Ring Opening Metathesis Polymerization Review

Ring Opening Metathesis Polymerization Review-89
Alkyl chain transfer is also possible, where the active end is quenched by transferring an alkyl chain to another polymer.The mechanism for ROMP follows similar pathways as olefin metathesis.Examples of cyclic monomers that polymerize through this mechanism include lactones, lactams, amines, and ethers.

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Liquid crystalline polymers (LCPs) have gained attention as materials with interesting optical, mechanical and rheological properties.

This review summarizes research on thermotropic liquid crystalline polymers synthesized by metathesis polymerization techniques.

Ring-opening of cyclic monomers is often driven by the relief of bond-angle strain.

Thus, as is the case for other types of polymerization, the enthalpy change in ring-opening is negative.

The mesophase type and the thermal transition temperatures are influenced not only by the attached mesogenic moiety but also by the stiffness of the polymer backbone, the spacer lengths between the main chain and the liquid crystalline entity, the isomerism, the tacticity, and so on.

In addition, the use of acyclic diene metathesis polymerization (ADMET) or alternating diene metathesis polycondensation (ALTMET) offer new possibilities for creating new main chain liquid crystalline polymers (MCLCPs).

For example, if the atom bearing the positive charge is stabilized by electron-donating groups, polymerization will proceed by the S When the amount of monomers becomes depleted, termination can occur intra or intermolecularly.

The active end can "backbite" the chain, forming a macrocycle.

Following Flory–Huggins solution theory that the reactivity of an active center, located at a macromolecule of a sufficiently long macromolecular chain, does not depend on its degree of polymerization (DPi), and taking in to account that ΔG, for polymerization in the bulk, are well above or below the operable polymerization temperatures, respectively.

The polymerization of a majority of monomers is accompanied by an entropy decrease, due mostly to the loss in the translational degrees of freedom.

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