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Hydroxyl-terminated telechelic polydiene stars
Abstract
Organolithium reagents containing primary carbanionic center substituted with hydroxyl-carrying mixed acetals (i.e., $\alpha$-butoxyethyl ether, $\alpha$-isobutoxyethyl ether, $\alpha$-isooctoxyethyl ether) have been prepared in high yields. The synthesis for the precursors and the synthesis of the organolithium reagent without any side products has been developed. Solubilities of these initiators in various hydrocarbon solvents has been tested. All the initiators were soluble in benzene but partially soluble in hexane. Various strategies have been devised to synthesize polymers with high 1,4 chain units and narrow molecular weight distribution. Anionic polymerization of butadiene or isoprene using hydroxyl-blocked functional anionic initiators was achieved. The living polydienyllithium or polyisoprenyllithium was coupled with chlorosilanes to give 2-, 3-, or 4-armed material. Any uncoupled material was fractionated from the coupled material. The acetal moiety was hydrolyzed to give hydroxyl terminated telechelic polymers. The polymers have been characterized with regard to end group, quantitative functionalities, molecular weights, molecular weight distribution and microstructures. This thesis also describes the synthesis of hydroxyl-blocked functional anionic initiator containing a secondary carbanionic center. This initiator proved to be hexane soluble. Butadiene was polymerized in hexane using the hydroxyl-blocked secondary anionic initiator to obtain polymers with high 1,4 chain units and narrow molecular weight distributions.
Subject Area
Organic chemistry|Polymers
Recommended Citation
Pyati, Meera, "Hydroxyl-terminated telechelic polydiene stars" (1996). Doctoral Dissertations Available from Proquest. AAI9619426.
https://scholarworks.umass.edu/dissertations/AAI9619426