Plastics, comparison with other

Typical values for the principal properties of cellulose acetate compounds are tabulated in Table 22.2 in comparison with other cellulosic plastics. Since cellulose acetate is seldom used today in applications where detailed knowledge of physical properties are required these are given without further comment. 

Plastics have many advantages. Included are the facts that they have the lowest energy consumption in the recycling processes of about 2 MJ/kg (2 to 2.5 MJ/I) and when incinerated the highest recovery energy content exists of about 42 MJ/kg. Some comparisons with other materials are provided. (1) Processing waste paper requires 6.7 MJ/kg and as a general rule about twice as much paper is needed compared to plastics for... 

Adhesives offer both advantages and disadvantages in comparison with other methods of assembly, some of the most important of which are presented in summary form at the conclusion of this chapter. (The chapter as a whole comprises an introductory section, a summary of theoretical considerations underlying the effective use of this approach, a review of the types and typical compositions of adhesives suitable for bonding plastics ( solvent-based , water-based , hot-melt , and reactive ), requirements and methods for treating the surfaces in preparation for bonding, and a number of examples of the successful use of adhesives.)... 

SPS has high a melting point almost comparable to those of other engineering plastics (Table 18.2). In comparison with other crystalline engineering thermoplastics, of particular interest is that SPS has the lowest specific gravity and dielectric constant. 

Researchers [6] showed that the microstructure of RubCon has elastic, elastic-plastic, and viscous phases. The amount of elastic in the composite is less in comparison with others, and consequently deformability of RubCon at action a long-term and a short-term loadings in the greater degree is determined by elastic and elastic-plastic deformations. The increase of the strength of RubCon and the modulus of elasticity at compression and the decrease of its ultimate deformations at negative temperatures can be explained by increases in viscous phase viscosity and partial transformation of an elastic-plastic phase of a composite in elastic. The increase in the elastic phase results in embrittlement of the composite but no changes in its stress-strain state. 

These resins may be blow molded to yield excellent containers for carbonated beverages. In addition, they show a desirable low level of transmission of carbon dioxide, oxygen, and water vapor in comparison with other plastics available today. 

Electrical properties of PPS compounds are summarized in Table II. The dielectric constant of 3.1 is low in comparison with other plastics. Similarly the dissipation factor is low. Dielectric strength is quite high ranging from 500 to 600 V/mil for the various compounds. Thus, both filled and unfilled PPS materials are excellent electrical insulators. 

Plastics and reinforced plastics have many virtues, but in comparison with other structural materials, outstanding high temperature resistance is not one of them. Users must consider their likely response to high temperatures. The same goes for rapid changes in temperature, even when the maximum use temperature expected comfortably exceeds the service temperature. 

Pullulan in aqueous or moistened powder form can be converted into odorless, transparent and tenacious films by any usual method. In comparison with other films, these films have remarkably low oxygen permeability and surpass others as oxidation-preventive barriers. Moreover, the films can be prepared with water as the sole plasticizer. A slight addition of polyhydric alcohol will lead to the production of more flexible films, if desirable. Pullulan with a molecular weight exceeding 150,000 is preferable for film formation. 

The estimate of the future market size can be made in various ways— projection of historical data, comparison with other factors such as GNP where a relationship can be established (e.g. per capita usage of plastics and per capital GNP), and detailed user surveys. 

Figure 3.19 Vickers hardness of crosslinked PABA in comparison with other materials, a functionally graded polymer composite with 45 % SiC b heat treated crosslinked PABA c common hard plastics including PVC, PMMA, polycarbonate, polystyrene and acetal d heat treated polyaniline (polyaniline). (Reprinted with permission from Chemistry of Materials, 17, 3803. Copyright (2005) American Chemical Society.)...

Due to plastics advantages in comparison with other materials, they have been extensively adopted in food packaging. These advantages are reflected in the physical. 

In comparison with other additives used in packaging materials, plasticizers focus attention as they need to be used in high amounts in glassy polymers, up to 50 wt% in PVC and up to 30 wt% in PLA to reach the expected mechanical properties. 

Conditioning Dry specimens in an oven for 24 1 h at 50 2°C, allow to cool to ambient temperature in the desiccator and weigh to the nearest 1 mg. Specimens of a material whose water absorption value is appreciably affected by temperatures close to 110°C, shall be dried in an oven for 24 h at 50 3°C, cooled in a desiccator, and immediately weighed to the nearest 0.001 g. Specimens of a material whose water absorption value is not appreciably affected by temperatures up to 110°C, shall be dried in an oven for 1 h at 105 to 110°C. (No weighing requirement is given in the method however the specimen should be weighed immediately to the nearest 0.001 g.) When data comparisons with other plastics are desired, the specimens shall be dried in oven for 24 h at 50 3°C, cooled in a desiccator, and immediately weighed to the nearest 0.001 g. 

Figure 8.1 illustrates a flow diagram of the density and solvent separation of PVC from other plastic materials. During density separation, there is the possibility that materials of similar density may separate and settle along with the PVC. Using this method 5-8% of the PVC is soluble, and therefore a 12 kg sample can be used for the separation of PVC, which is a major quantity in comparison with other plastics. 

The mechanism of degradation differs for different types of material, and it is outside the scope of this book to try to compare zinc with plastics, concrete, wood, or other nonmetals. Some comparisons with other metals can, however, usefully be made. 

In comparison with other thermosetting polymers, epoxy resins are more expensive but show better mechanical properties, lower shrinkage, and higher resistance to moisture absorption and to corrosive environments. These good physical properties and their durability in service help to provide a favorable cost-performance ratio when compared to other thermoset plastics. 

Figure 6-34. A comparison of plastic composites with other materials.

ZiEBiK, A. and Stanek, W. (2001) Forecasting of the energy effects of injecting plastic wastes into the blast furnace in comparison with other auxiliary fuels. Energy, 26 1159-1173. 

In other cases, bioplastics producers make use of LCA to highlight the environmental performance of their products, not necessarily by comparison with other alternatives. This is, for instance, the case of ISO type III environmental declarations, such as EPD, which have been published for corn starch-based plastics [8]. Again, the EPD is a good instrument for the marketing and communication of products such as bioplastics, which built their commercial success on environmental performance and being perceived as more sustainable by clients and consumers. 

The so-called plastic rechargeable battery is probably the most widely publicized potential application for conductive polymers, and has received the greatest share of research and development funding in comparison with other applications of this class of polymers. The... 

Sol-gel process This is a chemical method that makes it possible to obtain coatings at much lower temperatures than the conventional processing methods. In comparison with other methods such as PVD, CVD, evapora-tion/condensation, and so on, it only requires simple equipment and enables application on substrates that are sensitive to treatment at high temperatures, such as many metals and plastics. 

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