Ring-Opening Metathesis Polymerization

ROMP is initiated by transition metal compounds (typically of Ti, Ta, W, Mo, or Ru), and operates on cyclic or polycyclic olefins, opening the ring and retaining the unsaturation. Two pioneers of ROMP, Richard Schrock and Robert Grubbs, shared the 2005 Nobel Prize in Chemistry for their invention of soluble, well-defined Mo and Ru complexes which allowed for living polymerizations and the synthesis of polymers of well-defined architectures. A representative ROMP synthesis of a diblock copolymer of ethylidene norbornene and cyclopentene using a Mo-based (“Schrock”) initiator, followed by catalytic hydrogenation, is shown below. Note that hydrogenation of polycyclopentene yields perfectly linear, narrow-distribution polyethylene.

Synthetic scheme and GPC traces (bottom left) for an hPEN/hPCP diblock. Top: ethylidene norbornene (EN) polymerization to essential completion (dashed black GPC trace). Right: step 1: cyclopentene (CP) polymerization; step 2: termination at targeted CP conversion by propionaldehyde to yield PEN/PCP diblock (pink GPC trace). Bottom right: hydrogenation over Pd-on-CaCO3 catalyst proceeds without any backbone rearrangements, to yield final hPEN/hPCP diblock (Trzaska et al., Macromolecules, 33, 9215 (2000)).


Supported by the National Science Foundation, Polymers Program, and by Promerus LLC and the Princeton University Innovation Fund for Industrial Collaborations

Current/Recent Group Members Employing ROMP, and Their Project Titles:

Will Mulhearn PhD *18 – “Melt-Miscibility in Block Copolymers Containing Polyethylene”
Adam Burns PhD *17 – “Thermoplastic Elastomers with Composite Crystalline-Glassy Hard Domains via Crystallization from a Single-Phase Melt”
Dong-Gyun Kim PDRA – “Novel Block Copolymers for Butanol Pervaporation Membranes”
Sheng Li PhD *13 – “Structure and Properties of Novel Homopolymers and Block Copolymers Synthesized by Ring-Opening Metathesis Polymerization or Chain Shuttling Polymerization”
John Bishop PhD *11 – “Structure-Property Relationships in Novel Polymers and Block Copolymers from Ring-Opening Metathesis Polymerization”
Michael Showak ‘13 – “Semicrystalline Structure in Hydrogenated Norbornene-Methylnorbornene Statistical Copolymers”
Andrew Stella ‘13 – “Crystal Phase Transitions in Hydrogenated Norbornene-Hexylnorbornene Copolymers”

Selected Recent Publications:

M.T. Showak, A.B. Burns, A.J. Stella, and R.A. Register, "Counit Inclusion in Hydrogenated Polynorbornene Copolymer Crystals", Macromolecules, 46, 9288-9295 (2013).

S. Li, A.B. Burns, R.A. Register, and A. Bell, "Poly(phenylnorbornene) from Ring-Opening Metathesis and Its Hydrogenated Derivatives", Macromol. Chem. Phys., 213, 2027-2033 (2012).

S. Li, S.B. Myers, and R.A. Register, "Solid-State Structure and Crystallization in Double-Crystalline Diblock Copolymers of Linear Polyethylene and Hydrogenated Polynorbornene", Macromolecules, 44, 8835-8844 (2011) [cover article].

J.P. Bishop and R.A. Register, "The Crystal-Crystal Transition in Hydrogenated Ring-Opened Polynorbornenes: Tacticity, Crystal Thickening, and Alignment", J. Polym. Sci. B: Polym. Phys., 49, 68-79 (2011).