Other properties tests

Composition is normally expressed by a distillation curve, and can be supplemented by compositional analyses such as those for aromatics content. Some physical properties such as density or vapor pressure are often added. The degree of purity is indicated by color or other appropriate test (copper strip corrosion, for example). 

MohsAn early (1822) hardness comparison test involved assigning a relative number to aH known materials (usuaHy minerals and pure metals) by virtue of their relative abHity to scratch one another. The results of this classification are not relatable to other properties of materials or to other measures of hardness. As a result of this limited useflilness, the Mohs hardness test is primarily used for mineral identification. Some examples of the Mohs hardness scale, which ranks materials from 1 to 10, are Hsted in Table 6. 

The viscosity of the spray oil, as measured by the Saybolt test, also determines its safety on plants. Other properties being equal, oils of low viscosity ate safer to use on foHage than those of high viscosity. For dormant sprays on deciduous trees, oils with viscosities between 100 and 200 Saybolt universal seconds (SUs) at 37.8°C are considered satisfactory. A lower range is often used in colder and a higher range in warmer areas. 

Ionomer resins are produced in multiple grades to meet market needs, and prospective customers are provided with information on key processing parameters such as melt-flow index. Nominal values for many other properties are Hsted in product brochures. The ASTM test methods developed for general-purpose thermoplastic resins are appHcable to ionomers. No special methods have been introduced specifically for the ionomers. 

Initial evaluations of chemicals produced for screening are performed by smelling them from paper blotters. However, more information is necessary given the time and expense required to commercialize a new chemical. No matter how pleasant or desirable a potential odorant appears to be, its performance must be studied and compared with available ingredients in experimental fragrances. A material may fail to Hve up to the promise of its initial odor evaluation for a number of reasons. It is not at all uncommon to have a chemical disappear in a formulation or skew the overall odor in an undesirable way. Some materials are found to be hard to work with in that their odors stick out and caimot be blended weU. Because perfumery is an individuaHstic art, it is important to have more than one perfumer work with a material of interest and to have it tried in several different fragrance types. Aroma chemicals must be stable in use if their desirable odor properties are to reach the consumer. Therefore, testing in functional product appHcations is an important part of the evaluation process. Other properties that can be important for new aroma chemicals are substantivity on skin and cloth, and the abiHty to mask certain malodors. 

This allows the production of master curves, which can be used to estimate changes ia modulus or other properties over a long period of time by shorter tests over different temperatures. 

Four modes of characterization are of interest chemical analyses, ie, quaUtative and quantitative analyses of all components mechanical characterization, ie, tensile and impact testing morphology of the mbber phase and rheology at a range of shear rates. Other properties measured are stress crack resistance, heat distortion temperatures, flammabiUty, creep, etc, depending on the particular appHcation (239). 

Regardless of whether the fabric stmcture is woven or knitted, accurate characterization of constmction parameters is necessary to evaluate test results for other properties and to explain differences noted when comparing test data from fabrics of different constmctions. 

Other Properties and Tests. The other physical and chemical properties of porcelain enamels can be evaluated as shown below ... 

Many additional consistency tests can be derived from phase equiUbrium constraints. From thermodynamics, the activity coefficient is known to be the fundamental basis of many properties and parameters of engineering interest. Therefore, data for such quantities as Henry s constant, octanol—water partition coefficient, aqueous solubiUty, and solubiUty of water in chemicals are related to solution activity coefficients and other properties through fundamental equiUbrium relationships (10,23,24). Accurate, consistent data should be expected to satisfy these and other thermodynamic requirements. Furthermore, equiUbrium models may permit a missing property value to be calculated from those values that are known (2). 

Part AM This part lists permitted individual constnic tion materials, apphcable specifications, special requirements, design stress-intensity vafues, and other property information. Of particular importance are the ultrasonic-test and tou ness requirements. Among the properties for which data are included are thermal conduc tivity and diffusivity, coefficient of theiTnal expansion, modulus of elasticity, and yield strength. The design stress-intensity values include a safety factor of 3 on ultimate strength at temperature or 1.5 on yield strength at temperature. 

As might be expected of a somewhat polar thermoplastics material, mechanical, electrical and other properties are strongly dependent on temperature, testing rate and humidity. Detailed data on the influence of these Vciriables have been made available by at least one manufacturer and the following remarks are intended only as an illustration of the effects rather than as an attempt at providing complete data. 

Obtain all available information about the material. If it is a surplus or off-specification product, obtain an analysis or a Material Safety Data Sheet. If it is a waste, check for previous analyses, and if none exists, obtain one. (Even if a previous analysis exists, consider running a few screening-type field analyses for confirmation of important properties such as pH, redox potential, or other oxidizer test such as cyanide, sulfide, and flashpoint.)... 

It should be noted that although Table 1.8 gives specific values of Tg for different polymers, in reality the glass-transition temperature is not a material constant. As with many other properties of polymers it will depend on the testing conditions used to obtain it. 

For preventing items from losing their identity - once the identity is lost it is often difficult, if not impossible, to restore complete identification without testing material or other properties. 

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 ... 

The mechanical properties of plastics enable them to perform in a wide variety of end uses and environments, often at lower cost than other design materials such as metal or wood. This section reviews the static property tests. Chapter 5 provides more information on the meaning of these type data. 

Opacity or transparency is important when the amount of light to be transmitted is a consideration. These properties are usually measured as haze and luminous transmittance. As reviewed haze is defined as the percentage of transmitted light through a test specimen that is scattered more than 2.5° from the incident beam. Luminous transmittance is the ratio of transmitted light to incident light. Table 5-7 provides the optical and various other properties of different transparent plastics. 

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