Reverse microemulsion process prepares the method for the nano titanium oxide that organises
Technical field
The invention belongs to the inorganic nano-particle field, particularly the reverse microemulsion process preparation nano titanium oxide (TiO that organises
2) method.
Technical background
Nano titanium oxide (nano-TiO
2) except having small-size effect, surface and interface effect, quantum size effect and macro quanta tunnel effect, also have unique colour effect, photocatalysis and the specific function such as ultraviolet shielded, in fields such as automotive industry, makeup, wastewater treatment, purifying airs, application prospect is very widely arranged.
But, large due to the specific surface area of nano titanium oxide, the surface can be high, is in non-thermodynamics steady state, therefore very easily reunite, and also have great amount of hydroxy group from the teeth outwards and present wetting ability, be difficult to be dispersed in organic medium, thereby become the Main Bottleneck of its application.Although, by to n-TiO
2Carry out physical adsorption, coat modification and surface chemical modification, make its surface by inorganic materials or Coated with Organic Matter, can reduce to a certain extent agglomeration, improve the consistency with organic polymer.But these methods normally adopt commercially available nano-TiO
2Carry out modification, need first with nano-TiO
2Reunite preventing with solvent and high speed dispersion, then carry out modification, also have aftertreatment and redispersion process after modification is completed, so complex process, cost is higher.
Summary of the invention
The object of the invention is to overcome existing complex process in nano-titanium dioxide modified and application process, condition and control that difficulty is large, the high in cost of production shortcoming, the method that provides the preparation of a kind of technique is simple and reaction conditions is gentle reverse microemulsion process to organise nano titanium oxide, the prepared nano titanium oxide that organises is dispersed in Reverse Microemulsion System take acrylate monomer as oil phase, can directly be added to the water and carry out pre-emulsification and letex polymerization.
The present invention by the emulsifying effect of cetyl trimethylammonium bromide (CTAB), forms Reverse Microemulsion System in the mixed solution of acrylate monomer (Acr), vinylformic acid and a small amount of deionized water; Then, butyl (tetra) titanate and the silane coupling agent that contains the two keys of alkoxyl group and C=C are added in Reverse Microemulsion System, butyl (tetra) titanate generates nano titanium oxide through hydrolysis, utilize simultaneously the hydroxyl generation condensation reaction on hydroxyl that silane coupling agent hydrolysis generates and nano titanium oxide surface, make the nano titanium oxide that organises.
Purpose of the present invention is achieved through the following technical solutions:
Reverse microemulsion process prepares the method for the nano titanium oxide that organises: at room temperature, in mass fraction, 4-10 part cetyl trimethylammonium bromide (CTAB), 6-14 part vinylformic acid (AA) and 10-30 part acrylate monomer (Acr) are mixed, drip deionized water and make system become clarification, namely get CTAB/AA/Acr/H
2The O Reverse Microemulsion System; 2-6 part butyl (tetra) titanate and 1-4 part silane coupling agent are added CTAB/AA/Acr/H simultaneously
2In the O Reverse Microemulsion System, it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 6-24h, makes the nano titanium oxide that organises; Described acrylate monomer is one or both in methyl methacrylate (MMA), butyl acrylate (BA), vinylbenzene (St); Described silane coupling agent is γ-methacryloxypropyl trimethoxy silane (A-174), vinyltrimethoxy silane (A-171) or vinyltriethoxysilane (A-151).
For further realizing the object of the invention, in mass fraction, described deionized water is preferably 10-20 part.In mass fraction, described butyl (tetra) titanate is preferably 3-5 part.
The present invention is at room temperature, and CTAB, AA and acrylate monomer (Acr) are mixed, and drips deionized water and makes system become clarification, namely gets CTAB/AA/Acr/H
2The O Reverse Microemulsion System; Butyl (tetra) titanate and the silane coupling agent that contains the two keys of alkoxyl group and C=C are added in Reverse Microemulsion System simultaneously, and it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 6-24h, makes the nano titanium oxide that organises.
Reverse microemulsion process of the present invention prepares the method for the nano titanium oxide that organises to be compared with current techniques, has following advantage:
(1) due to take acrylate monomer as dispersion medium, therefore the prepared nano titanium oxide system that organises can directly be carried out pre-emulsification and letex polymerization by adding water, and is easy to use.
(2) when butyl (tetra) titanate hydrolysis generates nano titanium oxide, adopt silane coupling agent directly to its modification, lipophilicity improves, and be conducive to itself and the raising of polymer phase capacitive, and technique is simple, the reaction conditions gentleness.
(3) by " bridge formation " effect of silane coupling agent, introduce the two keys of undersaturated C=C on nano titanium oxide, enlarged its range of application.
Description of drawings
Fig. 1 is the infrared spectrum that reverse microemulsion process prepares the nano titanium oxide that organises.
Fig. 2 is the transmission electron microscope picture that reverse microemulsion process prepares the nano titanium oxide that organises.
