Background technology
Composite organic-inorganic material is at present and a focus in the investigation of materials in the future, compares with traditional matrix material, and they have some very particular performances, therefore more and more are subjected to paying attention to widely.They had both had the performance (as flexibility, ductility, dielectricity and workability etc.) of organic polymer material, had the performance (as rigidity, high thermal stability etc.) of inorganic materials again.Particularly organic-inorganic nanocomposite because the adding of nanoparticle makes matrix material have some special performances toward contact, has purposes more widely.Wherein SiO 2-polymer composite material is to report composite organic-inorganic material the most widely at present.
The main at present method that adopts mechanical blending of method for preparing SiO 2-polymer composite material, earlier silicon-dioxide is made a certain size solid particulate, after carrying out surface treatment as required, adopt the method for fusion or solution blending, mix with polymkeric substance.This method is used to prepare particle diameter big (micron order) and during silica-filled amount less (generally<30%), it is simple to have method, lower-cost advantage.But, owing to have organic and inorganic two-phase all the time in the system, so the dispersion of silicon-dioxide in polymkeric substance is difficult to accomplish very even.And when if the content of inorganic phase is higher, the viscosity of system sharply increases, and causes processing difficulties.
In addition, because the surface-area of nanoparticle is very big, exist very big gathering tendency, the method with mechanical blending is difficult to avoid the reunion of particle in polymkeric substance.Simultaneously the manufacturing cost of nano-silicon dioxide particle also will be far above common micron silica particle, thus the method for mechanical blending when preparation nanometer grade silica-polymer composites particularly some system that inorganic phase particle diameter and dispersed homogeneous degree are had relatively high expectations certain limitation is arranged.
Sol-gel technique is a kind of important method of the preparation organic-inorganic nanocomposite that gets up of developed recently, it utilizes the hydrolysis of metal alkoxide compound and polycondensation to combine with the polyreaction of polymkeric substance, control the sol-gel process by control hydrolysis-polycondensation, to obtain the inorganic phase of nanoscale.Because it can carry out under relatively mild condition, and in the matrix material that makes inorganic particulate be evenly distributed and size less, therefore over nearly 20 years significant progress is being arranged.
Prepare SiO 2-polymer composite material with sol-gel method, the at present main alkoxide that uses silicon or halogenide are as tetraethoxysilane (TEOS), tetramethoxy-silicane (TMOS), chlorosilane or the like.But because the alkoxide and the halid cost of silicon are higher, this method also is difficult to be applied to large-scale industrial production.And because the hydrolysis of silane oxide needs a certain amount of water to participate in reaction, and need small amount of acid as catalyzer.With the mixing process of polymkeric substance in always be difficult to accomplish complete hydrolysis, always residual in the system have a unhydrolysed silane oxide of part, the water that exists in the system also may bring disadvantageous effect to the performance of the finished product simultaneously.
The objective of the invention is to use the active silicic acid that from the Industrial products water glass of cheapness or water glass, extracts to replace silane oxycompound or halid hydrolysate to prepare SiO 2-polymer composite material, to reduce cost, and water-content is few in the system, help improving the finished product performance, system viscosity is little, be convenient to prepare the matrix material of high inorganic phase content, process is simpler, is fit to suitability for industrialized production.Compare with the mechanical blending method, generated in-situ silicon dioxide granule size is little and be easy to control, distributes and more becomes evenly, more is applicable to the preparation nano composite material.
Summary of the invention
The objective of the invention is to study the preparation method of a kind of low cost, high performance SiO 2-polymer composite material.
The objective of the invention is to study a kind of preparation method who is applicable to nano silicon-polymer composites.
The objective of the invention is to study that a kind of method is simple, the preparation method of the SiO 2-polymer composite material of high silicon dioxide content.
Preparation method of the present invention makes by three-procedure.The first step is adjusted to acidity with sour pH value with water glass or sodium silicate solution, adds the saturated water of salt, with organic solvent extraction active silicic acid wherein; Second step joined the active silicic acid solution that obtains carries out polymerization in monomer or the prepolymer, perhaps directly add the solution of polymkeric substance, mixes; The 3rd step was aftertreatment, with solvent removal in the system and recovery, the mixing solutions that obtains was heat-treated at 60-380 ℃, made silicic acid dehydration polycondensation, became silicon-dioxide, but can not make polymer unwinds, thereby obtain SiO 2-polymer composite material.
By the solid content of thermogravimetry mensuration active silicic acid solution, this solid content represents that with the silica volume in the solution content of silicon-dioxide promptly adds the solid content in the active silicic acid solution in the matrix material.
