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A Precision Ethylene‐Styrene Copolymer with High Styrene Content from Ring‐Opening Metathesis Polymerization of 4‐Phenylcyclopentene
Author(s) -
Neary William J.,
Kennemur Justin G.
Publication year - 2016
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201600121
Subject(s) - copolymer , polymerization , styrene , molar mass , materials science , polymer chemistry , differential scanning calorimetry , dispersity , caprolactam , ethylene , glass transition , enthalpy , metathesis , polymer , catalysis , chemistry , organic chemistry , composite material , thermodynamics , physics
Ring‐opening metathesis polymerization of 4‐phenylcyclopentene is investigated for the first time under various conditions. Thermodynamic analysis reveals a polymerization enthalpy and entropy sufficient for high molar mass and conversions at lower temperatures. In one example, neat polymerization using Hoveyda–Grubbs second generation catalyst at −15 °C yields 81% conversion to poly(4‐phenylcyclopentene) (P4PCP) with a number average molar mass of 151 kg mol −1 and dispersity of 1.77. Quantitative homogeneous hydrogenation of P4PCP results in a precision ethylene‐styrene copolymer (H 2 ‐P4PCP) with a phenyl branch at every fifth carbon along the backbone. This equates to a perfectly alternating trimethylene‐styrene sequence with 71.2% w/w styrene content that is inaccessible through molecular catalyst copolymerization strategies. Differential scanning calorimetry confirms P4PCP and H 2 ‐P4PCP are amorphous materials with similar glass transition temperatures ( T g ) of 17 ± 2 °C. Both materials present well‐defined styrenic analogs for application in specialty materials or composites where lower softening temperatures may be desired.