The Preparation of Functionalized Polymers by Ring-Opening Metathesis Polymerization

Citation

Hillmyer, Marc Andrew (1995) The Preparation of Functionalized Polymers by Ring-Opening Metathesis Polymerization. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/W85R-KV31. https://resolver.caltech.edu/CaltechETD:etd-10092007-111841

Abstract

The preparation of polymers that contain functional groups either along the backbone, as side chains, or at the chain ends by ring-opening metathesis polymerization (ROMP) was investigated.

In Chapter 1, the recently developed aqueous ROMP was exploited in the synthesis of a polymer with pendant imide groups. The polymerization of exo-N-methyl-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide was accomplished in aqueous solution under mild conditions using the simple ruthenium(II) coordination complex Ru^IIH₂O₆tos₂ (tos=p-toluenesulfonate). The resultant high molecular weight polymer was isolated in high yield, exhibited a T_g of 225°C, and was thermally stable up to 402°C. Hydrogenation of the polymer yielded its saturated analog which exhibited a lower T_g (170°C) but a higher temperature of decomposition 430°C. Requirements for successful polymerization were investigated.

In Chapter 2, the ROMP of a variety of 5-substituted cyclooctenes by the well-defined metathesis catalyst (PCy₃)₂(Cl)₂RuCHCHCPh₂ (1) was accomplished. The polymers were obtained in moderate to good yields. The structures of the polymers were investigated by IR, ¹H NMR, and ¹³C NMR spectroscopies. The molecular weight of one of the derivatives was controlled by varying the monomer to catalyst ratio and by the addition of a chain transfer agent to the polymerization solution. The thermal properties of the polymers are reported.

In Chapter 3, the ring-opening metathesis polymerization (ROMP) of cyclooctadiene (COD) by three well-defined metathesis catalysts in the presence of a variety of chain transfer agents (CTAs) is described. Expressions for the theoretical molecular weight and functionality were derived for this type of ROMP system. Hydroxytelechelic polybutadienes (HTPBDs) synthesized contained one type of regiochemistry in the repeat unit (1,4) and one type of alcoholic endgroup. The molecular weight of the HTPBDs was controlled by the ratio of COD to CTA and number average functionalities that approached 2.0 were obtained at high CTA to catalyst ratios.

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