High Temperature GPC with a Single Capillary Viscometer

Abstract

Abstract The purpose of this paper is to discuss the results obtained with high temperature GPC using a WATERS GPC 1 SOCV equipped with a single capillary viscometer (SCV) and a differential refractive index detector (DRI) prototype. The reason for using a DRI prototype is that it has been demonstrated that a standard DRI detector may lead, under certain conditions, to erroneous results in viscosity calculations because of the occurrence of a very small flow fluctuation so-called “Lesec effect” when the polymer flows across the detectors (1–3). This very small fluctuation is enough to produce a significant apparent shift of the viscometer peak and leads to a small rotation of the Viscosity law. The consequence is an abnormal small decrease of the Mark-Houwmk a exponent. This phenomenon is caused by the specific Viscosity of the polymer solution increasing the pressure drop in the detector area (1–3).