Project Details Terminology of polymers with ionizable groups and polymers containing ions

Project No.:
2000-006-1-400
Start Date:
01 January 2000
End Date:
25 October 2006
Division Name:
Polymer Division
Division No.:
400

Objective

To prepare definitions of terms related to general class of ion-containing polymers i.e. polymers containing ionic or ionizable groups within a macromolecule as well as polymeric systems composed of non-ionic macromolecules and ionic admixtures. The present lack of clarity of terminology in the field results in confusion and difficulties in proper scientific and technological understanding.

Description

Properties of several polymeric materials are related to the presence of ionic groups being either an inherent fragments of polymer molecules or present in low molecular weight components of composite polymeric materials. Ionic polymers contain both covalent and ionic bonds which together form a chain or network structure. In majority of cases the covalent bonds form the chain and ionic bonds are additional to this structure modifying its properties. The presence of both ionic and covalent bonds makes the ionic polymers a very diverse group of materials and their physical properties can vary from soft, pliable thermoplastic materials (e.g. ionomers) via rubbery elastomers reversibly cross-linked by ionic bonds or ionic aggregates to rigid, highly cross-linked materials (e.g. ion-exchange resins). Polymers with high content of ionic (or ionizable) groups are water soluble and are classified as polyelectrolytes. In principle any macromolecular structure can be transformed into polyelectrolyte by covalently attaching sufficient number of ionic groups to a polymer backbone. The importance of this class of ionic polymers stems from their widespread application in many areas of everyday life and industrial production as well as the close affiliation of polyelectrolytes with the processes of living matter (some essential biopolymers, like nucleic acids and proteins, are polyelectrolytes).

The presence of ionic (or ionizable) groups in polymers may affect also other properties (e.g. electrical properties) of resulting materials. Incorporation of ionic groups (by process known as doping) into polymers containing sequences of coniugated multiple bonds (e.g. polyacetylene) leads to the increase of the conductivity to the level which is of practical interest. The electric conductivity may also be imposed by blending the conducting low molecular weight material (frequently ionic) into non-conducting polymer matrix. These two groups of systems are structurally different which is not always reflected in commonly used terminology. The aim of the project is to formulate clear concepts and definition of terms related to the structure and properties of polymeric materials containing ionic or ionizable groups.

Progress

A manuscript has been prepared for publication in Pure Appl.Chem. A final document was submitted to public reviewcomments until 31 May 2005. > seeprovisional recommendations

Project completed – IUPAC Recommendations published in PureAppl. Chem.78(11), 2067-2074, 2006.

<project announcement published inChem.Int.22(5) 2000>