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Effect of stearate processing aids upon polypropylene stability
Author(s) -
Russell C. A.
Publication year - 1965
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760050204
Subject(s) - stearate , calcium stearate , polypropylene , materials science , polymer , chemical engineering , copper , polymer chemistry , composite material , organic chemistry , chemistry , metallurgy , raw material , engineering
Fatty acid salts are often added to polymers as processing aids. Although calcium stearate promoted highly reduced mixing torque requirements in polypropylene compositions, this was due largely to lowering of the polymer molecular weight. However, the amount of shear withstood without severe degradation was less. The effects of calcium stearate upon polypropylene stabilization systems were investigated by oxygen absorption studies Up to 50% stabilization was lost, particularly with metals such as copper, with 0.1% calcium stearate even in compositions protected by inhibitors. The stearate evidently reacts with transition metals or their oxides, particularly if acidic materials are present, to give metallic stearates which are extremely effective polyofin oxidation catalysts. Considering these results, the use of stearate processing aids should be avoided if property retention and stability are important in the fabricated article.