CN1089077C - Surficial modification process for SiO2 sol particles - Google Patents

Abstract

A method for surface modification of silica sol colloidal particles, the method uses a sol-gel method to directly prepare _SiO2 sols with different spatial conformations by modifying the surface of _SiO2 sol colloidal particles with organic macromolecules. Nature prepares the necessary conditions. The method has simple process and convenient operation.

Description

A method for surface modification of silica sol colloidal particles

The invention belongs to a method for modifying sol particles, in particular to a method for modifying the surface of _SiO2 sol particles.

The rapid development of modern science and technology has brought many new development opportunities to the field of materials. From the perspective of performance and requirements, realizing structure control at the nanometer level is the research trend of nanosynthesis technology in recent years. Utilizing the existing conformation of organic macromolecules in solution, modifying the sol network structure by modifying the surface of SiO ₂ sol nanocolloids is a necessary condition for the realization of structure-controllable nanomaterial synthesis technology. At present, there are many preparation methods of SiO ₂ nanomaterials reported, but most of them involve controllable powder structure, but there are very few reports on the control of SiO ₂ sol network structure. Chinese invention patent 1145331 relates to the preparation technology of amorphous nano-SiO ₂ with controllable particle size under the modulation of surfactant; the sol structure has not been studied, and Chinese invention patent 1150124 reports a sol colloidal particle The surface modification technology is characterized in that the metal-ceramic composite film can be prepared by modifying the metal active components. It can be seen that the above method only involves the modification and preparation technology of the powder, and almost does not involve the regulation of the SiO ₂ sol network structure.

The purpose of the present invention is to provide a method for modifying the surface of colloidal sol particles which can adjust the network structure of _SiO2 solution.

The invention adopts a sol-gel method to directly prepare SiO ₂ sol network structures with different spatial conformations by modifying the surface of SiO ₂ sol colloid particles with organic macromolecules.

The present invention comprises the steps:

1. Add ethyl orthosilicate to half of the total amount of ethanol solution, and stir to form solution (I);

2. Add quantitative water, ammonia water and additives to the other half of the total amount of ethanol solution, and mix well to form solution (II);

3. During the stirring process, slowly add the solution (II) into the solution (I), continue to stir for 30 minutes, then transfer the mixed solution into a polytetrafluoroethylene sealed valve container, and age at a constant temperature to obtain different SiO ₂ sol with spatial conformational network structure;

It is characterized in that the proportioning (molar ratio) of sol is as follows:

Ethanol: water: additive: ammonia water: tetraethyl orthosilicate=

(10-100):(0.5-10):(0.01-0.1):(1.0×10 ^-5 ):1;

As mentioned above, the aging temperature is 20-260°C, and the aging time is 0.5 days-1 year.

The additives mentioned above can be polyethylene glycol (PEG), fatty alcohol polyoxyethylene ether (AEO), fatty alcohol polyoxyethylene polyoxypropylene ether copolymer (PEO-PPO-PEO).

Compared with the prior art, the present invention has the following advantages:

The method is simple in process, easy to operate, and easy to obtain raw materials. SiO _sols with various spatial conformations can be prepared by one-step method, and the SiO _sols obtained by adding polyethylene glycol (PEC) have a ring network structure. The _SiO2 sol obtained by fatty alcohol polyoxyethylene ether (AEO) has a rod-like network structure, and the _SiO2 sol obtained by adding fatty alcohol polyoxyethylene polyoxypropylene ether copolymer (PEO-PPO-PEO) has a dendritic network structure . The necessary conditions are prepared for the next step of regulating the channel properties of SiO ₂ nanomaterials and improving the surface properties.

Example 1

Dissolve 20ml of tetraethyl orthosilicate in 100ml of absolute ethanol and stir for 15 minutes; mix 3.2ml of H ₂ O, 110ml of absolute ethanol, 0.1ml of 6M NH ₃ H ₂ O and 0.1ml of PEG200. Mix the above two sols evenly, then put them into a Teflon airtight container and age them at 20°C for 150 days or at 60°C for 20 days to prepare the SiO ₂ sol with ring network structure.

Example 2

In the above-mentioned Example 1, 5ml of PEG200 or PEG600 can also be added, and under the same conditions, a SiO ₂ sol with a ring network structure can be prepared.

Example 3

In the above-mentioned Example 1, 10ml of PEG200 or PEG600 can also be added, and under the same conditions, a SiO ₂ sol with a ring network structure can be prepared.

Example 4

In the above-mentioned Example 1, 0.1 ml of AEO with a degree of polymerization of 3 or AEO with a degree of polymerization of 15 can also be added to prepare a SiO ₂ sol with a rod-like network structure under the same conditions.

Example 5

In the above-mentioned Example 1, 5 ml of AEO with a degree of polymerization of 3 or AEO with a degree of polymerization of 15 can also be added, and under the same conditions, a SiO ₂ sol with a rod-like network structure can be prepared.

Example 6

In the above-mentioned Example 1, 10 ml of AEO with a degree of polymerization of 3 or AEO with a degree of polymerization of 15 can also be added, and under the same conditions, a SiO ₂ sol with a rod-like network structure can be prepared.

Example 7

In the above example 1, 0.1ml of copolymer (PEO) ₃ -(PPO) ₃₀ -(PEO) ₃ or copolymer (PEO) _{4 -} (PPO) ₃₉ -(PEO) ₄ can also be added, under the same conditions, A SiO ₂ sol with a dendritic network structure was prepared.

Example 8

In the above example 1, 5ml of copolymer (PEO) ₃ -(PPO) ₃₀ -(PEO) ₃ or copolymer (PEO) ₄ -(PPO) ₈₉ -(PEO) ₄ can also be added, and under the same conditions, the preparation A SiO ₂ sol with a dendritic network structure was produced.

Example 9

In the above example 1, 10ml of copolymer (PEO) ₃ -(PPO) ₃₀ -(PEO) ₃ or copolymer (PEO) ₄ -(PPO) ₃₉ -(PEO) ₄ can also be added, and under the same conditions, the preparation A SiO ₂ sol with a dendritic network structure was produced.

Claims (2)

1. a surficial modification process for SiO 2 sol particles comprises the steps:

(1) add tetraethoxy in half of the total consumption of ethanolic soln, the back that stirs forms solution (I);

(2) quantitative water, ammoniacal liquor and additive are added in second half of the total consumption of ethanolic soln, mix the back and form solution (II);

(3) in whipping process, solution (II) is slowly added in the solution (I), continue to stir 30 minutes, then mixed solution is changed in the encloses container of tetrafluoroethylene, under 20-260 ℃ of ageing temperature, ageing 0.5 day-1 year, the SiO that promptly obtains having different spaces conformation network structure ₂Colloidal sol;

The proportioning (mol ratio) that it is characterized in that colloidal sol is as follows:

Ethanol: water: additive: ammoniacal liquor: tetraethoxy=

(10-100)∶(0.5-10)∶(0.01-0.1)∶1.0×10 ^-5∶1。

2. a kind of surficial modification process for SiO 2 sol particles according to claim 1 is characterized in that described additive is polyoxyethylene glycol, Fatty Alcohol(C12-C14 and C12-C18) oxygen Vinyl Ether, aliphatic alcohol polyethenoxy polyoxypropylene ether copolymer.