On the flexibility of cyclochain polymers

Abstract

Conformational parameters for a wide variety of aromatic cyclochain polymers have been computed assuming free rotation about virtual bonds. The flexibility with free rotation is shown to be determined by the geometry of the repeat unit and can vary over a wide range (15–1500 Å). Experimental values of the Kuhn segment length A are calculated from literature data on the hydrodynamic behavior of polymeric macromolecules of this class in solution. For most polymers Afr for free rotation is equal to the experimental Aexp, and hindered rotation is mainly due to bulky substituents. © 1993 John Wiley & Sons, Inc.

Influence of chemical structure on glass transition temperature of polyimides

“…An exception is made by the point belonging to polymer 1: this is out of that dependence. The rigid connection between two imide rings, and (11)(12)(13)(14)(15)(16) the structure of the diamine component determine a high conformational rigidity (A fr = 37 Å ) of this polymer and, consequently, a high glass transition temperature. In the last three groups of polymers containing various bridges between imide rings, such as carbonyl, hexafluoroisopropylidene or tetramethylsiloxane, which increase the flexibility of polymers, the change of diamine component has a significant influence (Table 3; Figs.…”

“…The first group of polymers (1)(2)(3)(4)(5): polyimides based on isopropylidene-bis(aniline) or hexafluoroisopropylidene-bis(aniline) [20] The third group of polymers (11)(12)(13)(14)(15)(16): polyimides based on bis(aminophenoxy-phenyl)-isopropane or bis(aminophenoxy-phenyl)-hexafluoroisopropane [20] Struct Chem (2010) 21:1013-1020 1015 not find any data regarding its synthesis and glass transition temperature. The dependence of glass transition temperature on conformational rigidity for the other three polymers in this group is linear with a high correlation coefficient (R = 95.57%).…”

Occupied and Accessible Volumes in Glassy Polymers and Their Relationship with Gas Permeation Parameters

“…The structures of the polyimides studied as well as their densities, r, and Kuhn segments, A fr , [17][18][19] are given in [17] according to Equation (7):…”

Structural aspects in polymers: interconnections between conformational parameters of the polymers with their physical properties

“…It is known that the value of the Kuhn segment in polyheteroarylenes varies from 10 to 15 Å to infinity depending on the monomer structure of the polymer and, calculated under the assumption of free rotation, is close to the experimental value [4] (Table 1). As can be seen from Table 1, the rotation retardation parameter r = A exp /A fr is rather small.…”