Disclosure of Invention
Aiming at the defects of the prior art, particularly the problem that the polysiloxane is not easy to spin, and simultaneously, the invention solves the problem that the existing polysiloxane fiber cannot be recycled, and provides the sulfone-containing polysiloxane fiber and the preparation method thereof. The invention introduces sulfonyl group with larger polarity into the siloxane chain segment, changes the property of the main chain, prepares novel organic silicon fiber, and solves the problem that the existing siloxane is not easy to spin. The resulting sulfone-containing polysiloxanes are easy to spin and have very good thermal stability and, in particular cases, permit high-yield recycling of the monomers. The synthesis route of the sulfone-containing polysiloxane is simple and efficient, and the prepared sulfone-containing polysiloxane is easy to spin and has excellent temperature resistance and recyclability.
The technical scheme of the invention is as follows:
a sulfone-containing polysiloxane having the following structural formula:
wherein: r1Alkylene, arylene, alkylene ether, biphenylene, or diphenylene sulfide which is a linear or branched structure;
R2is hydrogen, methyl, ethyl, phenyl or trifluoropropyl, R in different positions2The substituents are the same or different;
n is 2 to 10, and m is 10 to 3000.
According to the invention, when R1When the alkyl or alkyl ether is used, the alkyl or alkyl ether is preferably C1-C10; further preferred R1Is butylene, 3, 6-dioxo-1, 8-octyl, 1, 4-xylylene or diphenylene sulfide.
According to the invention, it is preferred that the sulfone-containing polysiloxane has the formula:
R1is butylene, 3, 6-dioxo-1, 8-octyl, 1, 4-xylylene or diphenylene sulfide group;
R2is hydrogen, methyl, ethyl, phenyl or trifluoropropyl, R in different positions2The substituents are the same or different;
n is 3 to 9, and m is 50 to 2500.
According to the present invention, preferably, the polymerization degree m of the sulfone-containing polysiloxane is 100, and the weight average molecular weight is 42000.
According to the invention, the preparation method of the sulfone-containing polysiloxane comprises the following steps:
the preparation method comprises the steps of taking macrocyclic siloxane containing sulfone as a raw material, dissolving the macrocyclic siloxane in an organic solvent, and carrying out ring-opening polymerization reaction under the protection of protective gas and catalysis of a catalyst to obtain the macrocyclic siloxane.
According to the present invention, preferably, said sulfone-containing macrocyclic siloxane has the following structure:
wherein: r1、R2The same meanings as above, and n is 2 to 10.
Further preferably, said sulfone-containing macrocyclic siloxane has the following structure:
according to the present invention, the organic solvent is preferably one of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, and 1, 4-dioxane, and is more preferably dimethyl sulfoxide.
According to the present invention, the catalyst is preferably an inorganic base (hydroxides of lithium, sodium, potassium, ammonium, barium, sodium fluoride, etc.); organic bases (alkali metal salts of alcohols (e.g., sodium methoxide, sodium ethoxide, potassium tert-butoxide), organometallic compounds, such as alkyllithium reagents (e.g., butyllithium, diisopropylaminolithium, hexamethyldisilaaminolithium), grignard reagents (e.g., methylmagnesium iodide), quaternary ammonium hydroxides, lewis bases (e.g., organophosphorus, azacyclo-carbene and azacyclo-carbene, and phosphazene superbases)); inorganic acids (sulfuric acid, hydrochloric acid, nitric acid, boric acid, carbonic acid, phosphoric acid); or organic acids (trifluoromethanesulfonic acid, trifluoroacetic acid, mellitic acid, nitrilotriacetic acid, trichloroacetic acid, trinitrobenzenesulfonic acid or Lewis acids (e.g. Al (C)6F5)3、Zn(C6F5)3、B(C6F5)3) Indium chloride)). Further preferably, the inorganic base is KOH, the organic base is 1,5, 7-triazabicyclo (4.4.0) dec-5-ene, the inorganic acid is sulfuric acid, and the organic acid is trifluoroacetic acid.
According to the present invention, the ring-opening polymerization reaction temperature is preferably 0 to 250 ℃, more preferably 80 to 110 ℃, and most preferably 100 ℃.
