View source for Aging (plastic pipe material)


== Definitions ==

(1) Degradation of a pipe material when exposed to heat for extended period of time.

(2) Physical and chemical changes of plastic material when exposed to heat and humidity.

(3) The durability of plastics may be limited by either chemical or physical aging.

Chemical aging refers to the loss of performance properties caused by gradual breakdown of polymer molecules into smaller units.

Physical aging is the result of gradual adverse change in the physical state and order of a plastic. For a plastic to be durable it must resist both forms of aging under the anticipated service conditions.

All polymers can be chemically degraded by the application of sufficient heat, radiation such as ultra-violet (UV) segments in sunlight.


== References ==
1. ASTM D3045 - 92(2010) Standard Practice for Heat Aging of Plastics Without Load

2. ASTM D7444 - 11 Standard Practice for Heat and Humidity Aging of Oxidatively Degradable Plastics

3. Buried Plastic Pipe Technology, Issue 1093 by George S. Buczala