CN102061618B - A method for grafting mesoporous silica gel on fiber by calcium ion crosslinking - Google Patents

Abstract

The invention provides a method for grafting mesoporous silica gel on a fiber through calcium ion crosslinking. A preparation method comprises the following steps of: grafting polyacrylic acid on the fiber through ultraviolet radiation, taking out and washing a homopolymer on the surface of the fiber, and carrying out neutralization processing with sodium hydroxide to obtain the fiber grafted with polyacrylate sodium; preparing a sodium-silicate aqueous solution; soaking the fiber grafted with the polyacrylate sodium into the sodium-silicate aqueous solution, taking out the fiber, absorbing the adhered excessive solution through water-absorbing paper, and immediately placing the fiber into a calcium-chloride aqueous solution for crosslinking to obtain calcium silicate grafted on the fiber; and obtaining a mesoporous silica-gel layer with abundant Si-OH functional groups on the surface of the calcium silicate through the processing of hydrochloric acid solutions with different pH values so as to obtain the fiber grafted with the mesoporous silica gel. The method disclosed by the invention is simple in operation, does not use any organic solvent, and can be used in the fields of organic-substance adsorption and separation, controlled medicament release, organizational projects, catalysis and the like.

Description

A method for grafting mesoporous silica gel on fiber by calcium ion crosslinking

technical field

The invention relates to a method for preparing mesoporous silica gel grafted on fiber by calcium ion crosslinking, belonging to the field of functional materials.

Background technique

Fiber material has good flexibility and mechanical strength, large specific surface area, can be prepared into various shapes, and is easy to use. But the materials that can be spun into fibers are very limited, and the formed fibers often lack various functionalities.

Silica gel is a highly active adsorption material, and its chemical formula is mSiO ₂ ·nH ₂ O. Insoluble in water and any solvent, non-toxic and tasteless, stable in chemical properties, does not react with any substance except strong alkali and hydrofluoric acid. Various types of silica gel form different pore structures due to their different manufacturing methods. The chemical composition and physical structure of silica gel determine that it has many characteristics that other similar materials cannot replace: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength. Mesoporous silica gel prepared with various surfactants and ionic liquids as templates has been widely used in catalysis, adsorption separation, molecular sieve and other fields. Various functions, such as catalytic performance and antibacterial performance, can be obtained by adding other inorganic components to silica gel.

Traditional silica gel materials are prepared by hydrolysis and polycondensation of organosilanes such as tetraethyl silicate. The reaction time is too long, and various acid-base catalysts often need to be added, which is not conducive to the application in the biomedical field.

The introduction of specific substances on the material matrix through graft polymerization is an effective means to achieve material modification. In this way, the original physical and mechanical properties of the material can be maintained, and various functions can be flexibly obtained. If the mesoporous silica gel layer is grafted onto the fiber by grafting, the good flexibility of the fiber material can be combined with the advantages of high adsorption performance of silica gel, good thermal stability, and stable chemical properties. At present, there are few reports on grafting silica gel to fiber materials. Niu Mei et al. used UV irradiation to modify the surface of natural wool fibers, and grafted silver-loaded nano-silica antibacterial agents on wool by chemical grafting to prepare antibacterial wool fibers [Preparation of antibacterial wool fibers and Its structure and performance research, doctoral dissertation of Taiyuan University of Technology, 2009.4].

Calcium silicate has excellent mechanical properties, and as one of the third-generation biomaterials, it has attracted the attention of researchers in recent years [Biomaterials, 2008, 29: 2588-2596]. Through hydrochloric acid treatment, a silica gel layer with abundant Si-OH functional groups can be obtained on the surface of calcium silicate, and the pH value of the solution can be controlled to obtain mesoporous silica gel structures with different pore sizes [Acta Biomaterialia, 2009, 5: 1686-1696]. After treatment under the condition of pH=0.5, the adsorption amount of lysozyme on the surface of silica gel reached 195 mg/g, which was 4.5 times of the protein adsorption amount before acid treatment.

