Journal of Polymer Science Part A: Polymer Chemistry

Journal of Polymer Science Part A: Polymer Chemistry, 2010

Catalytic cyclopropanation of commercial 1,2-or 1,4cis-polybutadiene, respectively, with ethyl diazoacetate catalyzed by [Tp Br3 Cu(NCMe)] (Tp Br3 ¼ hydrotris(3,4,5-tribromo-1-pyrazolyl)borate) at room temperature afforded high molecular weight (M n > 10 5 mol À1 ) side-chain or main-chain, respectively, carboxyethyl cyclopropyl-substituted polymers with variable and controlled degrees of functionalization. Complete functionalization of 1,4-cis-polybutadiene afforded poly[ethylene-alt-(3-ethoxycar-bonyl-cyclopropene)]. Catalytic hydrogenation of residual double bonds of partially cyclopropanated polybutadienes provided access to the corresponding saturated polyolefins. Thermal properties are reported. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4439-4444, 2010

European Polymer Journal, 2004

The monomer b-myrcene, a renewable resource, was polymerized in cyclohexane using two different Ziegler-Natta catalyst systems based on neodymium Nd(Oi-Pr) 3 and NdV 3. The Nd(Oi-Pr) 3 was combined with [HNMe 2 Ph][B(C 6 F 5) 4 ] (or [CPh 3 ][B(C 6 F 5) 4 ]) and Al(i-Bu) 3 (or Al(i-Bu) 2 H). Next, the NdV 3 was activated using Al(i-Bu) 3 and AlEt 2 Cl. Both catalyst systems exhibited high polymer yields near 100 % in the established reaction time, high polymer molecular masses, and broad molecular mass distributions. The catalyst systems gave an effective and stereospecific polymerization reaction of b-myrcene providing high cis selectivity of 1,4-polymyrcenes (> 92 %) with a glass transition temperature between À66 and À62 8C. The above-mentioned features of resulting elastomers in conjunction with the polymer's molecular masses and molecular mass distributions proved to be sensitive to borane and alkylaluminum compounds molar ratios, [B]/[Nd] and [Al]/[Nd] using Nd(Oi-Pr) 3 and [Cl]/[Nd] and [Al]/[Nd] with NdV 3 .

Macromolecular Rapid Communications, 2011

Macromolecules, 2008

Macromolecules, 2001

The synthesis of an H-shaped polybutadiene homopolymer as well as its detailed structural characterization is investigated. Anionic polymerization techniques together with chlorosilane linking agents were used for the production of the material. After each reaction step samples were taken and analyzed by size exclusion chromatography (SEC), membrane osmometry (MO), NMR, and temperature gradient interaction chromatography (TGIC). According to the characterization by SEC, MO, and NMR, the H-polymer showed a high degree of structural uniformity after purification by fractionation, and no significant amounts of differently branched byproducts could be detected. The TGIC analysis however revealed the presence of large amounts of structures, mainly with lower branching degree.We also found that a significant isotope effect exists in the TGIC retention between deuterated and hydrogenous polymers. In our case, where the H-polymer is partially deuterated, the TGIC analysis enabled us to resolve all the side products. Comparison of the different analysis methods indicates that the precise structural analysis of branched model polymers such as the H-polymer requires more sophisticated methods than used in the past.

