Degradation of ABS
Degradation of ABS
(OP)
I'm dealing with an ABS part that has lost significant tensile strength over time. The parts have been stored in plastic bags (not hermetically sealed), which are stored in cartons. The parts have been stored for around 2 years in a warehouse, where the temperature is generally controlled. Since the parts are not exposed to UV light, what would be the source(s) of degradation in the confined environment?
Thanks in advance.
Thanks in advance.





RE: Degradation of ABS
RE: Degradation of ABS
No analytical work has been done. We could run FTIR, but what specifically would we be looking for? I presume we'd need a control or baseline.
RE: Degradation of ABS
Yes you would need a baseline or control sample to compare against the suspect sample using FTIR. This may be able to detect whether or not the ABS has been contaminated, has been exposed to a solvent or other chemical prior to packaging, etc.
Check out the following links for more information on Environmental Stress Cracking (ESC):
http://www.immnet.com/articles?article=401
ht
Michael Sepe's column The Materials Analyst in Injection Molding Magazine is probably the best single resource I have ever seen with respect to failure analysis of polymer components. He illustrates the various analytical methods like FTIR, DSC, TGA, etc., and shows how to use them to solve problems such as this. Molded-in stresses may be sufficient in the presence of a chemical to cause ESC of ABS. THe following link will allow you to search the archives of IMM:
http://www.immnet.com/search
enter Environmental Stress Cracking
or residual stress
or ABS
RE: Degradation of ABS
RE: Degradation of ABS
RE: Degradation of ABS
There has been some discussion how to study shelf-life of these items in the warehouse. The proposal is to accelerate aging with UV exposure or temperature. My understanding is the degradation mechanism in UV exposure is different than that of oxidation, as you mentioned above. Would you agree? Does temperature accelerate oxidiation, or is another degradation mechanism involved there, too?
RE: Degradation of ABS
It's a bit of a science project, but you ideally need to run life test at two different temperatures. The relative acceleration of failures between those temperature allows you to determine the activation energy. You can then use that energy to calculate the room temperature life based on accelerated temperature testing.
TTFN
RE: Degradation of ABS
RE: Degradation of ABS
RE: Degradation of ABS
Ambient is controlled in the warehouse, between 65F-75F. Regarding the material, we know the manufacturers material designation.
RE: Degradation of ABS
RE: Degradation of ABS