ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Depolymerization of poly-∊-caprolactam chips was carried out at low pressures (3-15 mm Hg) and elevated temperature (225°-270°C) in the presence of sodium hydroxide as catalyst. The effects of variation of amount of sodium hydroxide, time, temperature, and pressure on ∊-caprolactam yield were studied. With increase in alkali content the yield increases linearly, reaching a maximum at 1% (w/w) NaOH and then falls. The yield increases with time of depolymerization up to 4 1/2 hr and then becomes practically constant. Between 240° and 250°C there is a sudden increase in depolymerization rate. Further increase in temperature has very little effect. Decrease in pressure from 15 to 3 mm Hg shows a nine-fold increase in yield. The optimum conditions for the depolymerization were a temperature of 250°C, a pressure of 3 mm Hg, and a time 4 1/2 hr in the presence of 1% NaOH (w/w), which gave a 90.5% yield of ∊-caprolactam. Physical properties, IR spectra, and behavior toward polymerization of the recovered monomer indicated the presence of some impurities.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1978.070220205
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