A series of aromatic polyethersulfones based on biphenol and dichlorodi phenylsulfone have been prepared and fractionated. The fractions have been character ized by light scattering and intrinsic viscosity measurements. The characteristic ratio C ∝ = 1.96 which is in agreement with the freely rotating nature of the polyethersulfone chain. The molecular weight dependence of the glass transition temperature is established. The low temperature β-transition is at -113°C when measured at 1 rad/s with a mechanical spectrometer.
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 10 3 to 7.2 X 10 4 . The RADEL R polyethersulfone is a thermorheologically complex material. After correction to iso-free volume, it has been found that 1/0∝M 3.4, w in agreement with the relation expected for entangled flexible polymers. Below M w = 10 000, 1/0∝ M 2.0 w . From integration under the loss peak of high molecular weight fractions it is found that the plateau modulus G° N =3.6x 10 7 . It is calculated that at 282°C the molecular weight between entanglements is M e =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.
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