The polymerization of 3,3″‐dialkylterthiophenes overcomes the lack of regiospecificity associated (to some extent) with all the polymerization methods in use, thus allowing the preparation of perfectly regioregular polymers endowed with enhanced electrical and optical properties. Moreover, the larger spacing of the alkyl chains achieved with the insertion of an unsubstituted thiophene unit confers to such regioregular polymers an extraordinary doping stability. Two regiochemically defined alkoxy‐substituted terthiophenes were also polymerized and the effects of the effects of the presence and position of the alkoxy group on the polymerization reaction and on the polymer properties are discussed. © 1993 John Wiley & Sons, Inc.

A set of segmented poly(ester-urethane)s were prepared from diisocyanates HDI or MDI and using 1,4-butanediol and D-glucose-derived cyclic diols (1,4 : 3,6-dianhydro-D-glucitol (isosorbide) or 2,4;3,5-di-O-methylidene-D-glucitol (gludioxol) or mixtures of them) as extenders. Hydroxyl end-capped polycaprolactone with a molecular weight of 3000 gÁmol À1 was used as soft segment. Two polymerization methods, in solution and in bulk, were applied for the synthesis of these poly(ester-urethane)s. The influence of the preparation procedure and composition in cyclic extender on synthesis results, structure, and properties of the novel poly(ester-urethane)s was comparatively evaluated and discussed. The effect of replacement of 1,4-butanediol by isosorbide or gludioxol on hydrodegradability was also assessed; the hydrolysis rate increased noticeably with the presence of glucitol derived units, although degradation of the polymers took place essentially by hydrolysis of the polyester soft segment.

A set of linear polyurethanes containing isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4‐butanediol (BD), isosorbide (Is) or diisosorbide diurethanes (Is2HDI and Is2MDI) as diols. The thermal transitions, thermal stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those displayed by their polyurethane analogues entirely made of BD. It was found that incorporation of Is units in the polyurethane chain produced significant changes in Tg, Tm, and Td but no significant differences were noticed between copolymers made from Is or Is2 monomers. Degradation assays revealed that the presence of Is units increased slightly the hydrolysis rate of polyurethanes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A set of linear [m,n]‐type polyurethanes was synthesized by reaction of HDI or MDI with conveniently protected sugar alditols L‐threitol (LTh), L‐arabinitol (LAr) and xylitol (Xy). $\overline M _{\rm n}$ of the resulting polyurethanes ranged between 10 000 and 60 000 with polydispersities around 2. They were thermally stable, showing no decomposition up to temperatures near 300 °C. They all were amorphous polymers with Tg highly dependent on the constitution of the diisocyanate, but scarcely dependent on the structure of the alditol. Hydrogenation of the LThBn‐HDI polyurethane yielded partially debenzylated products with Tg values ranging between 20 and 30 °C. Fully benzylated polyurethanes showed high resistance to hydrolytic degradation, whereas polyurethane with free hydroxyl side groups degraded significantly in saline buffer at pH = 10 and 37 °C.

Anodic coupling of 2,3,5-tris(4-pentoxy-2-thienyl)thiophene (an α,α-coupled terthiophene thiophene branched at the central thiophene ring) produces a polyconjugated polymer with a linear structure segmented by the thiophene branches. The conductivity (15 S cm-1), confined in a narrow potential window (0.3 V) by charge localization in tetrathiophene sequences, is strongly enhanced by occasional cross-linking in comparison with that of the polymer methyl-capped at the thiophene branches (0.02 S cm-1).