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Kinetics of polycondensation of urea with formaldehyde. Molecular weight distribution, average molecular weight, and polydispersity parameters
Author(s) -
Katuščák S.,
Tomáš M.,
Schiessl O.
Publication year - 1981
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1981.070260201
Subject(s) - dispersity , condensation polymer , molar mass distribution , formaldehyde , urea , chemistry , urea formaldehyde , polymer chemistry , titration , organic chemistry , polymer , adhesive , layer (electronics)
The molecular weight distribution, molecular weight averages M n , M w , M z , polydisperisty coefficient, statistic standard deviation of number and weight distribution, and Hoseman–Schramek index of the polycondensates of urea with formaldehyde have been estimated. The properties of this solution were obtained by the help of the combination of the following methods: GPC, VPO, turbidimetric titration, and fractional precipitation. The course of the polycondensation described was formally divided in the following stages: (1) formation of methylolated urea derivates and of the lowest oligomers, (2) decrease in the content of methylol urea and in the content of the lowest oligomers with M < 200, and production of soluble molecules between 10 3 and 10 4 , and (3) formation of insoluble products.