This patent adopts the method of ultraviolet radiation to graft sodium polyacrylate on the surface of the fiber first, and then uses the method of calcium ion cross-linking to graft calcium silicate on the fiber. After being treated with hydrochloric acid solutions with different pH values, the surface has mesoporous silica gel. layer of grafted fibers. This has not seen relevant reports at home and abroad.

Contents of the invention

Aiming at the deficiencies of the prior art, the technical problems to be solved by the present invention are the complex process of fiber grafting to silica gel, difficulty in controlling the grafting rate, limited choice of fibers and the like.

The technical solution of the present invention to solve the technical problems of complex fiber grafting silica gel process, difficult control of grafting rate, and limited choice of fibers is to design a method for grafting mesoporous silica gel on fibers by calcium ion cross-linking.

The invention provides a method for grafting mesoporous silica gel on fibers by calcium ion crosslinking, which is characterized in that the preparation steps are as follows:

a) Refer to patent 200910228776.8 to prepare fibers grafted with polyacrylic acid, put the fibers into an aqueous solution of acrylic acid (AA) with a volume percentage of 10%-50%, and add a polymerization inhibitor ferrous ammonium sulfate with a mass percentage of 0.5-3%, Introduce nitrogen, irradiate with ultraviolet light for 0.5-1 hour, take out and wash the homopolymer with deionized water, and neutralize it with sodium hydroxide to obtain fibers grafted with sodium polyacrylate;

b) preparing 0.5% to 15% of sodium silicate and 0 to 10% of other inorganic salts reacting with calcium ions, and preparing an aqueous calcium chloride solution with a concentration of 0.5% to 10% by mass;

c) Soak the fibers of the above-mentioned grafted sodium polyacrylate into the sodium silicate mixed aqueous solution prepared in step b) for 0.5 to 2 hours, take it out and drip for 2 to 5 minutes, and use absorbent paper to absorb the excess solution attached, Make the attachment liquid on the surface of the fiber as uniform as possible, immediately put it into the calcium chloride aqueous solution prepared in step b), crosslink for 0.5 to 2 hours, rinse with deionized water for 3 to 5 times, and obtain the fiber of grafted calcium silicate ;

d) Prepare an aqueous solution with a pH value of 0.1-6.5 with hydrochloric acid, soak the grafted calcium silicate fiber obtained in step c) in the prepared aqueous solution with different pH values for 0.5-12 hours, and obtain a mesoporous silica gel layer on the surface grafted fibers.

The present invention is a kind of mesoporous silica gel with calcium ion crosslinking grafted on the fiber, which is realized by making full use of the carboxylate and silicate radicals on the calcium ion crosslinking fiber, and the calcium silicate and the fiber can be combined well. After acid treatment, the surface layer of calcium silicate forms mesoporous silica gel. The fibers can be selected from various substrates such as polypropylene, polyethylene, polytetrafluoroethylene, polyacrylonitrile, and polysulfone, and their forms include monofilament fibers, non-woven fabrics, tows, and hollow fibers.

Various inorganic salts that react with calcium ions, such as sodium carbonate, diammonium hydrogen phosphate, disodium hydrogen phosphate, sodium citrate, sodium oxalate, etc., can be added to the sodium silicate aqueous solution to increase different functions.

The method of the invention is simple to operate, does not use any organic solvent, and thus has high biocompatibility, economy and environmental friendliness. Based on the above characteristics, the calcium ion cross-linked mesoporous silica gel grafted on the fiber of the present invention can be used in the fields of organic matter adsorption and separation, drug controlled release, tissue engineering, catalysis and the like.

Detailed ways

The specific embodiments of the present invention are introduced below, but the present invention is not limited by the embodiments.

