Facile synthesis of dendron-branched silicone polymers

Morgan, Jennifer; Chen, Tong; Hayes, R. L.; Dickie, Tara; Urlich, Tomas; Brook, Michael A.

doi:10.1039/c7py00260b

Cited by 27 publications

(26 citation statements)

References 15 publications

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“…When linear branches were placed on a low molecular weight linear silicone backbone, little change in resulting viscosity was noted, even at high branch frequencies. By contrast, the grafting of medium, and especially high density, 3D branches on the same backbone led to much higher increases in the viscosity at given frequency (Figure ) . It was also noted that there was a rise in viscosity with increasing branch frequency until a maximum occurred, at which point a globular transition occurred, and the viscosity began to drop with further increases in branch frequency; such a trend has been observed with dendrimers.…”

Section: Piers–rubinsztajn (Pr) Reactionmentioning

confidence: 73%

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New Control Over Silicone Synthesis using SiH Chemistry: The Piers–Rubinsztajn Reaction

Brook

2018

Chemistry A European J

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There is a strong imperative to synthesize polymers with highly controlled structures and narrow property ranges. Silicone polymers do not lend themselves to this paradigm because acids or bases lead to siloxane equilibration and loss of structure. By contrast, elegant levels of control are possible when using the Piers-Rubinsztajn reaction and analogues, in which the hydrophobic, strong Lewis acid B(C F ) activates SiH groups, permitting the synthesis of precise siloxanes under mild conditions in high yield; siloxane decomposition processes are slow under these conditions. A broad range of oxygen nucleophiles including alkoxysilanes, silanols, phenols, and aryl alkyl ethers participate in the reaction to create elastomers, foams and green composites, for example, derived from lignin. In addition, the process permits the synthesis of monofunctional dendrons that can be assembled into larger entities including highly branched silicones and dendrimers either using the Piers-Rubinsztajn process alone, or in combination with hydrosilylation or other orthogonal reactions.

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Section: Piers–rubinsztajn (Pr) Reactionmentioning

confidence: 73%

“…showed that, following the PR reaction, Huisgen or azide/alkyne click reactions could be used to create silicone/PEG (or cyclodextrin) surfactants (Figure B), elastomers (Figure C), copolymers or adhesives . The most important orthogonal reaction in silicone systems is platinum‐catalyzed hydrosilylation (see below) …”

Section: Piers–rubinsztajn (Pr) Reactionmentioning

confidence: 99%

New Control Over Silicone Synthesis using SiH Chemistry: The Piers–Rubinsztajn Reaction

Brook

2018

Chemistry A European J

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“…Monoallyl-terminated silicone dendrons with different degrees of branching were prepared as shown in Figure 2A [14]. First, allyltriethoxysilane underwent the Piers-Rubinsztajn (PR) reaction with either pentamethyldisiloxane ( T(DM) 3 series) or 1,1,1,1,3,5,5,5-heptamethyltrisiloxane ( T(TM 2 ) 3 series) to afford compounds 1 or 2 in good yield.…”

Section: Resultsmentioning

confidence: 99%

“…Mono-vinyl terminated PDMS 7 was prepared according to the literature procedure [14]. The Mn of this polymer was 3165 g mol −1 and dispersity ( Đ M ) was 1.2.…”

Section: Methodsmentioning

confidence: 99%

Hyperbranched Silicone MDTQ Tack Promoters

et al. 2019

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Low molecular weight, highly crosslinked silicone resins are widely used as reinforcing agents for highly transparent elastomers and adhesion/tack promoters in gels. The resins are complex mixtures and their structure / property relationships are ill defined. We report the synthesis of a library of 2, 3 and 4-fold hyperbranched polymeric oils that are comprised of linear, lightly branched or highly branched dendronic structures. Rheological examination of the fluids and tack measurements of gels filled with 10, 25 or 50% dendronic oils were made. Viscosity of the hyperbranched oils themselves was related to molecular weight, but more significantly to branch density. The properties are driven by chain entanglement. When cured into a silicone gel, less densely branched materials were more effective in improving tack than either linear oils or Me3SiO-rich, very highly branched oils of comparable molecular weight, because the latter oils underwent phase separation.

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“…Alternatively, the crosslinkers can be modified, but this approach dramatically decreases the achievable concentrations of high-permittivity filler. [87][88][89][90] By employing the covalent grafting method, immiscibility issues are avoided, of course provided that the reaction mixture was homogeneous initially and the curing did not alter this state. [86] Grafting often requires complex and novel chemistries, since the chemistry of silicones is rather unexplored.…”

Section: Chemically Modified Silicone Elastomersmentioning

confidence: 99%

Optimization Techniques for Improving the Performance of Silicone‐Based Dielectric Elastomers

Skov

2017

Adv Eng Mater

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Dielectric elastomers are possible candidates for realizing products that are in high demand by society, such as soft robotics and prosthetics, tactile displays, and smart wearables. Diverse and advanced products based on dielectric elastomers are available; however, no elastomer has proven ideal for all types of products. Silicone elastomers, though, are the most promising type of elastomer when viewed from a reliability perspective, since in normal conditions they do not undergo any chemical degradation or mechanical ageing/relaxation. Within this review, different pathways for improving the electro-mechanical performance of dielectric elastomers are highlighted. Various optimization methods for improved energy transduction are investigated and discussed, with special emphasis placed on the promise each method holds. The compositing and blending of elastomers are shown to be simple, versatile methods that can solve a number of optimization issues. More complicated methods, involving chemical modification of the silicone backbone as well as controlling the network structure for improved mechanical properties, are shown to solve yet more issues. From the analysis, it is obvious that there is not a single optimization technique that will lead to the universal optimization of dielectric elastomer films, though each method may lead to elastomers with certain features, and thus certain potentials.

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Facile synthesis of dendron-branched silicone polymers

Cited by 27 publications

References 15 publications

New Control Over Silicone Synthesis using SiH Chemistry: The Piers–Rubinsztajn Reaction

New Control Over Silicone Synthesis using SiH Chemistry: The Piers–Rubinsztajn Reaction

Hyperbranched Silicone MDTQ Tack Promoters

Optimization Techniques for Improving the Performance of Silicone‐Based Dielectric Elastomers

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