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Isoprene and beta-myrcene were polymerized by anionic polymerization in bulk and in the 'green' ether solvents cyclopentyl methyl ether and 2-methyltetrahydrofuran and, for comparison, in cyclohexane and tetrahydrofuran. The polydienes produced in bulk and in cyclohexane contained high amounts of 1,4 units (>90%) whereas those produced in ether solvents were rich in 1,2 and 3,4 units (36%-86%). Comparison of the microstructures and glass transition temperatures of the polydienes obtained in the various solvents suggests that conventionally used solvents can be substituted by environmentally more friendly alternatives.
The aqueous self-assembly behavior of a series of poly(ethylene glycol)-poly(l-/d-lactide) block copolymers and corresponding stereocomplexes is examined by differential scanning calorimetry, dynamic light scattering, and transmission electron microscopy. Block copolymers assemble into spherical micelles and worm-like aggregates at room temperature, whereby the fraction of the latter seemingly increases with decreasing lactide weight fraction or hydrophobicity. The formation of the worm-like aggregates arises from the crystallization of the polylactide by which the spherical micelles become colloidally unstable and fuse epitaxically with other micelles. The self-assembly behavior of the stereocomplex aggregates is found to be different from that of the block copolymers, resulting in rather irregular-shaped clusters of spherical micelles and pearl-necklace-like structures.