| Methods for the synthesis of diene-functionalized macromonomers in hydrocarbon solution at or near room temperature were developed utilizing anionic polymerization techniques. The resulting functional polymers were characterized by a variety of methods in order to establish their functionality, including 1H and 13C NMR spectroscopy, Attached Proton Test, size exclusion chromatography, MALDI-TOF MS, and thin layer and column chromatography.; Initial investigations of the synthesis of diene-functionalized macromonomers concentrated on the functionalization of polymeric organolithium compounds with 3,4-epoxy-1-butene (EPB). By 13C NMR, it was found that functionalization of poly (styryl)lithium with EPB yielded functional polymer in high yield, but produced three regiochemically different chain ends. A highly regioselective product (1,4-addition) was obtained by the use of either dienyllithium chain ends, addition of triethylamine, inverse addition, or low temperature. The resulting butene-ol functionalized polymer was dehydrated to form the corresponding diene-functionalized macromonomer, but side products were formed which could not be eliminated by alteration of the reaction conditions.; An alternative method for the synthesis of diene-functionalized macromonomers is the use of 1,3,5-hexatriene (HXT) as a functionalizing agent. Since HXT is anionically polymerizable, care must be taken to control the stoichiometry, temperature and reaction time of the functionalization reaction. The functionalization of PSLi with an excess of HXT in toluene at −10°C produced functional polymer by 1H NMR spectroscopy. Upon analysis of the polymer by MALDI-TOF MS, evidence for oligomerization was observed. Oligomerization was eliminated by the use of a small excess of HXT to the chain end and the reaction was run for 15 minutes after monitoring the extent of reaction by UV-vis spectroscopy. The chain end microstructure was determined by modification with maleic anhydride along with 13C NMR spectroscopy. The resulting diene-functionalized macromonomer with reactive end groups (1,6- and 1,2-addition) was obtained in 82 wt % yield as determined by quantitative column chromatography. The remainder of the product contained unfunctionalized polymer and the unreactive 1,4-addition product.; Initial investigations into the reactivity of the resulting diene-functionalized macromonomers were performed by the reaction of the macromonomer with a higher molecular weight PSLi. Analysis by SEC indicated that most of the functionalized polymer was reactive to PSLi, with only a small unreacted portion. |
