Product testing chemical resistance

Method of Testing Chemical Resistance of Glass Used in the Production of Laboratory Glassware, BS 3473 1962... 

The effects of corrosion on other properties need similar direct assessment in many cases. However, in the absence of accepted standard tests the BS, DIN, ISO tests for laboratory glassware are often used. At the present time, the British Standard BS 3473 Methods of testing and classification of the chemical resistance of glass used in the production of laboratory glassware is being re-issued in six parts, of which the first five parts are identical to recently revised ISO test procedures. There are also corresponding DIN tests in some cases which are very similar. The current situation is ... 

These test procedures and standards are subject to change, so it is essential to keep up to date if one has to comply with them. It may be possible to obtain the latest issue on a specific test (such as a simple tensile test or a molecular weight test) by contacting the organization that issued it. For example, the ASTM issues new annual standards that include all changes. Their Annual Books of ASTM Standards contain more than seven thousand standards published in sixty-six volumes that include different materials and products. There are four volumes specifically on plastics 08.01-Plastics 1 08.02-Plastics 11 08.03-Plastics III, and 08.04-Plastic Pipe and Building Products. Other volumes include information on plastics and RPs. The complete ASTM index are listed under different categories for the different products, types of tests (by environment, chemical resistance, etc.), statistical analyses of different test data, and so on (56,128,129). 

Chlorinated polyether is formulated particularly for products requiring, good chemical resistance. Other materials exhibiting good chemical resistance include all of the fluorocarbon plastics, ethylpentenes, polyolefins, certain phenolics, and diallyl phtha-late compounds. Additives such as fillers, plasticizers, stabilizers, colorants, and type catalysts can decrease the chemical resistance of unfilled plastics. Certain chemicals in cosmetics will affect plastics, and tests are necessary in most cases with new formulations. Temperature condition is also very important to include in the evaluation. Careful tests must be made under actual use conditions in final selection studies. 

The first interactive electronic encyclopedia for users of plastics, materials selection is carried out using 3 search routines. The Chemical Resistance Search eliminates materials that cannot meet user specified chemical resistance requirements. The other search routines ( Elimination and Combined Weighting ) eliminate candidate materials based on 72 properties, falling within one of the following groups General and Electrical, Mechanical, Cost Factors, Production Methods and Post Processing. All data is evaluated and based on independent tests conducted in RAPRA s laboratories. 

When carrying out chemical resistance tests, it is advisable where possible to use the same solution that the product is going to be used in. This will help cover the interpretation of the effects of several different chemicals that may be in a commercial mixture. 

When more than one plastic resin is used to fabricate bottles, it is necessary to demonstrate the equivalency of the container produced using the different resins. In addition, comparative data derived from light transmission, chemical resistance, extractables, and moisture permeation/vapor transmission tests described in the USP should be provided as applicable to the type of product. (For example, moisture permeation for an aqueous dosage form would not be necessary). Whereas the compendia discuss these tests only in the context of polyethylene, the guideline makes no distinction as to the resin used. It also should be verified that copies of letters authorizing FDA reference to appropriate DMFs from manufacturers of the resins used to fabricate bottles and from the bottle fabricator s), if available, are included. Although most resin suppliers include information on extractables data in their DMFs, it should be pointed out that fabricators may have to add release agents or other additives not covered by extractables data in the DMF of the resin supplier. 

End-use stability and performance are the net result of good design and colorant selection. In the case of colorants, end-use stability and performance most often refer to ability to resist attack by chemicals, solvents, heat, weather, and gases and aerosols found in the product environment. The resistance of a plastic product to attack by any of these in a laboratory can produce definitive results. In combination, these elements are difficult to quantify not only in the laboratory but also in actual exposure to them. Thus, testing throughout a project from start to finish is vital to the technical and commercial success of that plastic product. In this chapter the focus is on the role the colorants play in the success. 

Manufacturing processes have evolved dramatically over the last few years. In the late 1980s, 76 /o of hemophiliacs were HCV positive, ° and between 1979 and 1985, approximately 50 /o of hemophiliacs had acquired HIV from plasma-derived FVIII. Since then, however, most U.S.-licensed plasma derivatives have not transmitted HBV, HCV, or HIV as a result of improvements in donor screening and test methods, and the inclusion of effective upstream virus-reduction and terminal virus-inactivation steps in manufacturing processes. Residual risks of virus transmission from plasma-derived products are now largely associated with non-enveloped viruses. " Thus, the need for additional terminal or upstream virus inactivation/removal steps still exists, but the current challenge is to develop cost effective methods against physico-chemically resistant non-enveloped viruses, such as human parvovirus B19. 

In 1975, Chem Systems developed the liquid phase methanol (LPMeOH) process which is based on the low pressure synthesis technology except that the new process is carried out in an inert oil phase [79], The catalytic system used is Cu/Zn0/Al203, that is modified for slurry operation (i.e., attrition resistant, finely powdered, and leaching resistant). The S3.85 and S3.86 catalysts of BASF and EPJ-19 and EPJ-25 catalysts of United Catalysts Inc. were developed for this process [14,19]. The process has been tested for commercial feasibility at a demonstration scale by Air Products and Chemicals, Inc [79]. 

A basic guideline in a choice of corrosion environments during the test of RubCon specimens was their wide spreading into industrial production. Such environments were water, 30% and 70% solutions of sulfuric acid, 5% solutions of phosphoric and acetic acids, 3% solution of nitric acid, 3% and 30% solutions of hydrochloric acid, 10% solutions of lactic and lemon acids, caustic soda and caustic potash, diesel fuel, acetone, 25% water solution of ammonia, 30% solution of copper vitriol, and a saturated solution of sodium chloride. Chemical resistance of RubCon was estimated on test specimens measuring 4 x 4 x 16 cm [21-23],... 

Lastly, selection methodology of fluoropolymers depends on the nature of the application. Fluoropolymers are principally used for chemical resistance, nonstick, and product purity applications. Data search and testing will depend on the application under consideration. Except for screening methods, testing is very application specific. 

Air Product and Chemicals, Inc. (USA) have found out that (in the absence of any topcoat) while the doped electrically conductive form of PAni performed well as a corrosion-resistant coating for carbon steel, the undoped, nonconductive form of PAni performed better. This was determined by electrochemical impedance spectroscopy (EIS), immersion testing (3wt % NaCl) and salt fog testing. Perfect performance of undoped PAni could be understood as follows. From the high pore-resistance value observed (2-10 U) it can be concluded that PAni forms a dense, adherent, low porosity film on carbon steel. Such a film would restrict the access of components required for corrosion to occur ... 

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