In:
Die Makromolekulare Chemie, Wiley, Vol. 189, No. 7 ( 1988-07), p. 1719-1737
Abstract:
13 C NMR analysis of carbamates and substituted ureas as model compounds, derived from 5‐isocyanato‐1,3,3‐trimethylcyclohexylmethyl isocyanate (isophorone diisocyanate) (3), allowed the quantitative determination of global conversions of hydroxyl and NCO groups. The individual conversions of the two NCO groups, as observed in the polycondensations of 2,2′‐methylimino‐ and 2,2′‐dodecyliminodiethanol (1a and 1b) with 3 in toluene, were examined. The primary NCO group of 3 was found to be two times more reactive than the secondary one. The global kinetics of the polycondensations followed the 2nd and 3rd order for conversions lower than 50%. Beyond 50% of conversion, zero order kinetics were observed because of the decrease of the rate due to the steric hindrance of both cyclohexyl and alkyl residues. Alkyl radical length in 1 and hydroxyl auto‐association equilibria were found to have the same effect on polycondensation as on condensation.
Type of Medium:
Online Resource
ISSN:
0025-116X
,
0025-116X
DOI:
10.1002/macp.02.v189:7
DOI:
10.1002/macp.1988.021890725
Language:
English
Publisher:
Wiley
Publication Date:
1988
detail.hit.zdb_id:
1475026-0
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