Emulsion polymerization of dimethylcyclosiloxane in cationic emulsion: mechanism study utilizing two phase liquid–liquid reaction kinetics

Gee, Ronald P.

doi:10.1016/j.colsurfa.2015.05.033

Cited by 11 publications

(10 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reduction over time, of the peak corresponding to OH groups exist only at the end of the polymer chains of PDMS synthesized by Maghnite-H + was shown by the infrared analysis (Figure 2), it indicates that the chains became longer, resulting in large molecular mass. The temporary stabilization between 8 and 10 h of the average molecular mass and, at the same time, the increase in the monomer conversion, due to the crosslinking phenomenon leading to branched structures because of the formation of ethylene bridges between the linear chains; this explanation is clearly supported by what has been obtained by 13 C NMR analysis (Figure 4c). The decrease in the average molecular mass after 10 h can be explained by backbiting degradation in the growing polymer chains, which generates oligomers and cyclic polysiloxanes of varying sizes, thereby increasing the polydispersity index (Table 2).…”

Section: Effect Of Maghnite-h+/monomer Weight Ratiosupporting

confidence: 76%

“…The characterization methods (IR, 1 H NMR, 13 C NMR and DSC) showed no difference either in the molecular structure, or in the thermal properties of the PDMS obtained compared to those obtained subsequently by other catalysts. The evolution of the average molecular mass, and the polydispersity index as a function of the operating conditions were followed by GPC, the best result was obtained at t = 8 h, T = 70 °C and Maghnite-H + / D8 weight ration = 4 %.…”

Section: Discussionmentioning

confidence: 99%

“…The spectrum of the monomer was characterized by a single peak at approximately 0.12 ppm corresponding to the carbon of CH3 (Figure 4a). The other two spectra correspond to 13 C NMR spectrum of the polymer obtained after 8 h (Figure 4b) and the DEPT-135 spectrum of the polymer obtained after 10 h (Figure 4c), Both spectra have a characteristic peak at 0.2 ppm, which corresponds to methyl groups in the polymer chain. Moreover, there was the creation of a down peak at 32.61 ppm for the polymer obtained after 10 h, that is attributed to the carbon of CH2, indicating the formation of ethylene bridges between linear polymer chains.…”

Section: Carbon Nuclear Magnetic Resonance ( 13 C Nmr)mentioning

confidence: 99%

“…It was therefore necessary to analyze the products obtained by 13 C NMR to provide a complement to the previous study. The results are shown in Figures 4a, 4b and 4c.…”

Section: Carbon Nuclear Magnetic Resonance ( 13 C Nmr)mentioning

confidence: 99%

“…We are interested in the polymerization of D8 (Scheme 1a) by Maghnite-H + . The polymerization of siloxane monomers was carried out previously by different catalysts as phosphazene bases [11,12], strong bases [13,14], dodecylbenzenesulfonic acid [15], triflic acid [16], tris(pentafluorophenyl)borane [17] and trifluoromethanesulfonic acid [18].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Green Polymerization of Hexadecamethylcyclooctasiloxane Using an Algerian Proton Exchanged Clay Called Maghnite-H+

Kherroub¹,

Belbachir

Lamouri

2017

Bull. Chem. React. Eng. Catal.

View full text Add to dashboard Cite

The purpose of this study was to synthesize polydimethylsiloxanes by heterogeneous catalysis, based on the polymerization of the hexadecamethylcyclooctasiloxane (D8) by an environment-friendly solid catalyst (Maghnite-H + ). Maghnite-H + is a natural Algerian clay of the montmorillonite type, prepared by activation with sulfuric acid, the impact of this activation was observable in the XRD spectrum, by the increase in the interlayer spacing (d001) resulting from the intercalation of hydronium ions between layers. The molecular structure of the obtained polymer was determined by different chemical methods of analysis such as IR, 1 H NMR, and 13 C NMR. The thermal behavior of the polysiloxane obtained was confirmed by DSC. In order to achieve the best possible yield and at the same time to get a polymer of high molecular mass, the operating conditions have been set at t = 8 h and T = 70 °C after the reaction was repeated several times. The average molecular mass and the polydispersity index were measured by GPC. A reaction mechanism has been suggested to show the action of the Maghnite-H + during the reaction.

