In situ synthesis of polyisoprene/grafted single-walled carbon nanotube composites

Cui, Liqiang; Yu, Junsheng; Yu, Xinge; Lv, Yinghai; Li, Guijiang; Zhou, Shixue

doi:10.1038/pj.2012.225

Cited by 8 publications

(5 citation statements)

References 24 publications

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“…Calculations are performed for a realistic system, polyisoprene natural rubber (PINR) in acetone–benzene mixture, which provides an opportunity for correlation with experiments. Polyisoprene chains are commonly used for functionalization of particles of various sizes and chemistry, including macroscopic silica particles applied in rubber tires, polymeric and metal particles for nanocomposites, , and even single-wall carbon nanotubes . Acetone (A) and benzene (B) are common solvents, which are mutually miscible at ambient conditions; acetone is a bad solvent and benzene is a good solvent for PINR.…”

Section: Introductionmentioning

confidence: 99%

Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

2014

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Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

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Section: Introductionmentioning

confidence: 99%

Morphological Transformations in Polymer Brushes in Binary Mixtures: DPD Study

2014

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“…However, the homogeneous dispersion of CNTs is a difficult task mainly due to their poor solubility. Three different approaches have been adopted to produce polymer-functionalized CNTs: 345 (i) a non-covalent functionalization method by which polymers are produced by ring-opening metathesis polymerization (ROMP); 346,347 (ii) a covalent functionalization performed by first grafting polymerization initiators onto the tubes through covalent bonds and then exposing these CNT-based macroinitiators to the monomer, the polymer being obtained by anionic polymerization, 348 reversible addition and fragmentation chain transfer (RAFT) polymerization, 349 atom-transfer radical polymerization (ATRP) 350,351 or ROMP 352 and (iii) a functionalization performed by first grafting polymerization catalysts or co-catalysts (olefin polymerization via anchored metallocene catalysts [353][354][355][356] or ROMP 357,358 ). In this section, we will only discuss the latter approach.…”

Section: Polymerizationmentioning

confidence: 99%

Heterogeneous Catalysis on Nanostructured Carbon Material Supported Catalysts

2015

Nanostructured Carbon Materials for Catalysis

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For almost twenty years there has been an increasing interest in the use of nanostructured carbon materials as catalyst supports. 1-16 Following the nanotechnology wave, a wide variety of carbon nanomaterials has been investigated as catalyst supports, including fullerenes, CNTs, CNFs, carbon onions, nanodiamonds, FLG or GO. CNTs and CNFs, which constitute a new family of support offering a good compromise between the advantages of AC and high surface area graphite have been particularly studied. The main advantages offered by CNT or CNF supports are: 17 (i) the high purity of the material can avoid self-poisoning; (ii) the mesoporous nature of these supports can be of interest for liquid-phase reactions, thus limiting the mass transfer; (iii) the high thermal conductivity that limits hot-spots that can damage the catalyst; (iv) their well-defined and tunable structure; (v) their rich surface chemistry that offers numerous perspectives for adsorption and dispersion of the active phase; and (vi) the specific metal support interactions, due to high electrical conductivity of the support and to the tunable orientation of the graphene layers, that exist and that can directly affect catalytic activity and selectivity. The possibility to perform catalysis in a confined space is also of great interest. 6,18 From a theoretical viewpoint, graphene provides the ultimate two-dimensional model of a catalytic support. The reason is related to its high theoretical surface area (ca. 2630 m 2 g −1 ), high conductivity, unique graphitized basal plane structure and chemical tolerance. FLG,

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“…The new PIp−SWNT nanocomposites showed a significant improvement in thermal properties. 54 Similarly, secbutyllithium was employed to introduce negative charges on carbon nanocapsules, and these carbanions were used as initiators for anionic polymerization of styrene. The process resulted in polystyrene-grafted carbon nanocapsules.…”

Section: Organometallic Chemistry Of Carbonmentioning

confidence: 99%

“…The formation of carbanions on the SWNT surface facilitated the separation of the nanotubes in solution and enabled the production of homogeneous PIp rubber composites with well-dispersed nanotubes. The new PIp–SWNT nanocomposites showed a significant improvement in thermal properties . Similarly, sec -butyllithium was employed to introduce negative charges on carbon nanocapsules, and these carbanions were used as initiators for anionic polymerization of styrene.…”

Section: Organometallic Chemistry Of Carbon Nanotubesmentioning

confidence: 99%