The Coupling of Synthetic and Biological Polymers: Silicone - Starch Composites

Abstract

<p> This thesis presents a study of the compatiblization of a hydrophobic, synthetic polymer, polydimethylsiloxane (PDMS) and a hydrophilic biopolymer, starch. The Diels- Alder adduct of cyclopentadiene and maleic anhydride, bicyclo[2.2.1]hept-5-ene-2,3- dicarboxylic-anhydride, (1), was hydrosilylated with hydride- terminated PDMS to yield α,ω-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic-anhydride-polydimethylsiloxane, (4) having an average molecular weight of 750 g mol^-1. This was then reacted with starch using dimethylaminopyridine as a catalyst in a dimethylsulfoxide medium at 80°C to yield a silicone-starch graft copolymer having a γ-carboxylic-ester linkage.</p> <p> In order to study the influences of the quantity of hydrophobic and hydrophilic components, a series of composites were synthesized varying the starch and silicone stoichiometry (series-1).</p> <p> In order to study the influence of the molecular weight of the silicone, 4 was redistributed with octamethylcyclotetrasiloxane (D4) via cationic polymerization to yield higher molecular weight derivatives. The products were 7 (1500 g mol^-1) and 8 (9000 g mol^-1). These were reacted with starch to give a series of composites for each molecular weight of the functionalized silicone.</p> <p> Spectroscopic and physical properties were analyzed for developing trends.</p>