Methods for removing the residual Grubbs' third generation catalyst from polymers prepared by ring opening metathesis polymerization are reported. Two strategies were investigated for reduction of the residual catalyst in the final polymer product. The first strategy involved the use of heterogeneous functionalized particles to scavenge the catalyst from the solution. Filtration of the particles followed by precipitation produced polymers with 10-60 ppm residual catalyst, depending on the type of particle used, surface functional groups, and number of equivalents. The second strategy used small organic molecules that could coordinate to the metal species and modify the solubility of the catalyst, facilitating partitioning of the catalyst into the precipitation solvent. Several types of molecules with varied functionality reduced the residual catalyst level to 30-120 ppm, depending on the loading. Hydrogenation of the polymer backbone followed by precipitation lowered the residual Ru content from 195 ppm to 10 ppm, suggesting that the difficulty of completely removing the catalyst could be a result of coordination of the metal species to the double bonds in the polymer backbone. Reducing the amount of trace catalyst significantly improved the oxidative stability of the polymer. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5752-5757, 2010

Diol-functionalized trisaminocyclopropenium (TACP) carbocations were used as chain extenders in a twostep synthesis of a segmented polyurethane. Differential scanning calorimetry demonstrated significant differences in the crystallization behavior of the poly(tetramethylene oxide) soft segment when minor changes were made to the TACP structure and when compared to a control that was chain extended with butane diol. Fourier transform infrared spectroscopy was used to characterize the different level of hydrogen bonding in the polymers and showed that the bulky, charged TACP chain extender limited hydrogen bonding interactions when compared to the control. Dynamic mechanical analysis was used to probe the thermomechanical behavior of polymers that showed that the TACPcontaining polymers were much more resistant to flow at high temperatures when compared to the control. Small-angle X-ray scattering showed a phase separated morphology for all the polymers tested. Tensile testing of the TACP polyurethanes demonstrated an elastic response over a wide range of strain, followed by a significant strain hardening. These results suggest a morphology of ionic aggregates rather than hard segment physical cross-links.

We present a detailed investigation of the aminolysis of six‐membered cyclic carbonates to form (poly)hydroxyurethanes. Model reactions between hexyl amine and trimethylene carbonate were performed under different conditions where we surveyed the effects of temperature and the presence of catalyst on the rate of reaction. Increased temperatures and the presence of catalyst lead to significant increases in the rate of reaction and overall conversion depending on the structure of the catalyst. Similar observations were also made in model polymerization between a carbonate derivative of di(trimethylolpropane) and diaminopentane. However, the increased rates of reaction and conversion only lead to modest gains in molecular weight. In addition, gelation of the polymerization mixture often occurred as well. Nominal and high‐resolution mass spectrometry were used to identify side products that formed during the reaction between trimethylene carbonate and hexyl amine, which explained the gelation of polymerization mixture and lower than expected molecular weights. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44941.

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