Used acid can be mineral acid or organic acid in the above-mentioned preparation process, example hydrochloric acid, and sulfuric acid and phosphoric acid or acetic acid etc., the pH scope is generally at 1-5.Used inorganic salts is NaCl, NaSO
4, Na
2CO
3, Na
2HPO
4Or solvability such as KCl salt preferably.Used organic solvent such as tetrahydrofuran (THF), dioxane, the 2-propyl alcohol, solvabilities such as the trimethyl carbinol and N-N-methyl-2-2-pyrrolidone N-are solvent or their mixture preferably.
The present invention be applicable to can be in organic solvent dissolved monomer, prepolymer or polymkeric substance, the homopolymer of the derivative of polystyrene, polyacrylic acid, polymethacrylate, polyvinyl acetate (PVA) or the like or monomer whose or multipolymer all can be used as the raw material of polymkeric substance of the present invention generally speaking.Must not phase-splitting during the solvent of the solvent of dissolved monomer, prepolymer or polymkeric substance and lytic activity silicic acid.
The active silicic acid that the first step reaction of the present invention obtains can add a certain amount of coupling agent when adding monomer or prepolymer or polymers soln and mix, strengthen the bonding force of silicon-dioxide and polymer interface, make the dispersion of silicon-dioxide in polymkeric substance more even, particle diameter is littler.Also can adopt contain polymerizable groups such as two keys coupling agent earlier with monomer or prepolymer polymerization, or with the coupling agent that contains the group that can react with polymkeric substance first with polymer reaction after mix with active silicic acid solution again.Coupling agent is for example: γ-glycidyl ether Trimethoxy silane, Trimethoxy silane base propyl methyl acid esters or the like.
The general structure of the used coupling agent of the present invention is YRSiX
3, X is a bonded hydrolysable group on the Siliciumatom in the formula, as alkoxyl group, and chloro base, acetoxyl group etc.; Y is the active function groups that avidity or response capacity are arranged with polymer molecule, as amino, and sulfydryl, vinyl, epoxy group(ing), the rare acyloxy of methyl-prop etc.; R is other aliphatics or aromatic group.
Add other inorganic particulate colloidal sol when adding monomer or prepolymer or polymers soln in the active silicic acid solution, mix.Inorganic particulate colloidal sol is as titanium colloidal sol, aluminium colloidal sol, zirconium colloidal sol etc.
Be uniformly dispersed in polymkeric substance because the silicon-dioxide of the inventive method etc. are inorganic, particle diameter is controlled easily, therefore can obtain the matrix material that silica weight accounts for the high inorganic phase content of material gross weight 0.1-99.5%, obtain to have the SiO 2-polymer composite material of special performance.
The particle size range of silicon dioxide granule can be controlled between the 0.005-20 micron among the present invention.The silicon-dioxide particle diameter can be regulated by silica volume or coupling dosage, and general silica volume is few, and particle diameter is little, otherwise particle diameter is big; The coupling agent consumption is many, and particle diameter is little, otherwise particle diameter is big.
The size of inorganic phase reaches nano level in the SiO 2-polymer composite material, and its performance will be more satisfactory.The present invention is by regulating silica volume at 0.1-70%, or coupling dosage is between 0.5-99%, or thermal treatment temp is between 60-380 ℃, and the particle diameter that makes silicon dioxide granule in the matrix material is the nanoparticle scope between the 0.005-0.5 micron substantially.
The modulus of the water glass that the present invention selects for use is 2~6.Experimental results show that respond well.
The modulus of the better water glass of the present invention is 3-5.
Select hydrochloric acid for use, water glass regulated by organic acids such as mineral acid such as sulfuric acid and phosphoric acid or acetic acid, Phenylsulfonic acid, tosic acid or sodium silicate solution to acidity is not only convenient but also inexpensive.
Organic solvent is a tetrahydrofuran (THF), dioxane, Virahol, the trimethyl carbinol or N-N-methyl-2-2-pyrrolidone N-or mixed solvent.
Optimum in the above-mentioned organic solvent with tetrahydrofuran (THF), dioxane.
Salt is an inorganic salts, with NaCl, Na
2SO
4, Na
2CO
3, Na
2HPO
4, KCl or their mixing salt etc. be optimum, these saline sources are extensive, and good solvability is arranged in water.
