ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
We have studied the migration of the hindered phenol, octadecyl-3,5-bis (1,1-dimethylethyl)-4-hydroxybenzenepropanoate, and the phosphite co-stabilizer tris 2,4-bis(1,1-dimethylethyl)phenylphosphite, out of films of polypropylene (nominal melt flow 3.5 g/10 min). Loss of additive from an initial 10% weight-% level in the polymer was followed by FTIR bands in the appropriate regions. Temperatures of 298 K, 313 K and 333 K were used. An attempt was made to analyze migration data using Fick's law for diffusion by means of a least squares fit. Octadecyl-3,5-bis (1.1-dim ethylethyl)-4-hydroxybenzenepropanoate diffused according to Fick's law with a temperature independent diffusion constant (D = 1.27 × 10-15 m2 S-1) to a steady state concentration of 7.2 % + -0.56 weight-%. The phosphite did not diffuse at all at 298 K and 313 K, but diffused with D = 8.1 × 10-16 m2 S-1 to a steady level at 333 K. Our interpretation of the phosphite migration data assumes that most of the phosphite in the sample is immobilized. A subset of the total phosphite level is free to diffuse to the surface of the polymer.
Zusätzliches Material:
10 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760312209
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