show abstract

Section: Effect Of Maghnite-h+/monomer Weight Ratiosupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Carbon Nuclear Magnetic Resonance ( 13 C Nmr)mentioning

confidence: 99%

“…It was therefore necessary to analyze the products obtained by 13 C NMR to provide a complement to the previous study. The results are shown in Figures 4a, 4b and 4c.…”

Section: Carbon Nuclear Magnetic Resonance ( 13 C Nmr)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Green Polymerization of Hexadecamethylcyclooctasiloxane Using an Algerian Proton Exchanged Clay Called Maghnite-H+

Kherroub¹,

Belbachir

Lamouri

2017

Bull. Chem. React. Eng. Catal.

View full text Add to dashboard Cite

show abstract

Ionic and Coordination Ring‐Opening Polymerization

Penczek¹,

Biela²,

Cypryk³

et al. 2022

Macromolecular Engineering

View full text Add to dashboard Cite

This article provides the up‐to‐date and comprehensive review (over 700 citations) of all the important subjects of the ring‐opening polymerization (ROP) methods of polymers syntheses. This is the method of synthesis of several important classes of polymers that cannot be prepared in a different way (e.g., polyethers). It also complements known methods of polycondensation and ROP often is the method of choice. ROP is particularly important in syntheses of the biodegradable polymers‐polylactide and poly(ε‐caprolactone), discussed in details. Applications of these polymers, as well as polysiloxanes in biomedical applications are irreplaceable in the modern medicine. Either as bulk polymers or as nano‐ and microspheres, described In this article separately. There are sections in the present version that were not presented in the previous editions. This is description of polyoxazolines, polymers with phosphorus atoms in the chains, as well as mentioned above polysiloxanes an microspheres. We introduced also section describing novel analytical methods, particularly useful in studies of polymers with various architectures (star shape, multibranched etc.). Besides the synthetic aspects of ROP, this article describes thermodynamics and kinetic features of the living/controlled polymerizations, particularly by activated monomer mechanism and importance of dormant polymers in precision syntheses of desired structures.

show abstract

A New Interpretation of Apparent Induction Period in Ring‐Opening Polymerization of Octamethylcyclotetrasiloxane in Acid Emulsion

Suzuki

Totsuka

Ishiguro

et al. 2020

Macro Reaction Engineering

View full text Add to dashboard Cite

A following new interpretation of apparent induction period is proposed considering the experimental results obtained: octamethylcyclotetrasiloxane (D4) is activated by the reaction with acid to generate an activated derivative (A4). A4 reacts with D4 to generate A8, an active species containing eight dimethylsiloxane units. A8 backbites to generate mostly A4 and D4, which causes retardation in polymerization, but occasionally to form A3 and D5. A3 is highly reactive, and when the concentration of A3 exceeds a certain limit, much Ai where i is large enough is formed and promotes fast growth of chain at the interfacial area due to high concentration of D4. The interpretation assumes that A3 accelerates growth of chain faster than other species, and that A8 tends to backbite rather than grow. The interpretation is supported by the experimental results of polymerization conducted with D4 and D3, or D5 and D3 charged.

show abstract

Emulsion polymerization of dimethylcyclosiloxane in cationic emulsion: mechanism study utilizing two phase liquid–liquid reaction kinetics

Cited by 11 publications

References 14 publications

Green Polymerization of Hexadecamethylcyclooctasiloxane Using an Algerian Proton Exchanged Clay Called Maghnite-H+

Green Polymerization of Hexadecamethylcyclooctasiloxane Using an Algerian Proton Exchanged Clay Called Maghnite-H+

Ionic and Coordination Ring‐Opening Polymerization

A New Interpretation of Apparent Induction Period in Ring‐Opening Polymerization of Octamethylcyclotetrasiloxane in Acid Emulsion

Contact Info

Product

Resources

About