Use of the branching theory in approximation of viscosity of the thermoset: Phenol-formaldehyde resin and boron oxide

✍ Scribed by Vadim Sh. Mamleev; Konstantin M. Gibov

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 212 KB
• Volume: 66
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19971010)66:2<319::aid-app12>3.0.co;2-t

✦ Synopsis

The kinetics of step polycondensation is described on the basis of the classical branching theory. A simple method is proposed for calculation of the average longest length (L) of the linear chain in a crosslinked molecule under arbitrary functionalities of original monomers. A viscosity of the system is represented as a product of a structure factor by a friction factor. The latter was taken as the Arrhenius exponent. The structure factor was chosen in the form of a power function of L. The method has been used for the approximation of the viscosity of phenol-formaldehyde resin in the course of curing by boron oxide. An activation energy of 11.8 kcal/mol was found by the method of a best matching of the structure factor for the different viscosity kinetic isotherms in the scale of a reduced time of the reaction.