According to the present invention, the ring-opening polymerization reaction time is preferably 4 to 48 hours, and more preferably 6 to 12 hours.
According to the present invention, preferably, the protective gas is any one of nitrogen, helium or argon, and further preferably nitrogen.
According to the invention, the molar ratio of the sulfone-containing macrocyclic siloxane to the catalyst is preferably 10-3000: 1, more preferably 50 to 100: 1.
the reaction scheme of the above preparation method of the sulfone-containing polysiloxane according to the present invention is as follows:
according to the invention, the preparation method of the sulfone-containing macrocyclic siloxane comprises the following steps:
mixing a monomer with sulfydryl at two ends, a vinyl siloxane monomer at two ends and a photoinitiator benzoin dimethyl ether (DMPA), wherein the molar ratio of the monomer with sulfydryl at two ends to the monomer with vinyl siloxane at two ends to the photoinitiator is 1: 0.5-1.5: 0.01, preferably 1: 1: 0.001, carrying out step-by-step mercaptoalkene polymerization reaction under ultraviolet light for 5-30 min, preferably 15min to obtain polysiloxane containing thioether; and dissolving the thioether-containing polysiloxane in a solvent, adding tetrahydrofuran as a preferable solvent, adding oxone, reacting at the temperature of 25-100 ℃, preferably 30 ℃ for 10-48h, preferably 24h under the protection of nitrogen, and obtaining the sulfone-containing macrocyclic siloxane as a polymeric monomer of the sulfone-containing polysiloxane.
The reaction route of the preparation method of the sulfone-containing macrocyclic siloxane is as follows:
wherein R is1、R2The same meanings as above, and n is 2 to 10.
According to the invention, the sulfone-containing polysiloxane can be prepared into the sulfone-containing polysiloxane fiber through a spinning process. The selectable spinning processes comprise electrostatic spinning, melt spinning, wet spinning, dry and wet spinning and the like, and electrostatic spinning is preferred;
further preferably, the electrostatic spinning conditions comprise that the spinning temperature is 20-50 ℃, the environmental humidity is 20-40%, the spinning voltage is 10-25 kV, the receiving distance is 15-20 cm, and the spinning speed is 0.05-0.5 mm/min; most preferably, the spinning temperature is 30 ℃, the ambient humidity is 20%, the spinning voltage is 18kV, the receiving distance is 15cm, and the spinning speed is 0.05 mm/min.
According to the invention, the sulfone-containing polysiloxane has good degradation cycle performance.
Further, a method for recycling the degradation of sulfone-containing polysiloxanes to give the initial sulfone-containing macrocyclic siloxane monomer, comprising the steps of:
dissolving sulfone-containing polysiloxane with solvent, preferably tetrahydrofuran, adding KHSO4The reaction temperature is 25-100 ℃, preferably 30 ℃, the reaction time is 10-48h, preferably 24h, and the sulfone-containing macrocyclic siloxane monomer is obtained through degradation.
The above reaction route for recycling of degradation to sulfone-containing macrocyclic siloxane monomers is as follows:
the invention has not been described in detail, but is in accordance with the state of the art.
The invention has the following beneficial effects:
1. according to the invention, sulfone groups with relatively high polarity are introduced into the siloxane chain segment, so that the properties of the main chain of the siloxane chain segment are changed, and further, the crystallinity and intermolecular action of polysiloxane are improved, thus the spinnability of the polymer is improved, novel organic silicon fibers are prepared, and the problem that the existing siloxane is difficult to spin is solved.
2. The sulfone-containing polysiloxane prepared by the invention is easy to spin, has good thermal stability, and is simple and efficient in synthetic route.
3. The sulfone-containing polysiloxane can be degraded and recycled, and the utilization rate of raw materials is greatly improved.
4. The raw materials of the invention are cheap and easy to obtain, the synthetic method has simple route, and the production process has no pollution.
Detailed Description
The present invention will now be described in further detail by way of specific examples, which are provided for illustration purposes and are not intended to limit the scope of the invention, in conjunction with the following drawings.
