The dynamics of poly(2-vinylpyridine) (P2VP) have been studied as a function of temperature (in the range from 123 to 453 K), pressure (0.1-270 MPa), and molecular weight (1.1 × 10 3 -3.0 × 10 4 g/mol), using dielectric spectroscopy (DS) within the frequency range from 10 -2 to 10 6 Hz. Structural methods (wide-angle X-ray scattering) have been employed in parallel with thermodynamic methods (pressure-volume-temperature). Three relaxation processes were found: two above the glass temperature (Tg) associated with the segmental (R-) process and a slower process with an apparent activation volume comparable to the monomer volume and another well below Tg, with an Arrhenius T dependence (βprocess). The results from the dynamic study combined with the thermodynamic results revealed that both decreasing thermal energy and insufficient volume lead to glass formation at lower temperatures, with the former having the stronger effect at temperatures near Tg (i.e., values of the ratio of apparent activation energies at constant volume and constant pressure in the range QV/QP ∼ 0.6-0.85 for the different temperatures and pressures investigated).

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Stryrenic macromonomers of polybutadienes (sMMB) were synthesized by selective reaction of living polybutadienes with the silyl chloride group of 4-(chlorodimethylsilyl)styrene. Anionic copolymerization of sMMBs with butadiene, in the presence of a randomizer (potassium 2,3-dimethyl-3-pentoxide randomizer), led to living random comb polybutadienes (PBCs). Taking advantage of the living character of the PBCs, a number of well-defined comb, star-comb, and comb-on-comb polybutadienes were synthesized by using high-vacuum techniques. All samples prepared were characterized by size exclusion chromatography (SEC) with DRI detector and SEC with two-angle laser light scattering detector (SEC-TALLS).

The following block–comb/graft copolymers of styrene (S), isoprene (I), and butadiene (B)—PS‐b‐(PB‐g‐PB), PS‐b‐(PB‐g‐PB)‐b‐PS, (PB‐g‐PB)‐b‐P2VP, (PS‐g‐PB)‐b‐(PI‐g‐PS), (PS‐g‐PB)‐b‐(PI‐g‐PS)‐b‐(PB‐g‐PI), (PS‐g‐PB)‐b‐(PI‐g‐PS)‐b‐(PB‐g‐PI)‐b‐(PI‐g‐PS)‐b‐(PS‐g‐PB), and (PS)2(PB‐g‐PB) [where PS is polystyrene, PB is polybutadiene, P2VP is poly(2‐vinylpyridine) (2VP), and PI is polyisoprene]—were synthesized with the macromonomer strategy and anionic polymerization high‐vacuum techniques. The synthetic approach involves the synthesis and block copolymerization of styrenic macromonomers in situ without isolation. The prepared samples were characterized by size exclusion chromatography with a differential refractometer detector, size exclusion chromatography with a two‐angle laser light scattering detector, and NMR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4040–4049, 2005