Introduction. Polymacromonomers 1-3 are comblike polymers with an extremely high-density branching, since each monomeric unit bears a polymeric chain. Depending on the degree of polymerization of the side and the main chain, they can form either starlike or brushlike (molecular brushes) structures. The most popular polymerization of macromonomers 4-6 is by using radical initiators. [7][8][9][10] Ring-opening (ROMP), 11,12 atom transfer radical (ATRP), [13][14][15][16][17] and Ziegler-Natta 18 polymerization of macromonomers 19 have also been reported in the literature. A few attempts have been undertaken for the anionic polymerization of macromonomers without complete success. 20 It seems that during the polymerization the growing macroanions are terminated by impurities accompanying the macromonomers. These impurities are introduced during the isolation step of macromonomer by pouring the macromonomer solution into the nonsolvent. Since macromonomers are solid materials, their purification to the standards required for anionic polymerization is extremely difficult.In this communication, we are proposing a new methodology to overcome this problem by synthesizing and polymerizing the macromonomer in the same reactor and by using high-vacuum techniques.Experimental Section. Purification of all monomers (isoprene, butadiene, styrene), solvents (benzene and tetrahydrofuran), and terminating agent (methanol) were performed using standard high-vacuum techniques, described in detail elsewhere. 21 sec-Butyllithium (sec-BuLi), prepared from sec-butyl chloride and lithium dispersion, was the initiator for all polymerizations. Magnesium turnings (Aldrich) were washed with THF and dried in the vacuum line. p-Chlorostyrene was distilled under vacuum, over calcium hydride, to ampules equipped with break-seals. 4-(Chlorodimethylsilyl)styrene (CDMSS) was prepared from the Grignard reagent of p-chlorostyrene and dichlorodimethylsilane, using high-vacuum techniques, as reported in detail recently. 22 Polymerizations and linking reactions were carried out in evacuated, n-BuLi-washed, and solvent-rinsed glass reactors. Reagents were introduced via breakseals, and aliquots for characterization were removed by heat-sealing of constrictions. Full details of the highvacuum techniques are given elsewhere. 21 The apparatus of Figure 1 was used for the synthesis and polymerization of macromonomers.

Model diblock copolymers of poly(1,4‐butadiene) (PB) and poly(dimethylsiloxane) (PDMS), PB‐b‐PDMS, were synthesized by the sequential anionic polymerization (high vacuum techniques) of butadiene and hexamethylciclotrisiloxane (D3) in the presence of sec‐BuLi. By homogeneous hydrogenation of PB‐b‐PDMS, the corresponding poly(ethylene) and poly(dimethylsiloxane) block copolymers, PE‐b‐PDMS, were obtained. The synthesized block copolymers were characterized by nuclear magnetic resonance (1H and 13C NMR), size‐exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and rheology. SEC combined with 1H NMR analysis indicates that the polydispersity index of the samples (Mw/Mn) is low, and that the chemical composition of the copolymers varies from low to medium PDMS content. According to DSC and TGA experiments, the thermal stability of these block copolymers depends on the PDMS content, whereas TEM analysis reveals ordered arrangements of the microphases. The morphologies observed vary from spherical and cylindrical to lamellar domains. This ordered state (even at high temperatures) was further confirmed by small‐amplitude oscillatory shear flow tests. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1579–1590, 2006

The synthesis of a model cyclic triblock terpolymer [cyclic(S‐b‐I‐b‐MMA] of styrene (S), isoprene (I), and methyl methacrylate (MMA) was achieved by the end‐to‐end intramolecular amidation reaction of the corresponding linear α,ω‐amino acid precursor [S‐b‐I‐b‐MMA] under high‐dilution conditions. The linear precursor was synthesized by the sequential anionic polymerization of S, I, and MMA with 2,2,5,5‐tetramethyl‐1‐(3‐lithiopropyl)‐1‐aza‐2,5‐disilacyclopentane as an initiator and amine generator and 4‐bromo‐1,1,1‐trimethoxybutane as a terminator and carboxylic acid generator. The separation of the unreacted linear polymer from the cyclic terpolymer was facilitated by the transformation of the unreacted species into high molecular weight polymers by the evaporation of the reaction solvent and the continuation of the reaction under high‐concentration conditions. The intermediate materials and the final cyclic terpolymer, characterized by size exclusion chromatography, vapor pressure osmometry, thin‐layer chromatography, IR and NMR spectroscopy, exhibited high molecular weight and compositional homogeneity. Dilute‐solution viscosity measurements were used as an additional proof of the cyclic structure. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1476–1483, 2002

Linear and symmetric star block copolymers of styrene and isoprene containing [C60] fullerene were synthesized by anionic polymerization and appropriate linking postpolymerization chemistry. In all block copolymers, the C60 was connected to the terminal polyisoprene (PI) block. The composition of the copolymers was kept constant (∼30% wt PI), whereas the molecular weight of the diblock chains was varied. The polymers were characterized with a number of techniques, including size exclusion chromatography, membrane osmometry, and 1H NMR spectroscopy. The combined characterization results showed that the synthetic procedures followed led to well‐defined materials. However, degradation of the fractionated star‐shaped copolymers was observed after storage for 2 months at 4 °C, whereas the nonfractionated material was stable. To further elucidate the reasons for this degradation, we prepared and studied a four‐arm star copolymer with the polystyrene part connected to C60 and a six‐arm star homopolymer of styrene. These polymers as well as linear copolymers end‐capped, through N<, with C60 were stable. Possible reasons are discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2494–2507, 2001

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