Viscoelastic Properties of Melts of 'RADEL R' Polysulfone Fractions

The linear viscoelastic properties of a series of RADEL R polyethersulfone fractions have been studied. The molecular weight of the fractions ranged from 2.4 X 103 to 7.2 X 104. The RADEL R polyethersulfone is a thermorheologically complex material. After correction to iso-free volume, it has been found that 1/0∝M3.4,w in agreement with the relation expected for entangled flexible polymers. Below Mw = 10 000, 1/0∝ M2.0 w. From integration under the loss peak of high molecular weight fractions it is found that the plateau modulus G°N=3.6x 107. It is calculated that at 282°C the molecular weight between entanglements is Me=1550. The high plateau modulus is related to the molecular parameters of RADEL R polyethersulfone. Both the Graessley-Edwards model and the Lin model are discussed for a number of polymers that contain phenylene groups in the main chain.