Example 1
(1) 8.6g (50mmol) of α, α' -dimercaptop-xylene, 9.2g (50mmol) of a vinyl-bis-head, and 0.2g of benzoin dimethyl ether (DMPA) were added to the round-bottom flask. After sealing, the mixture was placed under an ultraviolet lamp and stirred for reaction for 15min, and the system became viscous to obtain a crude product as a yellow viscous liquid. After drying under vacuum, a yellowish, transparent viscous liquid was obtained with a yield of 16.3g and a yield of 92%. 16.3g (46mmol) of the above viscous liquid was weighed and dissolved in a flask with tetrahydrofuran. Then, 14.1g (46mmol) of the oxidizing agent oxone was added thereto, and the reaction was stirred at room temperature for 12 hours under a nitrogen atmosphere. Thereafter, 14.1g (46mmol) of oxone was added to the system, and the reaction was stirred at room temperature for further 12 hours. After completion of the reaction, white plate-like crystals of P1OX were obtained in a yield of 8.3g and a yield of 55%.
The result of the nuclear magnetic resonance hydrogen spectrum test of the product is shown in figure 1, and as can be seen from figure 1, the corresponding attribution can be found in each peak, which indicates that the sulfone-containing macrocyclic siloxane monomer is successfully synthesized.
(2) Sulfone-containing macrocyclic siloxane monomer (2.9g, 7mmol) was dissolved in a three-necked flask containing anhydrous dimethylsulfoxide, followed by addition of KOH (39.0mg, 0.7mmol), reaction at 100 ℃ for 8h under nitrogen protection, followed by addition of benzoic acid (85.0mg, 0.7mmol) to quench the reaction and remove dimethylsulfoxide to give sulfone-containing polysiloxane as a yellow solid in 90% yield. The obtained sulfone-containing polysiloxane is easy to be drawn into fibers due to the introduction of main chain sulfone groups, and the obtained fiber photo is shown in figure 2. Meanwhile, uniform sulfone-containing polysiloxane fibers can be obtained through electrostatic spinning, and a scanning electron microscope of the spun fibers is shown in figure 3, so that the fibers are uniform, smooth in surface and good in spinnability.
The product was subjected to nmr spectroscopy, as shown in fig. 4. As can be seen from FIG. 4, the peaks can find the corresponding assignments, indicating that ring-opening polymerization has occurred to give a sulfone-containing polysiloxane.
The thermogravimetric analysis of the obtained sulfone-containing silicone fiber is shown in fig. 5. As can be seen from FIG. 5, the sulfone-containing silicone fiber of the present invention has good heat resistance, a thermal weight loss temperature of 328 ℃ and a maximum permanent temperature of 382 ℃.
(3) The sulfone-containing polysiloxane (5.3g) obtained above was taken and dissolved in a single-neck flask containing 15ml of tetrahydrofuran, followed by addition of a solution in 15ml of H2KHSO of O4(27.2g, 0.2mol), stirring at 30 ℃ for 24h to give the sulfone-containing macrocyclic siloxane monomer as a white solid in 87% yield. So that the sulfone-containing polysiloxane is successfully degraded and recycled to obtain the sulfone-containing macrocyclic siloxane monomer.
Example 2
(1) 6.1g (50mmol) of butanedithiol, 9.2g (50mmol) of a vinyl-bis-head, and 0.2g of Benzonic acid (DMPA) were charged into a round-bottomed flask. After sealing, the mixture is placed under an ultraviolet lamp and stirred for reaction for 15min, and the system becomes viscous to obtain a crude product which is colorless viscous liquid. After drying under vacuum, a yellowish, transparent viscous liquid was obtained with a yield of 14.3g and a yield of 94%. 14.1g (46mmol) of the above viscous liquid was weighed and dissolved in a flask with tetrahydrofuran. Then, 14.1g (46mmol) of the oxidizing agent oxone was added thereto, and the reaction was stirred at room temperature for 12 hours under a nitrogen atmosphere. Thereafter, 14.1g (46mmol) of oxone was added to the system, and the reaction was stirred at room temperature for 12 hours. After completion of the reaction, white plate-like crystals of P2OX were obtained in 51% yield.
