Chemistry Reference
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others based upon hindered phenols. They are selected based upon the poly-
mer being stabilized and the desired properties such as color retention and
extraction resistance. For example, AO 1076 and AO 1010 are used in several
polymers including polyolefins, but for nylons AO 1098 is recommended.
H
H
O
O
O
O
C
18
H
37
C
O
O
4
AO 1076
AO 1010
H
O
OH
O
N
H
O
AO 1098
Amine antioxidants are also used. They too are considered to act as
radical scavengers. Commonly these are substituted p-phenylenediamines
or alkylated diphenyl amines. These are used more in rubber or lubricant
formulations and less so in thermoplastics. Often they impart color so they are
more likely to be used in formulations that are pigmented with carbon black.
HN
N
C
8
H
17
C
8
H
17
HN
Amine antioxidants
Another type of antioxidant sacrificially reacts with oxygen, probably in
the form of a peroxide. This type of antioxidant is often called a secondary
antioxidant. Commonly they are used in conjunction with a primary antiox-
idant such as a hindered phenol. They are typically phosphites, which upon
reaction with oxygen become phosphates or sulfides that can react with oxy-
gen to form sulfoxides or sulfones, depending on the degree of oxidation. The
same concerns about polymer compatibility and volatility apply here also.
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