Plasticizers environmental considerations

Environmental Considerations. The phosphate flame retardants, plasticizers, and functional fluids have come under intense environmental scmtiny. Results pubUshed to date on acute toxicity to aquatic algae, invertebrates, and fish indicate substantial differences between the various aryl phosphates (159—162). The EPA has summarized this data as well as the apparent need for additional testing (147). 

The foUowing references are useful for information on environmental considerations and recycling. PVC s Environmental Profile Fallay vs. Fact, The Vinyl Institute, a Division of The Society of the Plastics Industry, Inc., Mordstown, N.J., July 1995. 

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

Environmental Considerations in Product Design and Processing, GE Plastics. 

Tetrahydrofuran (THF) is produced by decarbonylation of furfural to furan followed by catalytic hydrogenation. THF is applied as a solvent for resins and plastics, film castings and adhesives. THF also acts as a solvent in different fine organic syntheses on a commercial scale and as a chemical intermediate. Environmental demands increase the THF application cost because THF users must install solvent recovery systems. A high price and environmental considerations will limit the future growth of THF market. 

Hoop-stress equations for two typical press-fit situations are shown in Figure 5-39. The allowable design stress will depend upon the particular plastic, the temperature, and other environmental considerations. A simpler, though less accurate, method of evaluating press fits is to assume that the shaft will not deform when pressed into the hub. This is reasonably accurate when a metal shaft is used in a plastic hub. The hoop strain developed in the hub is then given by... 

Hoop-stress equations for press-fit situations are used. Allowable design stress or strain will depend upon the particular plastic, the temperature, and other environmental considerations. Hoop stress can be obtained by multiplying the appropriate modulus. For high strains, the secant modulus will give the initial stress the apparent or creep modulus should be used for longer-term stresses. The maximum strain or stress must be below the value that will produce creep rupture in the material. There could be a weld line in the hub that can significantly affect the creep-rupture strength of most plastics. 

Due to the influence of environmental considerations, plastics recycling is a growing economic activity. The need to open up new channels for discarded packaging has stimulated the recycling of plastics to produce new packaging materials. Such technical processes are being developed for the most widely used polymers polyolefins, polystyrene (PS), polyvinyl chloride (PVC) and PET. 

Plastic materials are sensitive to environmental conditions. Environmental considerations include exposure to UV, IR, X-ray, high humidity, weather extremes, pollution from... 

Future trends in the use of plastics for automotive applications will be influenced by a number of important factors. Cost and weight reduction will remain an important driver for the motor manufacturers, which will favour plastic instead of metal. Environmental considerations will play an increasingly important role in terms of emission standards and the need to increase plastics recycling from end-of-life vehicles. Finally, there will be increasing demand for higher quality materials and greater use of safety and comfort features in the average car. 

It follows that there are three reasons why the use of degradable plastics in place of conventional packaging plastics in landfill disposal is encouraged by both financial and environmental considerations. 

Since the first application of turbocompressors (Figure 4-1) in large-scale production of nitric acid as a raw material for fertilizers, explosives, plastics, and a variety of other chemical products, the requirements on processes as well as on rotating equipment have become increasingly demanding. Environmental as well as economic considerations have heavily influenced the development of such plants. 

---