Viscoelastic Properties of Melts of 'RADEL R' Polysulfone Fractions

Abstract

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.

Melt‐state polymer chain dimensions as a function of temperature

“…Nonetheless, many 34,35,37 -condition-based chain dimensions illustrate that useful rheological approximations are feasible. It was shown previously 5 that M e could be expressed as follows:…”

Synthesis of High Molecular Weight Polyetherethersulfone‐Allyl Copolymers of Controlled Glass Transition

“…Polymers with molecular weights which are too low (typically lower than twice the molar mass between entanglements M e for a thermoplastic polymer) result in a lack of film‐forming capabilities, or in extremely brittle films and membranes . For aromatic polyethersulfones, published M e values are in the 1550 to 2300 g mol −1 range …”

“…[ 12 ] For aromatic polyethersulfones, published M e values are in the 1550 to 2300 g mol −1 range. [ 26,27 ] Higher molecular weights also increase mechanical resistance. On the other hand, molecular weights which are too high have been shown to lead to higher strength membranes with lower membrane porosity and water fl ux, [ 28 ] larger pore sizes at the surface, [ 29 ] higher permeability, and lower selectivity.…”

“…For instance, selectivity to given chemical classes in filtration or ultrafiltration membranes could be tailored by using appropriate grafted molecules. Sulfonated chains could also be grafted onto the double bond for some fuel cell applications which require higher T g polymers, and for which polyethersulfones sulfonated on the aromatic ring, have been widely studied …”

“…Sulfonated chains could also be grafted onto the double bond for some fuel cell applications which require higher T g polymers, and for which polyethersulfones sulfonated on the aromatic ring, have been widely studied. [18][19][20][21][22][23][24][25][26][27] In the present work, the nucleophilic substitution polycondensation reaction was used to obtain high molecular weight PEES with double bonds inserted along the polymer chain backbone, which are amenable to postfunctionalization reactions. Random copolymers were prepared with the aim of controlling the glass transition temperature and ratio of grafted chains.…”