Embodiment
The present invention is further illustrated below in conjunction with drawings and Examples, but embodiments of the present invention are not limit so.
Embodiment 1
At room temperature, 6g CTAB, 9g AA and 24g MMA are mixed, more slowly drip the 10g deionized water and make system become clarification, namely get CTAB/AA/MMA/H
2The O Reverse Microemulsion System; 4g butyl (tetra) titanate and 1g A-174 are added in Reverse Microemulsion System simultaneously, and it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 24h, namely gets the nano titanium oxide that organises.
Fig. 1 is the infrared spectrum that the present embodiment reverse microemulsion process prepares the nano titanium oxide that organises.Sample preparation and test procedure: the nano titanium oxide system that will organise joins in aqueous ethanolic solution, (Anting Scientific Instrument Factory, Shanghai in whizzer, 800B) with the centrifugal 30min of the speed of 3500rpm/min, remove free silane coupling agent, CTAB and acrylate monomer, repeated washing 3 times, then be placed in the baking oven of 45 ℃ and dry.Use the pellet technique sample preparation, adopt infrared spectrometer (German Bruker company, Tensor 27) test, wave-number range is 400-4000cm
-1, resolving power is 4cm
-1, scanning times is 16 times.As can be seen from Figure 1,400-900cm
-1The stretching vibration absorption peak that has occurred Ti-O in scope, 3250cm
-1The place is the O-H stretching vibration peak of titanium dioxide surface, 1630cm
-1And 1400cm
-1The place is for being adsorbed in the flexural vibration absorption peak of titanium dioxide surface water, 1500cm
-1And 1430cm
-1The place is CH on remaining Surfactant CTAB
2And CH
3Vibration absorption peak.1725cm
-1The place is the symmetric vibration absorption peak of carbonyl in A-174.At 1170cm
-1Ti-O-Si key stretching vibration peak has appearred in the place, and this shows A-174 after hydrolysis, with TiO
2The hydroxyl generation dehydration reaction of particle surface generates covalent linkage, successfully is grafted to the surface of nano titanium oxide.
Fig. 2 is the transmission electron microscope picture that reverse microemulsion process prepares the nano titanium oxide that organises.Sample preparation and test procedure: approximately 500 times of the nano titanium oxide system that will organise dilute with waters, drip on copper mesh after ultra-sonic dispersion, to do when not dried until it, phospho-wolframic acid dyeing with 1.5wt%, adopt transmission electron microscope (Dutch FEI electron optics company limited, the form of TECNAIG2-12) observing modified nano-titanium dioxide after drying at room temperature.In Fig. 2, the microballoon of black is nano titanium oxide, and median size is in about 10.2nm, and is uniformly dispersed, the agglomeration between particle be improved significantly.
Embodiment 2
At room temperature, 7g CTAB, 7g AA and 30g butyl acrylate (BA) are mixed, more slowly drip the 8g deionized water and make system become clarification, namely get CTAB/AA/BA/H
2The O Reverse Microemulsion System; 6g butyl (tetra) titanate and 3g A-171 are added in Reverse Microemulsion System simultaneously, and it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 6h, namely gets the nano titanium oxide that organises.
Embodiment 3
At room temperature, 8g CTAB, 10g AA and 10g methyl methacrylate, 16g butyl acrylate are mixed, more slowly drip the 12g deionized water and make system become clarification, namely get CTAB/AA/MMA-BA/H
2The O Reverse Microemulsion System; 5g butyl (tetra) titanate and 4g A-151 are added in Reverse Microemulsion System simultaneously, and it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 12h, namely gets the nano titanium oxide that organises.
Embodiment 4
At room temperature, 6g CTAB, 10g AA and 25g methyl methacrylate, 5g vinylbenzene (St) are mixed, more slowly drip the 15g deionized water and make system become clarification, namely get CTAB/AA/MMA-St/H
2The O Reverse Microemulsion System; 3g butyl (tetra) titanate and 2g A-174 are added in Reverse Microemulsion System simultaneously, and it is 0.4-0.6g/min that control adds speed, then at room temperature stirs 24h, namely gets the nano titanium oxide that organises.
Substantially same Fig. 1 of infrared spectrum of the nano titanium oxide that organises of embodiment 2-4 preparation; Substantially same Fig. 2 of transmission electron microscope picture of the nano titanium oxide that organises of preparation, the particle diameter of the nano titanium oxide that organises that each embodiment is prepared is as shown in table 1.As can be seen from Table 1, the particle diameter of nano titanium oxide of organising is in the scope of 9-14.5nm, illustrates by the graft reaction of silane coupling agent at titanium dioxide surface, make surface properties from inorganic become organic, effectively suppressed the generation of agglomeration, system has satisfactory stability.
Table 1
Sample |
Embodiment 1 |
Embodiment 2 |
Embodiment 3 |
Embodiment 4 |
Particle diameter (nm) |
10.2 |
12 |
9 |
14.5 |