Macromolecules, 2008

The synthetic strategy employs classical anionic polymerization using high-vacuum techniques and utilizes a difunctional linking agent 4-(dichloromethylsilyl)diphenylethylene (DCMSDPE). The synthesis involves (a) growing a living PBd chain using s-BuLi as initiator in benzene at room temperature, (b) titration of DCMSDPE with living PBdLi, (c) addition of s-BuLi to activate the double bond of DPE, (d) subsequent addition of butadiene to generate a living " 1 / 2 H", which has two arms and half of the final crossbar , and (e) finally coupling the two " 1 / 2 H" molecules with dichlorodimethylsilane to produce an H-PBd, which has two arms attached to each end of the crossbar. The weight-average molecular weight, number-average molecular weight, molecular weight distribution, intrinsic viscosity, and radius of gyration were characterized by multidetector size exclusion chromatography (SEC) coupled with a refractive index detector, a two-angle (15°and 90°) light scattering detector, and a Viscotek differential viscometer in tetrahydrofuran at 40°C. The H-PBds showed narrow and symmetrical molecular weight distributions (polydispersity indices, PDI) 1.03-1.06). Furthermore, the use of light scattering detectors showed that there were no detectable high molecular weight, more highly branched components present in these materials. This is an important advantage of this novel approach over previous synthetic routes to H-polymers. The values of the branching parameters g (0.58-0.77) and g′ (0.60-0.75) in the thermodynamically good solvent, tetrahydrofuran, are consistent with values reported previously by Roovers and Toporowski for H polystyrenes in the good solvent toluene. Effects of architecture on the branching parameters are elucidated.

Macromolecular Chemistry and Physics, 2014

Synthesis of a multiblock copolymer composed of cis-1,4-polybutadiene (PBd) segments and poly(3-buten-1-ol) segments is performed via successive hydroboration and oxidation of cis-1,4/ syn-1,2-multiblock PBd. The ratio of functionalization can be controlled by changing the amount of the borane reagent. The obtained polymer shows two distinctive glass-transition temperatures, which correspond to the cis-1,4-PBd block and the poly(3-buten-1-ol) block. These thermal properties clearly show that the functionalization of the PBd proceeds keeping the elastic property derived from cis-1,4 segment.

Journal of Polymer Science Part A: Polymer Chemistry, 2005

2,3,4,5,6-Pentafluorostyrene (PFS) was copolymerized with polybutadiene (PB) in tetrahydrofuran using benzoyl peroxide as the initiator at 50, 60, and 80 8C. The copolymerizations follow typical radical polymerization kinetics and behavior. The grafting parameters were evaluated as a function of monomer conversion, initiator concentration, and/or temperature by gel permeation chromatography of directly injected copolymerization mixtures. The grafting efficiencies and grafting ratios are most consistent with a system that terminates by combination and whose graft sites are generated by hydrogen abstraction of allylic radicals by primary initiator radicals. Pure graft copolymers were isolated by extracting unreacted PB into hexanes and PPFS homopolymer into acetone. The similarity of the glass transition temperatures of the PPFS grafts and the corresponding extracted PPFS homopolymers confirms that their lengths are approximately equal. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2874-2891, 2005

Polymer Chemistry, 2013

The ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) has been achieved with Grubbs 2 nd generation ruthenium catalyst in the presence of vinyl or acryloyl derivatives of glycerol carbonate. Such asymmetric chain-transfer agents enabled the synthesis in high yields of a-cyclocarbonate,u-vinyl-poly(cyclooctene) (PCOE) and, more rewardingly, of the highly valuable a,u-dicyclocarbonate telechelic PCOE.

Journal of Applied Polymer Science, 2021

Polybutadiene has widespread use as a commodity as well as a specialty polymer, but currently, it is prepared from non-renewable feedstocks. Herein, we report the synthesis of rubbery unsaturated polycarbonates (RUPCs) as green alternatives for polybutadiene. We prepared two RUPCs (respectively, denoted as RUPC1 and RUPC2) via the copolymerization of carbon dioxide (CO2) and a mixture of saturated and unsaturated long-chain epoxides using a Co(III) catalyst. The RUPCs were reacted with a styrene monomer via free-radical polymerization to prepare RUPC-graft-Polystyrene. All of the prepared polymers were characterized by 1H nuclear magnetic resonance spectroscopy and gel permeation chromatography. For RUPC, the number average molecular weight (Mn) increased by three-fold after the grafting reaction. Differential scanning calorimetry analysis confirmed that the glass transition temperature (Tg) of the RUPCs were low (~ −40°C) and approached those of polybutadienes. After polystyrene chains had been grafted onto the RUPC backbone, the Tg increased to 81°C. These green RUPCs have the potential to replace non-renewable polybutadiene in some applications such as high impact materials.