ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Antioxidant efficiency versus structure was investigated using rate of carbonyl formation at 110 and 170°C of a 20 mil plaque of polyethylene containing 0.01 weight % additive. This study indicates that the following are important in phenolic and amine antioxidants: 1The number of H. atoms available: Antioxidant efficiency is increased by adding a second hydroxyl group as well as by introducing a methylene bridge.2The number and location of substituents: Alkyl substitution of the phenolic ring is an important factor in stabilization. Groups which decrease the strength of the NH bond increase the effectiveness of amine antioxidants.3Solubility: The less compatible the antioxidant, the poorer its stabilizing action.4Volatility: Many stabilizers are ineffective at high temperature because of volatilization.5Bridge between rings: A sulfide bridge can be equivalently substituted for a methylene bridge.6The need for stabilization of the radical formed after removal of H: This stabilization could occur via; Hydrogen bonded chelates, resonance and steric hindrance.
Additional Material:
12 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760020314
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