A Precision Ethylene-Styrene Copolymer with High Styrene Content from Ring-Opening Metathesis Polymerization of 4-Phenylcyclopentene.
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 (H2 -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 H2 -P4PCP are amorphous materials with similar glass transition temperatures (Tg ) 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.
Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, DLC 118, Tallahassee, FL, 32306, USA.
William J
WJ
Neary
Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, DLC 118, Tallahassee, FL, 32306, USA.
Justin G
JG
Kennemur
D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D005030:Ethylenes / Q000737:chemistry*; D015394:Molecular Structure; D058105:Polymerization; D020058:Styrene / Q000737:chemistry*
C000617022:4-phenylcyclopentene; D003517:Cyclopentanes; D005030:Ethylenes; D020058:Styrene; C036216:ethylene
cyclopentenes; polyolefins; polypentenamers; ring-opening metathesis polymerization (ROMP); thermodynamics