Non-balanced preparation method for double functionally-terminated polysiloxane from cyclicsiloxane anion actuated by silanol dipotassium salt

A technology of cyclosiloxane and polysiloxane, which is applied in the field of cyclosiloxane anionic non-equilibrium polymerization

Active Publication Date: 2009-07-01
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present inventor once disclosed in the patent application number: 200410009940.3 that anionic ring-opening non-equilibrium polymerization of cyclosiloxane initiated by aliphatic potassium alkoxide was used to prepare polysiloxane with monofunctional end group, but did not involve the use of diorganosilicon di Dipotassium alcohol salt is used as an initiator to initiate anionic ring-opening non-equilibrium polymerization of cyclosiloxane to prepare a method for difunctional end-group polysiloxane

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 2.3g of dimethylsilanediol and 2.0g of potassium metal were added to 20ml of benzene at the same time, stirred and reacted for 5 hours at 20°C to obtain dipotassium dimethylsilanediol (Me 2 Si(OK) 2 ) initiator, remove metal potassium by filtration under air-isolated conditions, then remove benzene under reduced pressure, and fill the prepared Me with nitrogen protection. 2 Si(OK) 2 Initiator.

[0026] In the three-necked flask, pass nitrogen gas to deoxygenate and dehumidify. Add hexamethylcyclotrisiloxane (D 3 ) 22.2g, dipotassium dimethylsilanediol (Me 2 Si(OK) 2 ) 0.336g, 20ml tetrahydrofuran (tetrahydrofuran is used both as a solvent and as an accelerator), and polymerized with electromagnetic stirring at 25°C. Viscosity increases after 0.5 hours, after 3 hours 29 Si-NMR detection monomer conversion rate was 95%. Capping with 0.2ml of water, filtering, removing the solvent under reduced pressure, and detecting the polymer molecular weight M by GPC n =10500...

Embodiment 2

[0028] 3.8g of methylphenylsilanediol and 2.0g of metal potassium were added to 20ml of tetrahydrofuran at the same time, and the reaction was stirred at 10°C for 6 hours to obtain dipotassium methylphenylsilanediol (MePhSi(OK) 2 ) initiator, remove metal potassium by filtration under air-isolated conditions, then remove tetrahydrofuran under reduced pressure, and fill the prepared MePhSi(OK) with nitrogen protection 2 Initiator.

[0029] In the three-necked flask, pass nitrogen gas to deoxygenate and dehumidify. Add octamethylcyclotetrasiloxane (D 4 ) 29.6g, dipotassium methylphenylsilanediol (MePhSi(OK) 2 ) 0.230g, 0.5ml dry dimethyl sulfoxide, polymerized with electromagnetic stirring at 30°C. Viscosity increases obviously after 1 hour, after 3 hours 29 Si-NMR detection monomer conversion rate was 90%. It was dissolved in 20 ml of toluene and capped with 0.5 ml of iodomethane. Filter, remove solvent under reduced pressure, GPC detects polymer molecular weight M n =26...

Embodiment 3

[0031] Add 5.4g of diphenylsilanediol and 2.0g of metal potassium to 40ml of benzene and tetrahydrofuran mixture (volume ratio: 1:1) at the same time, stir and react at 15°C for 6 hours to obtain dipotassium diphenylsilanediol (Ph 2 Si(OK) 2 ) initiator, remove metal potassium by filtration under air-isolated conditions, then remove benzene and tetrahydrofuran under reduced pressure, and fill the prepared Ph 2 Si(OK) 2 Initiator.

[0032] In the three-neck flask, pass argon gas to deoxygenate and dehumidify. Join D 4 29.6g, dipotassium diphenylsilanediol (Ph 2 Si(OK) 2 ) 0.146g, 0.3ml dry N-methylpyrrolidone, 20 ℃ mechanical stirring polymerization. Viscosity increases after 1 hour, after 5 hours 29 Si-NMR detection monomer conversion rate was 95%. It was dissolved in 30 ml of tetrahydrofuran and capped with 0.2 ml of trimethylchlorosilane. Filter, remove solvent under reduced pressure, GPC detects polymer molecular weight M n =57300.

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Abstract

The invention belongs to the field of cyclosiloxane anion non-equilibrium polymerization, in particular to a method for preparing difunctional terminal polysiloxane by initiating cyclosiloxane anion non-equilibrium polymerization with silanol dipotassium salt. The invention uses diorganosilanediol dipotassium salt as an initiator to initiate the anionic non-equilibrium polymerization of cyclosiloxane in bulk or in solution to prepare bifunctional terminal polysiloxane. The conversion rate of polysiloxane monomer prepared by this method can reach 90-95%. The obtained high-purity polysiloxane is suitable for use in fields requiring high-purity silicone rubber, such as aerospace, high-performance electronic products, and the like.

Description

technical field [0001] The invention belongs to the field of cyclosiloxane anion non-equilibrium polymerization, in particular to a method for preparing difunctional terminal polysiloxane by initiating cyclosiloxane anion non-equilibrium polymerization with silanol dipotassium salt. Background technique [0002] Difunctionally terminated polysiloxanes are usually prepared by anionic or cationic ring-opening polymerization of cyclosiloxanes. Anionic ring-opening polymerization (base-catalyzed polymerization) of cyclic siloxane is generally carried out with alkali metal hydroxide (such as potassium hydroxide, sodium hydroxide), quaternary ammonium hydroxide (such as tetramethylammonium hydroxide) and quaternary phosphine Oxide (such as tetrabutylphosphorus hydroxide) is used as an initiator to directly initiate the ring-opening polymerization of cyclosiloxane. This method either requires a higher polymerization temperature (potassium hydroxide, above 140°C), or the removal of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/06C08G77/08
Inventor 张勇张志杰汪倩谢择民
Owner INST OF CHEM CHINESE ACAD OF SCI
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