixed concrete industry [102]. 

Concrete may use plasticizers (e.g., sulphonated melamine and naphthalene formaldehyde condensates), air-entraining agents (aIkyI/aryl sulfonate surfactants), retarders (hydroxy carboxylic acids such as polyethylene glycol mono-p-nonylphenyl ether) and surface washes (benzalkonium chloride) (RAIA 1997). Little has been published on air emissions from concrete additives, their leaching into surface waters appearing to be of greater environmental concern (Ruckstuhl, 2001). 

In the early 1970s, environmental concerns about the disposal of plastics generated considerable interest in the development of degradable materials.37 This concern... 

In an age of increasing environmental concerns, many of the tools that formulators had utilized in the past are no longer acceptable. Use of solvents has been drastically curtailed. Plasticizers must often be used in limited amounts. Regional regulations place demands that total VOC emissions be kept to a minimum. Certain catalysts and additives are discouraged because of safety or health issues. 

Next, a crisis in plastic bottles occurred in early 2008 in the U.S., Canada and elsewhere. Consumers are concerned about the use of BPA or bisphenol-a, which is commonly used in the manufacture of the hard, clear polycarbonate plastic bottles used for juices, drinks and other liquids. Many manufacturers promptly announced they would no longer use BPA. Environmental concerns, health concerns and consumer backlash regarding packaging will grow in coming years. 

In particular, as far as the plastic catalytic degradation is concerned, there are various possible scenarios. In large urban areas the best approach probably is to build a plastic waste pyrolysis plant in an acceptable near area at not to great distance, in order to minimize transport cost of the plastic waste. In that case, safety and environmental concerns of such a new plant should first be denied with satisfactorily before the new plant can get the go-ahead. Near refineries however, the best approach might be to co-feed plastic waste with oil fractions into refinery crackers, or even have a unit of pure thermal pyrolysis first with the produced wax-type fraction to be upstaged in another reactive refinery process. In the first case of co-feeding, a lot of research has to be carried out, addressing aspects of defluidization mainly, before an alteration of a process of the scale of FCC units can go ahead. 

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