Plastic materialities 129 standardization

It becomes increasingly apparent that color in foods will be measured in one of two ways by abridged spectrophotometry, or by direct color measurement, preferably in terms of the 1931 C.I.E. conventions in either the original C.I.E. color space or one of its more useful transformations. One may also anticipate increased use (when applicable) of carefully prepared plastic material standards which can be cleaned and polished as often as necessary, for nonmetameric matches delimiting tolerances acceptable in a given color grade for a food. 

ASTM is continuing to harmonize its plastics material standards and test methods to international standards. 

ASTM D5045-91, "Plane Strain Fracture Toughness and Strain Energy Release Rate of Plastic Materials," A.nnualBook ofyiSTM Standards, ASTM Puhhcations, Philadelphia, 1993. 

As already mentioned, much of the use for plastics just after World War II was as a cheap substitute for traditional materials, and in other cases the material was used for its novelty value. In many instances the result was detrimental to the industry and it required several years of painstaking work by the technical service departments of the major plastics materials manufacturers before confidence was regained in the use of plastics. Even today the public image of plastics is not entirely positive and the significant contribution of plastics to raising the standard of living and quality of life is not fully recognised. 

Two particular test methods have become very widely used. They are the Vicat softening point test (VSP test) and the heat deflection temperature under load test (HDT test) (which is also widely known by the earlier name of heat distortion temperature test). In the Vicat test a sample of the plastics material is heated at a specified rate of temperature increase and the temperature is noted at which a needle of specified dimensions indents into the material a specified distance under a specified load. In the most common method (method A) a load of ION is used, the needle indentor has a cross-sectional area of 1 mm, the specified penetration distance is 1 mm and the rate of temperature rise is 50°C per hour. For details see the relevant standards (ISO 306 BS 2782 method 120 ASTM D1525 and DIN 53460). (ISO 306 describes two methods, method A with a load of ION and method B with a load of SON, each with two possible rates of temperature rise, 50°C/h and 120°C/h. This results in ISO values quoted as A50, A120, B50 or B120. Many of the results quoted in this book predate the ISO standard and unless otherwise stated may be assumed to correspond to A50.)... 

The initial use was as a blow moulded vessel for vegetable oil candles. However, because of its biodegradability it is of interest for applications where paper and plastics materials are used together and which can, after use, be sent into a standard paper recycling process. Instances include blister packaging (the compound is transparent up to 3 mm in thickness), envelopes with transparent windows and clothes point-of-sale packaging. 

Many abbreviations for plastics materials are in common use. Some of these have now been incorporated into national and international standards, including ... 

In computing ordinary short-term characteristics of plastics, the standard stress analysis formulas may be used. For predicting creep and stress-rupture behavior, the method will vary according to circumstances. In viscoelastic materials, relaxation data can be used in Eqs. 2-16 to 2-20 to predict creep deformations. In other cases the rate theory may be used. 

The dielectric materials interact with the electrical fields and alter the characteristics of the electrical field. In some cases this is desirable and in others it is deleterious to the operation of the system and must be minimized. This is done by both the selection of the material and the configuration of the dielectric. To see how these concepts are applied, an example is presented of one of the major applications of plastics materials, i.e., to insulate wires, and show how a dielectric is designed to meet the service requirements. The specific requirements on a standard wire are ... 

The Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances (UL 94) has methods for determining whether a material will extinguish, or burn and propagate flame. The UL Standard for Polymeric Materials-ShortTerm Property Evaluations is a series of small-scale tests used as a basis for comparing the mechanical, electrical, thermal, and resistance-to-ignition characteristics of materials. 

Test Method. There are several standard methods available to investigate the fungistatic activity of plastic materials (e.g. ISO 846, ASTM G21, ASTM E 1428). In the given study a method has been used which is not yet a standard test method but which is at the moment passing through the official procedure to become an ISO standard The NS A method. 

In order to validate sliding spark spectrometry results, plastic material was collected and the element concentration was determined via AAS after digestion. The samples were used as calibration standards. Additional standards were obtained by manufacturing known amounts of additives in the polymer matrix. Calibrations were made for Cd, Cr, Pb, Zn, Sb, Si and Ti in chlorine-free polymers Al, Ba, Ca, Cd, Pb, Sn, Ti, Zn in PVC chlorine (as PVC) and bromine in polyurethane (PUR). A calibration curve for Br as a flame retardant in PUR is shown in Figure 8.5. 

Flame retardants cause the plastic material to be safer in use in its final form. They are only used when the marketplace requires it in a wide range of applications spanning the construction, moulded parts, sealants, coatings and textile industries. High levels (up to 25 %) of FR are required in polypropylene - one of the most difficult plastics to render flame retardant - to meet standards for certain applications, such as in the... 

An international committee (ISO/TC45) deals with the standardisation of test methods for rubber and the standardisation of rubber product specifications. There is a parallel committee for plastics, materials and products ISO/TC61. Individual countries also have standard setting bodies such as BSI and ASTM. 

Many chlorine producers are having to tolerate impurities originating from standard plastic materials used in membrane technology. Flot chlorine and hot anolyte emerging from the anodic compartment of the cell place tremendous stresses on these plastic construction materials. 

Accelerated exposure equipment may also be used to test for weatherfastness in plastic materials [106], The natural destructive agents inherent in weather are approximated by filtering the radiation emitted by the xenon arc lamp and by spraying the sample with water under standardized conditions [106], Test programs are designed to relate to actual outdoor exposure to rain and humidity. In a standard program, a 3 minute wet cycle typically alternates with a 17 minute dry period. Weatherfastness tests are carried out and evaluated like lightfastness tests the black panel temperature and other parameters are the same in both procedures. 

Australia Australian Standard 2070.6 (1995) (Plastic materials for food... 

To prove the ultimate biodegradability of a biodegradable polymer and that there is no adverse effect on the user or the environment, as well as to successfully market a plastic material as biodegradable, there are international standards in place according to which these materials can be certified. Both Ecoflex and Ecovio are certified worldwide as compostable and are approved for contact with food. 

Compounds containing sulfur and cyanide become a potential source of air pollution when treated with this system. A caustic scrubber may be required to capture the combustion products of these compounds if sulfur and cyanide levels are high enough to exceed health and safety or applicable air quality standards. Metals that are not particularly volatile are not likely to be treated effectively by the TDS. Plastic materials are not recommended for treatment since their decomposition products could cause plugging or foul surfaces. 

Standard test methods for determining aerobic biodegradation of radiolabeled plastic materials in an aqueous or compost environment, ASTM Standard ASTM D 6340-98, ASTM International, West Con-shohocken, PA, 2007. 

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