Precision Polyelectrolytes with Phenylsulfonic Acid Branches at Every Five Carbons

Abstract

A precision polyethylene containing phenyl branches at every fifth carbon (p5Ph) is nearly quantitatively functionalized (≈95%) with sulfonic acid groups on the para-position of each phenyl branch (p5PhS-H). Unlike polystyrene sulfonate (PSS), p5PhS-H has a glass transition temperature (T_g = 109 °C) well below its thermal decomposition temperature (T_d ≈ 200 °C), making this new material capable of thermal processing into molds and films at temperatures between these thermal limits. Neutralization of the sulfonic acid groups with varying counter cations (Li⁺ , Na⁺ , Cs⁺ ) produces a new class of precision polyelectrolytes. Neutralization and increasing size of the counter cation improves the thermal decomposition temperature (T_d ) to over 400 °C for the Cs⁺ form. Neutralization causes T_g to increase above T_d for the Li⁺ and Na⁺ form. The Cs⁺ form is found to have an accessible T_g = 294 °C. Further investigations of water absorption and the polyelectrolyte effect of these systems are discussed.

Keywords: dry properties; polyelectrolytes; precision polyolefins.