RHEOLOGICAL CHARACTERISTICS OF PROANTHOCYANIDIN POLYMERS FROM PINUS-RADIATA .1. RHEOLOGICAL BEHAVIOR OF WATER-SOLUBLE EXTRACT FRACTIONS ANDPHLOBAPHENES

The theological characteristics of the solutions of the whole extracts and their fractions from the Pinus radiata bark were investigated. Th e viscosity changes upon addition of aqueous NaOH solution into the so lutions of the hot water extracts are due mainly to the dissolution of the phlobaphene fraction. The polyelectrolyte character was establish ed from the solutions of the hot-water extracts. The kinetics of the s ize growth of naturally forming phlobaphenes could be observed by phot on correlation spectroscopy (PCS) from the solutions of hot-water extr acts. Mild sonication could degrade phlobaphenes partly and this indic ates that the formation of phlobaphenes is partly associated with coll oidal interaction. (C) 1995 John Wiley and Sons, Inc.