Unveiling the hyperbolic thermal behaviour of poly(p-phenylene alkylene)s

Abstract

A series of poly(p-phenylene alkylene)s with methylene run lengths ranging from 8 to 40 were obtained by ADMET polymerization of symmetrical α,ω-diene monomers and subsequent exhaustive hydrogenation.

Synthesis and Thermal Characterization of Precision Poly(p‐cyclohexylene alkylene)s via Acyclic Diene Metathesis Polycondensation

“…In order to isolate the effect of 1,4‐cyclohexylene units on the melting behavior of cycloaliphatic polymers, we compared the melting temperatures of PPC with the corresponding data for poly( p ‐phenylene alkylene)s (PPPs) reported by Sauty et al PPC‐ X and PPP‐ X share the same carbon skeleton and differ only in the saturation state of the six‐membered rings along the polymer chain (aromatic 1,4‐phenylene in PPP; and fully saturated 1,4‐cyclohexylene in PPC). As shown by Sauty et al, intermolecular interactions between the aromatic rings in PPP can be neglected if the methylene chain is longer than eight units ( X > 8) . Therefore, changes in the thermal behavior of PPC and PPP considered in this work can be attributed to the structural differences among the rings.…”

“…It is important to note that the higher melting points exhibited by PPC are observed only if the methylene chain is sufficiently long to inhibit the intermolecular interactions between aromatic rings. In fact, the melting points of poly( p ‐phenylene alkylene)s become higher than the corresponding poly( p ‐cyclohexylene alkylene)s in cases where the additional stabilization due to the aromatic ring stacking cannot be neglected …”

“…Onset temperature of thermal degradation T D (temperature where 5% mass loss occurs) of PPC‐ X and PPP‐ X where X indicates number of methylene units between the aliphatic and aromatic rings, respectively. T D (PPP) obtained from Sauty et al…”

Synthesis of poly(phenylene methylenes) via a AlCl3‐mediated Friedel–Craft alkylation of multi‐substituted benzyl bromide with benzene

“…Poly(phenylene alkylene)s (PPAs), well defined as multifunctional hydrocarbon polymers and also categorized as precision polymers, are made of alternating phenyl (rigid segment) and alkylene (flexible segment). Due to the extraordinary stabilities in structure, thermo, and mechanics, parylene N, namely poly( p ‐xylylene) (PPX), is the only polymer of this series utilized in industrial applications .…”

A review of how to do an acyclic diene metathesis reaction

“…Hence, high conversion of monomer is required in order to achieve high molecular weight in ADMET polymerization, and the PDI of ADMET polymers is theoretically 2.0, which is typical of that for any step‐growth polymerization. Under optimized reaction conditions, the number‐average molecular weight of an ADMET polymer can reach up to 80 000 g mol −1 , which is sufficient for performance studies.…”