The Many Faces of Buna N (Nitrile)
The Many Faces of Buna N (Nitrile)
(OP)
I have been searching for a specification for Buna N that will insure me that the material does not grow in Jet Fuel.
I've ordered the stuff in about 4 different specs and some batches grow and others do not. The suppliers keep telling me that it is the same material... however, obviously the elastomer industry does not have a handle on their processes.
Is there any specification that I could buy this material to, that will give me consistent material props. ?
I've ordered the stuff in about 4 different specs and some batches grow and others do not. The suppliers keep telling me that it is the same material... however, obviously the elastomer industry does not have a handle on their processes.
Is there any specification that I could buy this material to, that will give me consistent material props. ?





RE: The Many Faces of Buna N (Nitrile)
With regards to specification, I suggest the following:
1. Start with applicable aerospace standards like SAE AMS 3212, 3213, 3214, 3215, or 3224. These standards specify fuel-resistant NBR in various durometers.
If you have already done this, and still have excessive variation, then you should
2. Exactly specify the requirements using ASTM D 471 Standard Test Method for Rubber Property-Effect of Liquids. In this standard, you specify the temperature range (85 + 2 C, 100 + 2 C, etc.), the duration (22, 46, 70, 166, 670, 1006, 2998, or 4990 hours), the fluid (standard fuels ranging from 100% isooctane to 100% toluene, or your specific grade), and the acceptance criteria (minimum and maximum change in mass and/or volume-- see sections 9-14).
RE: The Many Faces of Buna N (Nitrile)
Would it be a safe assumption that if I were to order the NBR with a higher Shore A that it would contain more acrylonitrile?
The properties are essentially a non issue since the rubber is being used as a seal for shipping purposes. (mostly room temp and disposable)
RE: The Many Faces of Buna N (Nitrile)