The used monomer of the present invention is can be dissolved in tetrahydrofuran (THF), dioxane, Virahol, the trimethyl carbinol, N-N-methyl-2-2-pyrrolidone N-, dimethyl sulfoxide (DMSO), best in N,N-DIMETHYLACETAMIDE or their mixed solvent, this class monomer is as vinylbenzene and substituent thereof, vinylformic acid and substituent thereof, acrylate and substituent thereof, methacrylic acid and substituent thereof, methacrylic ester and substituent thereof, vinyl acetate, caprolactone, hydroxyalkanoate, hexanolactam etc.;
Prepolymer among the present invention is can be dissolved in tetrahydrofuran (THF), dioxane, Virahol, the trimethyl carbinol, N-N-methyl-2-2-pyrrolidone N-, dimethyl sulfoxide (DMSO), N,N-DIMETHYLACETAMIDE they or mixed solvent in best, this class prepolymer is as polyamic acid, Resins, epoxy and solidifying agent, polyethers or polyester polyol and polyisocyanates, benzoxazine etc.;
Polymkeric substance among the present invention is can be dissolved in tetrahydrofuran (THF), dioxane, Virahol, the trimethyl carbinol or N-N-methyl-2-2-pyrrolidone N-, dimethyl sulfoxide (DMSO), best in N,N-DIMETHYLACETAMIDE or their mixed solvent, this base polymer is as polystyrene and substituent thereof, polyacrylic acid and substituent thereof, polyacrylic ester and substituent thereof, polymethyl acrylic acid and substituent thereof, polymethacrylate and substituent thereof, vinylbenzene, vinylformic acid, methacrylic acid and ester derivative thereof, the multipolymer of two or more component in the components such as maleic anhydride, polyvinyl acetate (PVA), polythene-ethenol multipolymer, polycaprolactone, poly (hydroxyalkanoate) esters polymer and multipolymer such as polylactide and poly-glycollide and their multipolymer, the multipolymer of caprolactone and hydroxyalkanoate and polymeric amide or the like.
The present invention extracts active silicic acid and prepares SiO 2-polymer composite material from the Industrial products water glass of cheapness and water glass, compare with the method that prior art adopts silica dioxide granule directly to add polymeric system, inorganic dispersion in matrix material is more even, phase size is littler, is convenient to prepare nano silicon-polymer composites; Compare with the existing sol-gel method of silane hydrolyzate that adopts, cost descends a lot, and water-content is few in the system, and is less to the product property influence.The present invention can control the particle diameter of silicon-dioxide effectively, therefore can obtain nano level SiO 2-polymer composite material easily.Simultaneously the same with common sol-gel method, can also add other inorganic sol, preparation multi-element, inorganic/polymer composites.Because system viscosity is little in the preparation process, the inventive method can be prepared the matrix material of high inorganic phase content, make material possess unique composite performance, as good thermotolerance, wear resistance, mechanical property and low thermal expansivity, and it can keep the transparency of polymer body, according to silicon-dioxide and the quantity of other inorganic sol adding and the selection of coupling agent, can regulate the refractive index of matrix material easily, be applicable to make have heatproof, the optical material of property such as wear-resisting and high refractive index or the top coat of optical material; Because of inorganic the combination with polymkeric substance well, therefore can be used as the structured material of property again, be applied to hot environment.
Embodiment
Embodiment 1
The water glass solution of 30ml3.2mol/l slowly is added drop-wise to the H of 30ml1mol/l
2SO
4The middle adjusting about pH value to 3 adds the NaCl of 10g and the active silicic acid in the 40ml tetrahydrofuran (THF) aqueous phase extracted.The tetrahydrofuran (THF) layer is told the tetrahydrofuran solution that obtains active silicic acid.Recording its solid content (representing with silica weight concentration) by thermogravimetry is 13%.
The tetrahydrofuran solution that takes by weighing the active silicic acid of 1.2 grams joins in the 10%DMAC solution of 100 gram polyamic acids, and at room temperature violent stirring made it abundant reaction in 3.5 hours.Then reaction product at sheet glass top-pour film, respectively handled 2 hours at 60,100,200 and 300 ℃ respectively, obtain Polyimide, the particle diameter of inorganic phase is between the 30-100 nanometer in the material.The transparency of material with do not add before the silicon-dioxide the same.By thermogravimetic analysis (TGA), the inorganic phase content that records in the material is 1.1%.The heat decomposition temperature of material does not improve 8 ℃ before adding silicon-dioxide.Embodiment 2
The tetrahydrofuran solution that takes by weighing the active silicic acid among the 30 gram embodiment 1 joins in the 10%DMAC solution of 100 gram polyamic acids, adds 1.5 gram γ-glycidyl ether Trimethoxy silanes again, and at room temperature violent stirring made it abundant reaction in 5 hours.Then reaction product is watered film, respectively handled 2 hours at 60,120,200 and 300 ℃ respectively.Obtain the polyimide/silicon dioxide nano composite material.By transmission electron microscope observation, inorganic phase particle diameter is less than 100 nanometers in the material.By thermogravimetic analysis (TGA), the inorganic phase content that records in the material is 35%.The material coefficient of thermal expansion coefficient is reduced to half of not adding before the silicon-dioxide.
