ASTM testing procedures

One ASTM test procedure has suggested (24) that foamed plastics be classified as either rigid or flexible, a flexible foam being one that does not mpture when a 20 x 2.5 x 2.5 cm piece is wrapped around a 2.5 cm mandrel at a uniform rate of 1 lap/5 s at 15—25°C. Rigid foams are those that do mpture under this test. This classification is used in this article. 

Mechanical Properties. The performance of various polyester resin compositions can be distinguished by comparing the mechanical properties of thin castings (3 mm) of the neat resin defined in ASTM testing procedures (15). This technique is used widely to characterize subtle changes in flexural, tensile, and compressive properties that are generally overshadowed in highly filled or reinforced laminates. 

Although these materials do not have flash points using standard ASTM test procedures, it is possible that they have flammable limits in air. For example, L-12862 has no flash point, but it does become flanunable in air between concentrations of 2.7 and 11.5 vol %. Several common materials exhibit this type of behavior. 1,1,2 Trichloroethylene does not have a flash point and is shipped as a nonflanunable material, but shows flammability limits between 12.5... 

The rate of peel loading is more important than in lap shear loading, and it should be known and controlled as closely as possible. The rate at which the load is applied is usually specified in the ASTM test procedure. Adhesive thickness also has a significant effect on peel strength values, as does the angle of peeling. 

To meet fabricated dimensional tolerances different approaches are used. They include use of specific fillers and reinforcements and process control (Chapter 3). Popular filler used is short glass fibers (Chapter 15). Over 50wt% of all types of glass fibers used with different plastics and by different processes are used in injection molding compounds. Table 2.2 shows the shrinkage of different unreinforced plastics ad glass fiber reinforced plastics based on ASTM testing procedures. 

The ASTM test procedures referred to above give details for correcting the test data for the added strength due to the membrane, and the decrease in unit stress due to enlargement of the cross-section area of the specimen during the test. These corrections may be made if desired, but are generally not warranted since they are probably less than the precision of the test. 

The following properties, determined by established ASTM test procedures, are of significance ... 

Two separate (and not necessarily related) readouts of the test are (a) flame spread along the surface of the specimen as a distance traveled by the boundary of a zone of flame over time and (b) smoke developed as a change in optical density (as a progress curve of light absorption percent) between the light source and the photoelectric cell mounted in the vent pipe. These data are used to calculate the respective FSI and SDI as described in the ASTM test procedure. The indexes are calculated as relative values to those of select grade oak (FSI arbitrarily set as 100) and inorganic reinforced cement board (FSI set as 0) surfaces under the specified conditions. 

RUBBER AND RUBBER PRODUCTS, NATURAL AND SYNTHETIC ASTM TESTING PROCEDURES... 

The corrosion rates determined in the various tests will vary greatly depending on the alloy being evaluated. Acceptance corrosion rates are not specified in the ASTM test procedures. They must be agreed upon by the supplier and user. Examples of typical acceptable corrosion rates determined for various alloys in ASTM G 28, Practice A are listed in Table 2 [3]. Due to test and material variations, the maximum acceptable rate will be somewhat higher than this nomin2d number. 

Procedures The test procedures for ASTM D-5338-11 involve placing 500 grams of industrial compost soil that has maturity level of 2-3 months into a container vessel greater than 2 liters and less than 5 liters. The ASTM test procedure for industrial compost is explained in more detail in Appendix D. 

A plastic block is weight-loaded against the rim of the disk (line contact) and the wear test is usually between 20 and 30 hours. The plastic samples have dimensions that allow them to be made from plastic flex test bars that are commonly molded out of new plastics to measure their flexural properties. This test is intended to replace the thrust washer test. The ASTM test procedure does not require measurement of counterface wear, but it is always advisable to make this measurement. The disk weighs more than 3 kg, making it difficult to weigh it to measure mass change that occiured in a test Profilometry could be used. 

Each of the fillers in both surface modified and as received condition was mixed with polypropylene and then dried at 110 C for 30 minutes just prior to molding. Tensile, flexure, and impact samples were molded using an injection molder. Test specimens were conditioned for a minimum of 72 hours at 23°C and 50% RH prior to testing. All physical property evaluations were conducted in accordance with appropriate ASTM testing procedures. 

---