Poly(p-phenylene alkylene)s – A forgotten class of polymers

Abstract

Within the wealth of hydrocarbon polymers, poly(p‐phenylene alkylene)s (“alkarotics”) hold a special position since they have been a long forgotten class of hydrophobic polymers. This is somewhat surprising, since the cornerstones of this polymer family cover extremely broad materials properties and the few known representatives attract attention with very favorable characteristics. In the course of this article, four new representatives of this family are presented. Whereas poly(p‐phenylene octylene) (PPPO; 90°C), poly(p‐phenylene hexylene) (PPPH; 120°C) and poly(p‐phenylene propylene) (PPPPr; 110–130°C) have surprisingly low melting temperatures, the highly crystalline poly(p‐phenylene butylene) (PPPB), melting between 200 and 225°C, meets many of the requirements that are essential for a novel, hydrophobic, processable, engineering polymer. In connection with the efforts to tailor the melting temperature of these polymers, a simple, semi‐empirical methodology to estimate melting temperatures of unknown representatives of homologous series of polymers was developed and verified. By means of this approach, the melting temperatures of PPPH and PPPB could be predicted with remarkable accuracy. In addition, it was shown that the method is not restricted to the present alkarotic polymers, but it seems to have a rather broad range of applications as shown by the successful description of the polymer series, including various liquid‐crystalline hydrocarbon polymers and different polyamides.

Synthesis of poly(sulfonate ester)s by ADMET polymerization

“…18,19 Unlike the related ring-opening metathesis polymerization (ROMP), which is a chain-growth process driven by the release of ring strain, ADMET is driven by the removal of the ethylene gas generated as a by-product. ADMET chemistry has been used recently in the synthesis of both all-carbon polyolefins [20][21][22] as well as polyethylene-like polymers containing heteroatoms [23][24][25][26][27][28][29] or aromatic rings [30][31][32] in the main chain. ADMET offers an interesting alternative for the incorporation of aliphatic sulfonate esters into the polymer backbone, which are rare in the literature.…”

The ADIMET Reaction: Synthesis and Properties of Poly(dialkyl para phenyleneethynylene)s

“…PPEs should be uniquely suited for this purpose because catalytic hydrogenation of their triple bonds should lead to a coiled polymer with only a slightly increased molecular weight. The hydrogenated PPE would be an isomeric polystyrene 60 [39], in which the polymer connection is made through the 1,4-positions of the benzene ring instead of the benzene units substituting a polyethylene chain. The polymer 60 is expected to be coiled and thus better amenable to reliable molecular weight determination by GPC using polystyrene standards.…”

Poly(p-phenylene butylene): A New, Processable, High-Melting Hydrophobic Polymer

“…22 It is noteworthy that the PPPB produced here has a dramatically different melting behavior than the material that was obtained by Brown and Farthing, 21 for which we do not have a plausible explanation; other than that, these authors may not have produced PPPB.…”