Synthetic polymers disadvantage

Furthermore, the major disadvantages encountered in GC/MS, i.e. undetectability of synthetic polymers and unpredictable interferences due to their presence, may be avoided using the Py-GC/MS technique. All these aspects strongly suggest how useful, and in some cases fundamental, analytical pyrolysis is in the analysis of complex samples, such as those collected from works of art, to implement and support results obtained with wet chemical pretreatment followed by GC/MS analysis. 

Microfiltration units can be configured as plate and frame flat sheet equipment, hollow fiber bundles, or spiral wound modules. The membranes are typically made of synthetic polymers such as Polyethersulfone (PES), Polyamide, Polypropylene, or cellulosic mats. Alternate materials include ceramics, stainless steel, and carbon. Each of these come with its own set of advantages and disadvantages. For instance, ceramic membranes are often recommended for the filtration of larger particles such as cells because of the wider lumen of the channels. However, it has been shown that spiral wound units can also be used for this purpose, provided appropriate spacers are used. 

Synthetic polymers have wide application in various industries and in this chapter the application with respect to the textile industry and biomedical field are addressed. These fibers exhibit excellent physical properties such as strength, flexibility, toughness, stiffness, wear, and abrasion resistance (Ikada, 1994). However, synthetic polymers also exhibit some disadvantages that restrict their wider applications. A poor hydrophilicity is the main disadvantage with synthetic polymers and this makes it difficult for the application in textile industry and the biomedical field. 

The simplest examples of so-called functional or functionalized polymers are perhaps those with pendant functional groups. The introduction of pendant functional groups to synthetic polymers, in general, may be achieved by two methods (1) polymerization of monomers with pendant functional groups and (2) chemical transformation of the pendant groups in preformed polymers. Both of them involve advantages and disadvantages, and most of the currently available polymers of this type are pro-... 

A wide variety of synthetic polymer resins can be used as water repeUents for concrete. These include acrylates, epoxies, chlorinated mbber, polyvinylbutyral, urethanes, elastomeric sUicones, and fluoropolymers. They are generaUy appUed from organic solvents or, in some cases, aqueous dispersions or latexes. Some have the disadvantage of inducing gloss and discoloration in the treated masonry. 

The increased interest in energy sensitive polymers probably evolves from the shortcomings of the conventional image recording media-silver halide emulsion. It is both difficult and expensive to apply emulsion films as protective layers or use as printing plates or etch resists. Synthetic polymers are one to two orders of magnitude less radiation sensitive than halide emulsion, but their unique properties of chemical and physical resistance easily overcome this disadvantage, ( ., Table IV). 

In comparison with biologically derived materials, synthetic polymers have several advantages and disadvantages. Since they do not need to be extracted from animal tissue they pose a lower risk of contamination and immunological reaction. Their physical and chemical properties can be better controlled and manipulated. On the other hand, synthetic materials usually do not activate specific cellular receptors and therefore do not by themselves elicit the desired cellular responses such as axonal growth or cell migration. Some materials may even be rejected or encapsulated in scar tissue. 

ProductiOTi and use of polymer products is environmentally disadvantageous wherever other materials perform the same function with less impacton the environment. Which types of materials these may be again depends on the specific function. Depending on the polymer type between 25 and several 100s Ml of non-renewable energy resources are consumed for the production of 1 kg of polymer. In the polymer s end-of-life tuily a fraction of 15-50 MJ, which is embodied in the polymer can be recovered for example as electricity and steam from waste incineration plants. Furthermore, new incineration plants are able to recover quality hydrochloric acid from the chlorine content of the polymers (and of course other non-polymer chlorine inputs). The remainder is lost. Production of synthetic polymers indeed consumes a high amount of energy, of which only a share can be recovered. While polymers are not per se environmentally bad, but in contrast often the better material alternative, they nevertheless must not be wasted, of course. 

The most popular immobilization method is adsorption on a carrier such as diatomaceous earth or a synthetic polymer. The advantage of this method is that the original activity of the enzyme is maintained, but the disadvantage is that the enzyme cannot be used in an aqueous solution. 

Identify Synthetic polymers often replace stone, wood, metals, wool, and cotton in many applications. Identify some advantages and disadvantages of using synthetic materials instead of natural materials. 

In the previous two chapters you learned about two different approaches to the creation of recognition sites in synthetic polymers by molecular imprinting, i.e., via the noncovalent and the covalent approach. Both methods have inherent advantages and disadvantages. 

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