Akademik Veri Yönetim Sistemi
EUROPEAN POLYMER JOURNAL, cilt.30, sa.9, ss.1037-1041, 1994 (SCI-Expanded)
Block copolymers were synthesized by sequential anionic polymerization of isoprene and t-butyl acrylate using sec-butyl lithium as initiator and tetrahydrofuran as solvent. The copolymers were fractionated by liquid/liquid separation to remove traces of homopolymer impurities, using toluene/methanol as a solvent/non-solvent system. Molecular characterization of the block copolymers was carried out using gel permeation chromatography, elemental analysis, Fourier transform infrared spectroscopy and static light scattering. The copolymers were shown by light scattering to form micelles in n-octane, a selectively bad solvent for the poly(t-butyl acrylate) block. Increasing the temperature led to a shin in the micelle/free-chain equilibrium in favour of free-chains. Contributions to the standard Gibbs energy of micellization were evaluated. A large, negative standard enthalpy of micellization is shown to provide the driving force for micellization.