Embodiment 3
The tetrahydrofuran solution that takes by weighing the active silicic acid among the 22 gram embodiment 1 joins in 10% tetrahydrofuran solution of 50 gram polystyrene, at room temperature stirs to make it in 3 hours fully to react to mix.Then gained solution is under agitation added in the 500 gram methyl alcohol and precipitate, sedimentation and filtration is come out, vacuum-drying is 4 hours under 50 ℃ of 100Pa conditions, respectively handles obtaining the silicon dioxide-poly-benzene composite material in 2 hours more respectively at 60,100,140,180 ℃.With the section of scanning electron microscopic observation material, find that inorganic phase particle diameter is about the 0.9-3 micron.The shock strength of material does not improve 20% before adding silicon dioxide granule, heat decomposition temperature improves 20 ℃.
Embodiment 4
The tetrahydrofuran solution that takes by weighing the active silicic acid among the 65 gram embodiment 1 joins in 10% tetrahydrofuran solution of 30 gram polystyrene-maleic anhydride multipolymers, at room temperature stirs and makes it abundant reaction in 6 hours.Then reaction product is watered film, after at room temperature drying, respectively handled 2 hours at 60,100,140,180 ℃ respectively again.Obtain the matrix material of silicon dioxide-poly-(phenylethylene-maleic anhydride) multipolymer.Thermogravimetry records that inorganic phase content is 80% in the material.This material can be used for polystyrene blend to improve the dispersiveness of silicon-dioxide in polymkeric substance.
Embodiment 5
The tetrahydrofuran solution that takes by weighing the active silicic acid among the 10 gram embodiment 1 joins in 100 milliliters of tetrahydrofuran solutions that are dissolved with 13 gram polymethylmethacrylate-9: 1 multipolymers of Trimethoxy silane base propyl methyl acid esters mol ratio, stirs under the room temperature.Then reaction product is poured in the mould, placed under the room temperature and make solvent evaporates, handled 3 hours at 120 ℃ then, obtain nano silicon and strengthen polymethyl methacrylate materials.Material appearance is a water white transparency, the section of scanning electron microscopic observation material, and visible inorganic phase particle diameter is less than 100 nanometers.Material impact intensity and compressive strength all improve more than 50% before not adding silicon-dioxide.Embodiment 6
The tetrahydrofuran solution that takes by weighing the active silicic acid among the 10 gram embodiment 1 joins in the methyl methacrylate tetrahydrofuran solution of 50ml15%, in above-mentioned solution, add 1.2g Trimethoxy silane base propyl methyl acid esters and 0.8g initiator A IBN, stir.
Get 1g butyl (tetra) titanate (Ti (OBu)
4), 0.1g acetic acid and 10ml Virahol stir, and mix, airtight leave standstill 3 days after, obtain transparent faint yellow titanium colloidal sol.
Above-mentioned active silicic acid/monomer/coupling agent/initiator solution and titanium colloidal sol are poured in the 100ml three-necked bottle, and vigorous stirring 2 hours after mixing, connects reflux condensing tube, is warming up to 70 ℃ under nitrogen protection, reacts 5 hours, obtains heavy-gravity solution.This solution is coated the plastic optics lens surface with spin-coating method, and respectively at 60 ℃, 80 ℃ and 120 ℃ of thermal treatment 2 hours can obtain transparent wear-resistant coating, and the pure PMMA of hardness ratio improves 2 times.The specific refractory power of coating can change to adapt to different types of glass lens by regulating silicon/titanium biphase ratio.
Embodiment illustrated and that discuss is only used for demonstrating use known for inventor best mode of the present invention to those skilled in the art in this specification sheets.Any content in the specification sheets all can not be thought limiting the scope of the invention.Can make amendment and do not exceed scope of the present invention above embodiment, by above explanation, this be conspicuous for those skilled in the art.Therefore it should be understood that in the scope of claims and equivalent thereof, can implement the present invention in the mode different with above specific descriptions.