Polymer laboratory flammability test

One of the most useful laboratory flammability tests is the oxygen index (Of) test (ASTM D-2043 and ASTM D-2863). In this test, the polymer is burned by a candle in controlled... 

Preparation of Samples for Flammability Testing. Samples of the phosphorus containing terepolymers and of the polymer blends were converted to film by compression molding on a Carver Laboratory Press with electrically heated platens. The films were prepared at 250°C and 20,000 lb. pressure, using a 10 mil thick frame mold. Samples (2" x 1/4") were cut from this film for flammability testing. 

Since many polymeric materials are used as clothing, household items, components of automobiles and aircraft, etc. flammability is an important consideration. Some polymers such as polytetrafluoroethylene and PVC are naturally flame-resistant, but most common polymers such as PE and PP are not. Small-scale horizontal flame tests have been used to estimate the flammability of solid (ASTM D-635), cellular (ASTM D-1692-74), and foamed (ASTM D-1992) polymers, but these tests are useful for comparative purposes only. Large-scale tunnel tests (ASTM E-84) are more accurate, but they are also more expensive to run than ordinary laboratory tests cited before. 

Flammability. The results of small-scale laboratory tests of plastic foams have been recognized as not predictive of their tme behavior in other fire situations (205). Work aimed at developing tests to evaluate the performance of plastic foams in actual fire situations continues. All plastic foams are combustible, some burning more readily than others when exposed to fire. Some additives (131,135), when added in small quantities to the polymer, markedly improve the behavior of the foam in the presence of small fire sources. Plastic foams must be used properly following the manufacturers recommendations and any appHcable regulations. 

Small-scale horizontal flame tests have been used to estimate the flammability of solid (ASTM-D635) and foamed polymers (ASTM-D1992), but these tests are useful for comparative purposes only. Large-scale tunnel tests (ASTM-E84) and corner wall tests are more significant, but they are also more expensive than laboratory tests. 

Flame retardant is a class of materials that when compounded into plastics, provides a specific reaction during combustion. These reactions cause the initially flammable substances to ignite with more difficulty and will inhibit the propagation compared to the original substrate under laboratory test conditions (Frank 2000). Flame retardant is a substance that can be chemically inserted into polymer molecules or physically blended in polymer after polymerization to suppress, reduce or delay the propagation of a flame through plastic materials. Combustion is supported by three critical elements—energy, O, and fuel. For flame retardants to be effective, they must somehow interfere with one or more of those three elements. 

Underwriters Laboratories (UL) provide Standards UL 94 Tests for Flammability of Plastic Materials for Parts in Devices and Appliances. The standard is important for classifying polymeric materials (including polymer blends and alloys) for the use in electrical applications. It is widely used and the results are reported in the literature and in company catalogues. However, the requirements are not applicable to polymeric materials used in building construction or finishing. The tests conducted under this standard are summarized below. 

Autoignition temperature n. The temperature at which a combustible material will ignite and burn spontaneously under specified conditions. Troitzsch J (2004) Plastics flammability handbook principle, regulations, testing and approval. Hanser-Gard-ner Publications, New York. Babrauskas V (2003) Ignition handbook. Fie Science Publishers, New York. Wypych G (ed) (2001) Handbook of solvents. Chemtec Publishing, New York. Tests for comparative flammability of liquids, UI 340. Laboratories Incorporated Underwriters, New York, 1997. Nelson G (1990) Fire and polymers hazards identification and prevention. Oxford University Press, UK. 

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