Preparation, Characterization, and Properties of Alkali-Resistant and Hydrolysis-Resistant Silicone Surfactant

Chen, Y.; Tan, Wei; Li, Li; Ji, Hongbing

doi:10.3390/app13095726

Cited by 4 publications

(8 citation statements)

References 37 publications

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“…A detailed hydrolysis study on the commercial nonionic trisiloxane-polyoxyethylene surfactant Silwet L-77, where the effects of concentration, pH, and temperature were investigated, uses measurements of wetting, surface tension, turbidity, and gas chromatography . Another excellent study on zwitterionic sulfobetaine-siloxane surfactants uses surface tension measurements for surfactant degradation and gas chromatography to identify decomposition products in a study of hydrolytic decomposition over a pH range of 2–10. , Several more current siloxane surfactant studies report hydrolysis issues, with most using surface tension and/or spreading measurements − but some using chromatographic and/or spectroscopic methods. , …”

Section: Resultsmentioning

confidence: 99%

“…Details of these issues are further discussed in Supporting Information, Section I. Also in this section, hydrosilylation catalytic reactivity issues are described, surfactant purification procedures with impurity diagnostics are presented along with 1 H and 29 Si NMR spectra of the purified surfactant products with resonance assignments.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…The first fraction displayed no reagent or byproduct resonances and appeared to be very pure. See Figure SI-8 for its 29 Si NMR spectrum and assignments. The CH 2 Cl 2 filtrate fraction was relatively clean with a few very weak impurity resonances in its NMR spectrum.…”

Section: Si4sb N-[3′-tris(trimethylsiloxy)silyl-1′-propylene]-nn-dime...mentioning

confidence: 99%

“…The CH 2 Cl 2 filtrate was evaporated to dryness to yield 4.05 g (26%) of a colorless product, and the diethyl ether combined wash was evaporated to dryness to yield 4.15 g (27%) of a colorless product. See Figure SI-3 for NMR spectra of these three fractions and Figure SI-8 for the purified product 29 Si NMR spectrum and assignments. For reasons similar to the tetrasiloxane analogue, the latter two fractions were discarded.…”

Section: Si3sb N-[3′-bis(trimethylsiloxy)(methyl)silyl-1′-propylene]-...mentioning

confidence: 99%

“…Of interest is the resolution of the four nonequivalent Si-CH 3 resonances in the spectrum of the product fraction from a CD 3 OD solution compared with the overlapping of three of the four Si-CH 3 resonances in the spectrum from a D 2 O solution (see Figure SI-5). Also, see Figure SI-8 for the purified product 29 Si NMR spectrum and assignments.…”

Section: Cycsi4sb N-[3′-heptamethylcyclotetrasiloxy-1′-propylene]-nnd...mentioning

confidence: 99%

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Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Snow,

Ananth

2024

Langmuir

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The hydrolytic susceptibility of sulfobetaine-siloxane surfactants is investigated by comparison of a homologous series in this subclass of surfactants (R-(CH 2 ) 3 N + (Me) 2 (CH 2 ) 3 SO 3 − ; R = (Me 3 SiO) 3 Si-, (Me 3 SiO) 2 Si(Me)-, (Me 2 SiO) 3 -Si(Me)-) with an analogue series of oxyethylene-siloxane surfactants (R-(CH 2 ) 3 (OCH 2 CH 2 ) 10.2 OH; R = (Me 3 SiO) 3 Si-, (Me 3 SiO) 2 Si-(Me)-, (Me 2 SiO) 3 -Si(Me)-). Nuclear magnetic resonance (NMR) monitoring of these surfactants in an aqueous solution shows that the presence of the sulfobetaine head structure greatly enhances the hydrolysis rate of the siloxane tail as compared with oxyethylene-siloxane analogue control experiments. This sulfobetaine effect is confirmed by adding a model compound, (Me) 3 N + (CH 2 ) 3 SO 3 − , to the oxyethylene-siloxane surfactants and observing the large hydrolysis enhancement. Measurements of pH indicate the sulfobetaine presence greatly enhances acidity, but rigorous analysis could discover no source of acid other than the presence of the sulfobetaine structure. Titration measurements confirmed the presence of a tightly bound hydration layer of 4−7 water molecules per sulfobetaine group. It is speculated that the source of acidity may originate from an aqueous exclusion zone nucleated by the hydrated sulfobetaine at the interface of a sulfobetaine-siloxane surfactant bilayer aggregate. Hydrolysis prevention is investigated by addition of a pH 7 phosphate buffer, of an alkyl polyglycoside cosurfactant, and of a combination of both, with a finding of very significant but not complete suppression of the hydrolysis.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: Si4sb N-[3′-tris(trimethylsiloxy)silyl-1′-propylene]-nn-dime...mentioning

confidence: 99%

Section: Si3sb N-[3′-bis(trimethylsiloxy)(methyl)silyl-1′-propylene]-...mentioning

confidence: 99%

Section: Cycsi4sb N-[3′-heptamethylcyclotetrasiloxy-1′-propylene]-nnd...mentioning

confidence: 99%

See 3 more Smart Citations

Sulfobetaine-Siloxanes: A Class of Self-Destructive Surfactants

Snow,

Ananth

2024

Langmuir

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Statistical investigation of the experimental variables in the hydrosilylation reaction of a trimethylsiloxy‐terminated poly (methylhydro‐dimethyl)siloxane copolymer and an unsaturated polyethylene glycol using response surface methodology

Kamrani,

Barati,

Joshaghani

2024

Applied Organom Chemis

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The hydrosilylation reaction is a suitable route to prepare efficient, transparent, and low‐viscose silicone surfactants with low surface tension. Initial materials, the catalyst used, and experimental conditions are highly effective variables to achieve the maximum efficiency of the reaction, reduce the consumption of the catalyst, and prevent side reactions. To draw a comprehensive conclusion on the effect of these variables, a series of trimethylsiloxy‐terminated poly (methylhydro‐dimethyl)siloxanes copolymer (abbreviated as RSiH with different preceding numbers) and two unsaturated polyethylene glycols (UPEG200 and UPEG400) were selected, and the reactions in the presence of two platinum‐based catalysts, namely, hexachloroplatinic acid and ammonium hexachloroplatinate, were statistically studied by Design of Experiment. After initial pre‐investigations, the amounts of reactant and catalyst were subjected to analysis of variance using response surface methodology (RSM). Based on the results, low‐viscose and low‐surface tension silicone surfactants were obtained using UPEG400, RSiH105, and (NH4)2PtCl6 as catalysts, at temperatures over 170 °C. The best results were obtained with a relatively low concentration of the catalyst between 2.57 × 10−6 and 2.72 × 10−6 equivalent catalyst per UPEG. The relative equivalent ratio of [UPEG]/[RSiH] at the optimum condition was 1.6, which provided a surface tension below 21 mN/m together with a minimum amount of unreacted RSiH (less than 3%). The silicone surfactant was characterized as a pure product by a series of spectroscopic methods, such as FT‐IR and 1H NMR spectroscopies, as well as bromine number index. These excellent properties make this compound a new alternative in various industries.

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