College of Science and Health Theses and Dissertations

Date of Award

Summer 8-22-2014

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Quinetta Shelby, Ph.D.

Second Advisor

Richard Niedziela, Ph.D.

Third Advisor

Paul A. Vadola, Ph.D.

Abstract

Electrophilic trisubstituted ethylenes, ring-substituted methyl 2-cyano-3-phenyl-2-propenoates, RPhCH=C(CN)CO2CH3 (where R is 2-CH3CO, 3-CH3CO, 2-CN, 4-N(CH3)2, 4-N(C2H3)2, 2-I, 4-I, 3-I-4-OCH3, 5-I-2-OCH3, 2,5-Br2, 3,5-Br2), were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution at 70 °C, using 1,1-azobis(cyclohexanecarbonitrile) as a radical initiator. Copolymer compositions were calculated from nitrogen elemental analysis and the structures were analyzed by IR, 1H- and 13C-NMR. The order of relative reactivity (1/r1) for the monomers is 4-I (10.6) > 2-I (6.8) > 2-CN (4.8) > 3-I-4-OCH3 (2.5) > 3-CH3CO (2.3) > 5-I-2-OCH3 (1.5) > 2-CH3CO (0.8) > 3,5-Br2 (0.6) > 2,5-Br2 (0.5) > 4-N(C2H3)2 (0.4) > 4-N(CH3)2 (0.3). Relatively high copolymer glass transition temperatures (Tg) in comparison with that of polystyrene indicates decreased chain mobility of the former due to the high dipolar character of the trisubstituted ethylene monomer unit.

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