Tunable, Catalyst-Free Preparation of Silicone Gels

Lu, Guanhua; Schneider, Alyssa F.; Vanderpol, Melanie; Lu, Emily K.; Wong, Michael Y.; Brook, Michael A.

doi:10.1021/acs.iecr.1c02369

Cited by 5 publications

(9 citation statements)

References 20 publications

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“…Two-component condensation also relies on a Sn-catalyst but does not require atmospheric moisture and therefore can be used to prepare larger objects. The use of Sn-catalysts may cause potential toxicity for implanted devices, particularly if levels are not minimized . Moisture-cured silicones also suffer from shrinkage caused by the evaporation of condensation products and so can present challenges for devices that require precise tolerances.…”

Section: Overview Of Silicone Cure Chemistriesmentioning

confidence: 99%

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

Marmo

Grunlan

2023

ACS Macro Lett.

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Silicones have a long history of use in biomedical devices, with unique properties stemming from the siloxane (Si–O–Si) backbone that feature a high degree of flexibility and chemical stability. However, surface, rheological, mechanical, and electrical properties of silicones can limit their utility. Successful modification of silicones to address these limitations could lead to superior and new biomedical devices. Toward improving such properties, recent additive strategies have been leveraged to modify biomedical silicones and are highlighted herein.

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Section: Overview Of Silicone Cure Chemistriesmentioning

confidence: 99%

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

Marmo

Grunlan

2023

ACS Macro Lett.

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“…With readily available starting materials, autooxidative curing of hydride terminated PDMS has recently been shown to produce silicone networks without the use of catalyst at temperatures above 220 °C. [7,8] As these conditions are unsuitable for industrial settings, a means to producing metal catalystfree RTV silicone networks is still needed.…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Polysilazanes Allows Catalyst‐Free Curing of Silicones

Sønderbæk‐Jørgensen

Meier

Dam‐Johansen

et al. 2022

Macro Materials & Eng

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Silicones are typically cured at room temperature by means of metal catalyst such as tin or platinum. When networks are formed, the catalyst becomes unrecoverable, which is of economic as well as environmental concern. Very few methods for producing metal catalyst-free room-temperature-vulcanized (RTV) silicones exist and require conditions unavailable in industrial settings. Through the study of organic polysilazane (PSz) reactivity with simple alcohols by nuclear magnetic resonance, an unexpected fragmentation preference is discovered for breaking the Si-N bond rather than the Si-H; thereby, casting a new light on the fragmentation mechanism of PSzs. Utilizing the PSz fragmentation as a silyl ether coupling agent for multifunctional carbinol silicones, a method of producing catalyst-free RTV silicone networks at ambient conditions is presented. These silicone networks are proven chemically similar to a standard condensation-cured silicone and stoichiometric variations of PSz content demonstrate adjustable network properties.

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“…All this emphasizes the necessity for novel metal‐free crosslinking methods. Alternative curing via autoxidation, [7,8] silacyclopropanes, [9] thiol‐enes, [10] polysilazanes, [11] or cyclic disulfides [12] has been introduced over the past years. While autoxidative curing can use readily available hydride‐terminated silicones, it is restricted to temperatures above 220 °C [8] .…”

Section: Introductionmentioning

confidence: 99%

“…Alternative curing via autoxidation, [7,8] silacyclopropanes, [9] thiol‐enes, [10] polysilazanes, [11] or cyclic disulfides [12] has been introduced over the past years. While autoxidative curing can use readily available hydride‐terminated silicones, it is restricted to temperatures above 220 °C [8] . Another heat‐controlled method is the curing of hydroxy‐terminated PDMS by using silacyclopropanes in a ring‐opening reaction.…”

Section: Introductionmentioning

confidence: 99%

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Photo‐Activity of Silacyclopropenes and their Application in Metal‐Free Curing of Silicones

et al. 2022

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Silicone elastomers are usually produced via addition or condensation curing by means of platinum‐ or tin‐based catalysis. The employed catalysts remain in the final rubber and cannot be recovered, thus creating various economic and environmental challenges. Herein, a light‐mediated curing method using multifunctional silacyclopropenes as crosslinker structures was introduced to create an effective alternative to the conventional industrial crosslinking. To evaluate the potential of the photoreaction a model study with small monofunctional silirenes was conducted. These investigations confirmed the required coupling reactivity upon irradiation and revealed an undesired rearrangement formation. Further optimization showed the reaction selectivity to be strongly influenced by the substitution of the three‐membered ring system and the reaction temperature. The synthesis of multifunctional silirenes was described based on the most suitable model compound to create active crosslinker scaffolds for their application in silicone curing. This photo‐controlled process produces catalyst and additive free elastomers from liquid silicones, including hydride‐, hydroxy‐, or vinyl terminated polydimethylsiloxanes.

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Tunable, Catalyst-Free Preparation of Silicone Gels

Cited by 5 publications

References 20 publications

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

Reactivity of Polysilazanes Allows Catalyst‐Free Curing of Silicones

Photo‐Activity of Silacyclopropenes and their Application in Metal‐Free Curing of Silicones

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