Example 1. A kind of calcium ion cross-linked mesoporous silica gel grafted on polypropylene fiber non-woven fabric

Reference patent 200910228776.8 prepares polypropylene fiber non-woven fabric grafted with polyacrylic acid, and after neutralization treatment with sodium hydroxide, obtains polypropylene fiber non-woven fabric grafted with sodium polyacrylate;

Prepare the mixed aqueous solution of 0.5% sodium silicate and 1% sodium carbonate by mass percentage, and prepare the calcium chloride aqueous solution with 0.5% concentration by mass percentage;

Soak the fibers of the above-mentioned grafted sodium polyacrylate into the prepared sodium silicate mixed aqueous solution for 0.5 hours, take it out and drip for 2 minutes, use absorbent paper to absorb the excess solution attached, so that the adhesion liquid on the surface of the fiber is as uniform as possible, Immediately put it into the prepared calcium chloride aqueous solution, cross-link for 2 hours, rinse 3 times with deionized water, and obtain fibers of grafted calcium silicate;

Prepare an aqueous solution with a pH value of 4.5 with hydrochloric acid, soak the obtained grafted calcium silicate fiber in the prepared aqueous solution with different pH values for 12 hours, and obtain a polypropylene fiber nonwoven fabric with a mesoporous silica gel layer on the surface.

Example 2. A calcium ion cross-linked mesoporous silica gel grafted on polypropylene monofilament fibers

Refer to patent 200910228776.8 to prepare polypropylene monofilament fibers grafted with polyacrylic acid, and neutralize them with sodium hydroxide to obtain polypropylene monofilament fibers grafted with sodium polyacrylate;

Prepare a mixed aqueous solution of 0.5% sodium silicate and 1% diammonium hydrogen phosphate by mass percentage, and prepare an aqueous calcium chloride solution with a mass percentage concentration of 0.5%;

Soak the above-mentioned polypropylene monofilament fiber grafted with sodium polyacrylate into the prepared sodium silicate mixed aqueous solution for 0.5 hours, take it out and drip it for 2 minutes, use absorbent paper to absorb the excess solution adhered to make the adhesion of the fiber surface Liquid as uniform as possible, immediately put it into the prepared calcium chloride aqueous solution, crosslink for 2 hours, rinse 3 times with deionized water, to obtain fibers of grafted calcium silicate;

Prepare an aqueous solution with a pH value of 4.5 with hydrochloric acid, soak the obtained grafted calcium silicate fiber in the prepared aqueous solution with different pH values for 12 hours, and obtain a polypropylene monofilament fiber with a mesoporous silica layer on the surface.

Example 3. A kind of calcium ion cross-linked mesoporous silica gel grafted on the polytetrafluoroethylene fiber tow

Reference patent 200910228776.8 prepares polytetrafluoroethylene fiber tow grafted with polyacrylic acid, and neutralizes it with sodium hydroxide to obtain polytetrafluoroethylene fiber tow grafted with sodium polyacrylate;

Prepare a mixed aqueous solution of 1% sodium silicate and 1% sodium oxalate by mass percentage, and prepare an aqueous calcium chloride solution with a mass percentage concentration of 10%;

Soak the fibers of the above-mentioned grafted sodium polyacrylate into the prepared sodium silicate mixed aqueous solution for 0.5 hours, take it out and drip for 2 minutes, use absorbent paper to absorb the excess solution attached, so that the adhesion liquid on the surface of the fiber is as uniform as possible, Immediately put it into the prepared calcium chloride aqueous solution, cross-link for 2 hours, rinse 3 times with deionized water, and obtain fibers of grafted calcium silicate;

Prepare an aqueous solution with a pH value of 2.0 with hydrochloric acid, soak the obtained grafted calcium silicate fiber in the prepared aqueous solution with different pH values for 12 hours, and obtain a polytetrafluoroethylene fiber tow with a mesoporous silica gel layer on the surface.

