Characterization of polydimethylsiloxane elastomer degradation via cross-linker hydrolysis

Lai, Samuel K.; Batra, Aman; Cohen, Claude

doi:10.1016/j.polymer.2005.02.051

Cited by 30 publications

(18 citation statements)

References 27 publications

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“…They introduced hydrolysis‐sensitive crosslinks into the PDMS network by employing 2,4,6‐triallyloxy‐1,3,5‐triazine as curing agent. Under humid conditions the crosslinks hydrolyzed and a degradation of the network was observed, which correlated well with crosslink density and degree of humidity …”

Section: Introductionmentioning

confidence: 55%

Dual‐Responsive Polydimethylsiloxane Networks

Giebler

Radl

Ast

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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Exploiting the salient features of o‐nitrobenzyl chemistry, this work aims at the preparation of polydimethylsiloxane networks that undergo well‐defined bond cleavage in response to either UV light or different pH values as external trigger. Polydimethylsiloxane (PDMS) oligomers with terminal anhydride groups are thermally crosslinked in the presence of a bi‐functional epoxy monomer containing a photolabile o‐nitrobenzyl ester (o‐NBE) group. The susceptibility of the ester groups toward hydrolytic cleavage reactions is used for a pH‐triggered network degradation. Sol–gel analysis confirms that the degradation time can be easily controlled by the base concentration over different time scales varying between hours and weeks. Along with classical ester hydrolysis, photoinduced degradation of the elastomeric networks is carried out by photoisomerization and cleavage of the o‐NBE links upon exposure with UV light. Positive‐tone patterns with a structure size of 100 μm are obtained by photolithographic techniques confirming the spatial control of solubility properties. However, by increasing the exposure dose, recrosslinking of the networks is observed due to side reactions of the primary photocleavage products. As the reformed crosslinks are less sensitive to ester hydrolysis, the side reactions are employed to inscribe negative‐tone microstructures in the PDMS network. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2319–2329

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Section: Introductionmentioning

confidence: 55%

Dual‐Responsive Polydimethylsiloxane Networks

Giebler

Radl

Ast

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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“…Analysis showed that the pre‐Soxhlet sample had a platinum content of 19 ppb and that 85% of the catalyst was removed by performing Soxhlet extraction. It should be noted that of the other known SiCE elastomers and resins where catalysts (platinum or other) were used in their syntheses, attempts to remove the catalyst by performing Soxhlet extractions were not employed . Figure shows the ATR FTIR analysis of SiCE‐H21 pre‐ and post‐Soxhlet extraction.…”

Section: Resultsmentioning

confidence: 99%

“…One avenue for circumventing the issue of incomplete curing of the CE groups would be to utilize a top‐down approach and prepare the CEs from monomers where the triazine cores are pre‐formed prior to obtaining the network. To the authors' knowledge, there is only brief mention of this in the literature . In a study presented in 2005 by Lai and co‐workers, the authors prepared two different siloxane elastomers by reacting 2,4,6‐tris(allyloxy)‐1,3,5‐triazine (TAC; Fig.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of siloxane‐based cyanate ester elastomers from readily available materials: a top‐down approach

Jennings

Morey

Guenthner

et al. 2016

Polymer International

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A number of siloxane‐based cyanate ester (SiCE) elastomers were prepared from commercially available starting reagents employing a hydrosilylation reaction. Each elastomer was designed to utilize 2,4,6‐tris(allyloxy)‐1,3,5‐triazine as a crosslinker and multifunctional vinyl component in the hydrosilylation reaction, ensuring that the triazine rings were completely formed, and thus the elastomers resemble fully cured cyanate ester networks. The hydride‐terminated siloxane components used were varied from small‐molecule siloxanes to pre‐polymers of different molecular weights. Attenuated total reflectance Fourier transform infrared analysis confirmed the successful hydrosilylation reaction and complete curing of the SiCE elastomers via functional group analysis. Thermal characterization by thermogravimetric analysis and differential scanning calorimetry demonstrated that thermal properties of the elastomers could be tailored depending on the type of siloxane component that was utilized. The gel content of the elastomers was also determined. Investigations into the effects of a platinum catalyst on the elastomers determined that the presence of the catalyst affected the thermochemical stability of the SiCE elastomers. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

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“…The presence of the acid in the RTV foam may lead to the polymer degradation by protonation of the siloxane chain, which eases the barrier for hydrolysis [26]. In order to demonstrate this effect, trimethyl-terminated polydimethylsiloxane samples were thermally aged in presence of octanoic acid and trace amounts of water.…”

Section: Catalytic Activity Of Tin Residuesmentioning

confidence: 99%

Aging mechanisms in RTV polysiloxane foams

Labouriau

Robison

Meincke

et al. 2015

Polymer Degradation and Stability

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a b s t r a c tThe long-term use of polysiloxane foams requires a good understanding of the diverse factors that may influence their performance. The aim of the present work was to understand the interplay between inservice environments and reactive species that reside in the foams. Two foams (SX358 and S5370) were thermally aged under compressive strain to gauge the onset of compression set, an indicator of degradation. Experiments were performed by either aging the foams in open air containers or in high humidity environments. Our results indicated that foams aged in open air environments exhibited less compression set than when aged in presence of moisture. These results were analyzed in terms of postcuring reactions, hydrolysis and rearrangement of the network, which are promoted by active residues that are left in the foam from the curing process. In particular, the residues from tin octoate, the catalyst used in the cure of the foams, were identified and their role in promoting aging was determined. Reactions were either catalyzed by tin(II) species or by a combination of trace amounts of water and octanoic acid, a product of the hydrolysis of tin octoate. More precisely, this work demonstrated that reactive residues promote chemical changes in the polymer, which resulted in compression set. On the other hand, the oxidized residues of the tin octoate show no catalytic activity towards promoting condensation reactions between silanol groups. Our work established that, depending on service conditions, certain residues are more harmful to the foam's lifetime than others.

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Characterization of polydimethylsiloxane elastomer degradation via cross-linker hydrolysis

Cited by 30 publications

References 27 publications

Dual‐Responsive Polydimethylsiloxane Networks

Dual‐Responsive Polydimethylsiloxane Networks

Synthesis and characterization of siloxane‐based cyanate ester elastomers from readily available materials: a top‐down approach

Aging mechanisms in RTV polysiloxane foams

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