The methods commonly used in determining the elements in the polymer

When a compound is connected with the same compound is formed of a continuous chain that has certain characteristics. In a simple sense that I explain what is called the polymer. As has been mentioned in books written in general polymer as a polymer composed of long strands of each monomer binding to the monomer. The length of the string or chain can reach hundreds or even thousands of interconnected monomer. In its website, wikipedia writing A polymer is a large molecule (macromolecule) composed of repeating structural units. These sub-units are typically connected by covalent chemical bonds. Although the term polymer is sometimes taken to refer to plastics, it actually encompasses a large class of compounds comprising both natural and synthetic materials with a wide variety of properties.

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In the current technological developments, many experts in physics, chemistry and polymer material that is the future of materials that are easy to come by. So great expectation addressed to polymeric materials to you, I am curious as well as a lot of people. No wonder that many experts in physics, chemistry, and material has been doing various kinds of research in the field of polymer so that the polymer at the present time this is a category of commercial polymers, such as call it petroleum, plastic gutter pipe PVC, textile polymers, polymer electronics and various other types.

However, in this article we will discuss what is called the polymer but rather how the methods are generally made by people to determine the constituent elements of the polymer. Of course as we know, the formation of a polymer or polymer synthesis / polymerization reactions of polycondensation and polymerization, which is then divided into a variety of methods. Because there are so-called synthetic polymer which constituent elements must exist and how to identify these polymers. The following methods are commonly used by experts that I took from the book by Mr. Anton J. Hartomo:

Classical methods. By performing the cremation-gray, fusion, acid digest or acidification and digest the bomb to the polymer.

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By using the cremation-gray method consists of several ways:

• Cremation without catalytic substances. The process of cremation is done by burning the polymer in a platinum crucible with controlled conditions (as polymer), dissolved in an aqueous reagent, and then analyzed by spectrophotometry. This method is cumbersome and time consuming. Effectiveness of these elements can be different after that. Analysis of the alkali metal is more critical than on the transition metal catalyst.
• Cremation with catalytic substances. The process of cremation is required where the elements are going to be analyzed may be lost when the process is carried out. For example, copper can be reduced and attached to the crucible wall. that is why it was added a solution of inorganic salts, for example magnesium nitrate. When the bulb, the said elements in a matrix of magnesium oxide awake so easily dissolved in a suitable acid and analyzed. The addition of inorganic salts and acids taken in the presence of organic solvent (alcohol) as appropriate.
• At low temperatures the cremation furnace. The process is conducted in a furnace with air oxygen is activated by a cloud of electric charge or with ultraviolet light. Active oxygen to burn the polymer, and the risk of loss of the element being analyzed is smaller because the temperature is lower. Examples of use in the determination of rare metals in the polymer PP, PS and so on.

Then the fusion method can be performed using sodium carbonate, sodium bisulfate, and sodium peroxide. Of fusion with sodium carbonate is very good for the polymer which when in the incandescent-issued gas / vapor acids, such as PVC. Steam trap can be determined with a solid base in the reagent. Ash residue is dissolved in nitric acid, diluted acetone, potentiometric titration using standard silver nitrate.  

Digest method (Kjehldahl) acid. By using this method in addition to the determination of organic nitrogen, more or less the method is also used except in special cases. While oxygen to the combustion vessel used in the analysis of polymers such as the determination of sulfur in the polyolefin, determining chlorine in the rubber khlorobutil and PVC, phosphorus in polyolefins. 

Instrumental Methods of Engineering Analysis. This method is used to analyze the elements in the polymer consist of non-faulty techniques such as X-ray fluorescence and neutron activation analysis, as well as destructive techniques (sample described with specific reagents) such as atomic absorption spectrometry, emission Spectrograph, flame photometry, polarography, and etc..

• X-ray fluorescence spectrometry. Analysis instrument was used for the determination of micro amounts of metal or non metal; also for the content of metals such as cadmium selenide pigments in polyolefins. The advantage lies in the technique that does not destroy the sample, making the specimen is easy, fast and the measurement of content of chemical elements do not depend on the state of incorporation. However, drawbacks include the excitation of many disorders other elements in the matrix polymer. This method is often applied to the determination of industrial elements chlorine, bromine, titanium, aluminum, sodium, potassium, calcium, magnesium and vanadium on a hot plate of felt-PP and PE.
• Neutron activation analysis. This analysis technique can determine the various elements such as chlorine in polyolefins, metals in PMMA, the total oxygen in the copolymer and the PE-vinyl acetate PE-ethyl acrylate as well as the polyolefin. This method is superior because it is very sensitive and hassle free. Disadvantage, must be made in nuclear reactors. However, the results are very good and reliable.
• Atomic absorption spectroscopy (AAS). Often used for metal determination. Samples prepared in the form of an appropriate solution. Certain elements (As, Sb, Hg, Se, Sn) after the polymer has the digest, transformed into a hybrid form of gas using SnCl2 reagent or sodium borohydride.
• Electron probe microanalysis. For this method is used to determine the metal inclusions in the polymer film and sheet. Samples were fired with a narrow beam of X-ray and electron scattering a certain frequency beyond scrutiny. Scattering image corresponding atomic number elements. X-ray beam emitted is detected and enumerated with a special tool or using the detector.

By using the above methods can be determined qualitatively or quantitatively, or in both the qualitative and quantitative elements of the polymer. The goal of science can be used both in order to identify the type of polymer that is not known or commercially in order to control the process. Both of the above techniques of classical technique and modern techniques that use instruments. For so this article, may be beneficial to us all. 

 

Reference:

Penuntun Analisis Polimer Aktual work by Anton J. Hartomo. Penerbit Andi Offset Yogyakarta.

http://en.wikipedia.org/wiki/Polymer