Example 4. A kind of calcium ion cross-linked mesoporous silica gel grafted on polysulfone hollow fiber membrane

Refer to patent 200910228776.8 to prepare polyacrylic acid-grafted polysulfone hollow fiber membranes and neutralize them with sodium hydroxide to obtain polysulfone hollow fiber membranes grafted with sodium polyacrylate;

The preparation mass percentage is the mixed aqueous solution of 5% sodium silicate and 0.5% sodium citrate, and the preparation mass percentage concentration is the calcium chloride aqueous solution of 10% simultaneously;

Soak the above-mentioned polysulfone hollow fiber membrane grafted with sodium polyacrylate into the prepared sodium silicate mixed aqueous solution for 0.5 hours, take it out and drip for 2 minutes, use absorbent paper to absorb the excess solution adhered to make the adhesion of the fiber surface Liquid as uniform as possible, immediately put it into the prepared calcium chloride aqueous solution, crosslink for 2 hours, rinse 3 times with deionized water, to obtain fibers of grafted calcium silicate;

Prepare an aqueous solution with a pH value of 4.5 with hydrochloric acid, soak the obtained grafted calcium silicate fiber in the prepared aqueous solution with different pH values for 12 hours, and obtain a polysulfone hollow fiber membrane with a mesoporous silica gel layer on the surface.

Claims (6)

1. A calcium ion crosslinked on fiber the method for grafting mesoporous silica gel, it is characterized in that may further comprise the steps:

   A) fiber is put into the acrylic acid aqueous solution that percentage by volume is 10%-50%; Adding mass percent is the polymerization inhibitor iron ammonium sulfate of 0.5-3%; Feed nitrogen,, take out with deionized water and clean homopolymers with ultra violet lamp 0.5-1 hour; After the NaOH neutralisation treatment, obtain the fiber of Sodium Polyacrylate grafting;

   B) the preparation mass percent is other and the inorganic salts that calcium ion reacts of 0.5%～15% sodium metasilicate and 0～10%, prepares mass percent concentration simultaneously and be 0.5%～10% calcium chloride water;

   C) fiber of above-mentioned grafted polyacrylic acid sodium is soaked in the sodium metasilicate mixed aqueous solution of step b) preparation 0.5～2 hour; Take out the back and drip and dropped down 2～5 minutes, inhale with blotting paper and remove the too much solution that adheres to, what make fiber surface adheres to liquid as far as possible evenly; Put it into immediately in the calcium chloride water of step b) preparation; Crosslinked 0.5～2 hour,, obtain the fiber of grafting calcium silicates with deionized water rinsing 3～5 times;

   D) with the aqueous solution of hydrochloric acid allotment pH value at 0.1-6.5, immersion 0.5-12 hour in the aqueous solution of the good different pH values of allotment of the fiber of the grafting calcium silicates that step c) is obtained obtains the graft fibres that the surface has the mesoporous silica gel layer.
2. 2. a kind of calcium ion as claimed in claim 1 crosslinked on fiber the method for grafting mesoporous silica gel, it is characterized in that described fiber comprises polypropylene, polyethylene, polytetrafluoroethylene (PTFE), polyacrylonitrile and polysulfones.
3. 3. a kind of calcium ion as claimed in claim 1 crosslinked on fiber the method for grafting mesoporous silica gel, it is characterized in that described fiber form comprises nonwoven fabric, tow and doughnut.
4. 4. a kind of calcium ion as claimed in claim 1 crosslinked on fiber the method for grafting mesoporous silica gel; It is characterized in that adding in the described sodium metasilicate mixed aqueous solution inorganic salts various and the calcium ion reaction; Said inorganic salts are sodium carbonate, diammonium hydrogen phosphate, sodium hydrogen phosphate, natrium citricum, sodium oxalate; The inorganic salts that add generate insoluble calcium phosphate deposition, solubilized pore after the salt acid treatment with calcium ion earlier.
5. 5. a kind of calcium ion as claimed in claim 1 crosslinked on fiber the method for grafting mesoporous silica gel; It is characterized in that described calcium silicates is to realize through the carboxylate radical on the calcium ion cross filament and silicate, so calcium silicates and fiber can be accomplished reasonable combination.
6. 6. a kind of calcium ion as claimed in claim 1 crosslinked on fiber the method for grafting mesoporous silica gel; It is characterized in that after persalt is handled; Obtain having the silica gel surface of abundant Si-OH functional group on the surface of calcium silicates; Described mesoporous silica gel layer is the pH value through control solution, can obtain the meso-hole structure in the different apertures of 2-10nm.