Substitution by plastics

Another end-use, which has suffered because of weight considerations in the auto industry and substitution by plastics, has been the use of zinc in brass. While the impact of these developments was not severe as in the case of die-casting, it was not until 1994 that the consumption of brass surpassed the levels first reached in 1973. 

However, the high resistance of plastics to media that often destroy metallic materials very quickly has led to their increasing substitution by plastics in numerous important application areas. Yet plastics, too, are less resistant to certain media and, depending on their chemical composition and physical structure, are subject to certain changes that can have both a reversible and an irreversible character [13]. 

Vinyl-Coated Fabrics. Leather substitutes are designed to imitate the appearance of leather with its grain surface. This requirement has been accomphshed by coating substances that are capable of forming a uniform film, and was first met by plasticized poly(vinyl chloride) (PVC). A leather-like material termed vinyl-coated fabric was developed in the 1930s in the United States and Germany. Shortages of leather after World War 11 spurred the expansion of this material. 

There will be import substitution by increased production in China of polyesters, other synthetic textiles, plastics, synthetic rubbers and many chemicals. Beneficial ripple effects of the increased production of indigenous synthetics will be to ... 

The urge of polymer scientists to develop new materials is driven by society s wish to substitute conventional materials by plastics and thereby gain in performance. One reason for the emerging interest in hyperbranched polymers and other macromolecular architectures is their different properties compared to conventional, linear polymers. 

Figure 4. Hot plasticity of sulfide inclusions during hot rolling of steel as a function of oxygen content, Mn/S ratio, rolling temperatures, and substitution by stronger sulfide formers. The hot plasticity is measured in length-to-width ratio of elongation after hot rolling, in longitudinal sections.

Chlorine can be substituted by hydrogen fluoride and boron trifluoride to yield chlorofluorocarbon compounds. This process is applied for producing 1,1-dichloro-l-fluoroethane (14), which is considered as a replacement for trichlorofluoromethane as a blowing agent for plastic foam.18... 

It is clear from this brief list of adhesives on the basis of alkyl-a-cyanocrylates that these adhesive have been modified by replacing the alkyl substitute in the acryl group as well as by introducing various additives characterized by plasticizing or medicinal properties. 

In applications, where aluminum powder is requested (e.g. in powder coatings) or where the rest of the remaining mineral spirit would not be compatible with the application medium (e.g. in printing inks, waterborne coatings and inks, master-batches etc.), the mineral spirit of the press cake is removed in vacuum driers and substituted by any kind of solvent, water, plasticizer, mineral oil or other liquids. 

Dioctyl sebacate (S = 8.7) which is used as a plasticizer for poly(vinyl chloride) is to be substituted by a mixture of tritolyl phosphate (S = 9.8) and aromatic oils (6 = 8.0) on the basis of equal 6 value. Calculate the composition of the mixture. 

If concrete removal is not required or supplementary reinforcing bars cannot be used, external reinforcement can be applied. For instance, steel bars may be encased in a shotcrete layer or steel plates may be bonded onto the concrete surface. Recently, the use of steel plates has been substituted by fibre-reinforced plastics (F. R.P.), that are composite materials with glass, aramide or carbon fibres embedded in a polymeric matrix (usually an epoxy system). F. R.P. are available in the form of laminates or sheets that are bonded to the concrete surface using an epoxy adhesive [11]. They are typically used to improve the flexural and shear strength or to provide confinement to concrete subjected to compression. The... 

An example of substitution by a bio-based product is given by isosorbide, a molecnle bio-sourced from starch. Isosorbide (Figure 1.5) is considered to be a possible alternative, as well as fatty esters of isosorbide, for the replacement of phthalates as plasticizers of PVC [ROQ]. 

Competitions for the biomass are basically solvable by an expansion of the production, an import and a substitution with other (non-biogenic) products i.e. substitution of woody materials by plastics or stones). However, they differ according to the organizational extent and the necessary time periods. 

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