(2) Sulfone-containing macrocyclic siloxane monomer (2.6g, 7mmol) was dissolved in a three-necked flask containing anhydrous dimethylsulfoxide, followed by addition of KOH (39.0mg, 0.7mmol), reaction at 100 ℃ for 8h under nitrogen, followed by addition of benzoic acid (85.0mg, 0.7mmol) to quench the reaction and remove dimethylsulfoxide to give sulfone-containing polysiloxane as a yellow solid in 93% yield.
(3) GetThe sulfone-containing polysiloxane (4.7g) obtained above was dissolved in a single-neck flask containing 15ml of tetrahydrofuran, and then dissolved in 15ml of H2KHSO of O4(27.2g, 0.2mol), stirring at 30 ℃ for 24h to give a white crystalline sulfone-containing macrocyclic siloxane in 87% yield.
Example 3
(1) 12.5g (50mmol) of 4', 4-dimercaptodiphenylsulfide, 9.2g (50mmol) of a vinyl-bis-head, and 0.2g of benzoin dicarboxylic acid (DMPA) were charged into a round-bottomed flask. After sealing, the mixture was placed under an ultraviolet lamp and stirred for reaction for 15min, and the system became viscous to obtain a crude product as a yellow viscous liquid. After drying under vacuum, a yellowish, transparent viscous liquid was obtained with a yield of 19.5g and a yield of 91%. 20.0g (46mmol) of the above viscous liquid was weighed and dissolved in a flask with tetrahydrofuran. Then, 21.1g (69mmol) of the oxidizing agent oxone was added thereto, and the reaction was stirred at room temperature for 12 hours under a nitrogen atmosphere. Thereafter, 21.1g (69mmol) of oxone was added to the system, and the reaction was further stirred at room temperature for 12 hours. After completion of the reaction, white flaky crystals were obtained in 55% yield.
(2) Sulfone-containing macrocyclic siloxane monomer (3.5g, 7mmol) was dissolved in a three-necked flask containing anhydrous dimethylsulfoxide, followed by addition of KOH (39.0mg, 0.7mmol), reaction at 100 ℃ for 8h under nitrogen, followed by addition of benzoic acid (85.0mg, 0.7mmol) to quench the reaction and remove dimethylsulfoxide to give sulfone-containing polysiloxane as a yellow solid in 89% yield.
(3) The sulfone-containing polysiloxane (6.3g) obtained above was taken and dissolved in a single-neck flask containing 15ml of tetrahydrofuran, followed by addition of a solution in 15ml of H2KHSO of O4(27.2g, 0.5mol), stirring at 30 ℃ for 24h to give the sulfone-containing macrocyclic siloxane as a white solid in 85% yield.
Comparative example 1
According to patent CN101838863B, alpha, beta-dimethoxy polydimethylsiloxane with weight-average molecular weight of about 50 ten thousand is dissolved in toluene and mixed with aminopropyl triethoxysilane, and then the mixture is subjected to polycondensation reaction at 140 ℃ for 3 hours, and the product is electrospun, so that the solidification is easy, the fiber is easy to deform and break, and the re-dissolution spinning cannot be carried out.
Comparative example 2
Reacting octamethylcyclotetrasiloxane under the catalysis of alkali glue at 110 ℃, then heating to 130 ℃ for 30min to inactivate the catalyst to obtain linear polydimethylsiloxane with the weight-average molecular weight of 70 ten thousand, and then carrying out electrostatic spinning on the polysiloxane to find that the polysiloxane has high viscosity, cannot be molded and is easy to break.
Comparative example 3
Uniformly mixing polydimethylsiloxane containing vinyl, oligosiloxane containing silicon-hydrogen bonds and 0.1% chloroplatinic acid catalyst, crosslinking at 150 ℃, and then carrying out electrospinning, wherein fibers are easy to deform and cannot be re-dissolved for spinning.
The above are only preferred embodiments of the present invention and are not intended to limit the present invention. It should be noted that, for those skilled in the art, modifications can be made without departing from the invention, and these modifications should also be construed as the scope of the invention.