CN111690155A

CN111690155A - Preparation method of nano-cellulose/hydroxyapatite nanospheres

Info

Publication number: CN111690155A
Application number: CN202010073032.XA
Authority: CN
Inventors: 安兴业; 胡钦; 刘佳雯; 刘洪斌; 刘利琴; 张伟
Original assignee: Tianjin University of Science and Technology
Current assignee: Tianjin University of Science and Technology
Priority date: 2020-01-11
Filing date: 2020-01-11
Publication date: 2020-09-22
Anticipated expiration: 2040-01-11
Also published as: CN111690155B

Abstract

The invention belongs to a preparation method for synthesizing nano-cellulose/hydroxyapatite nanospheres by taking nano-cellulose as a template agent, which comprises the following components: 0.05-0.5 wt% of nano-cellulose, 0.1-0.5 wt% of calcium chloride, 0.1-0.5 wt% of ammonium dihydrogen phosphate and 0.1-2.0 wt% of sodium hydroxide, and the preparation method comprises the following steps: 1) diluting the prepared nano-cellulose suspension into 0.05-0.5 wt% methanol suspension, performing ultrasonic treatment for 10-30min, and adding 30-150g of 0.05-0.5 wt% dispersed nano-cellulose suspension into a beaker under the condition of magnetic stirring; 2) adjusting pH of the suspension to 9-11.2 with 2-10mL of sodium hydroxide aqueous solution under magnetic stirring at 25-40 deg.C, stirring for 10-30min, adding 2-10mL of ammonium dihydrogen phosphate aqueous solution, and stirring for 30-60 min; finally, adding 2-10mL of calcium chloride aqueous solution and stirring for 2-5 h; 3) and (3) centrifugally separating and washing the suspension for 2-4 times under the centrifugal action of 10000r/min by adopting an ethanol solution and deionized water, and obtaining the nano-cellulose/hydroxyapatite composite aerogel through a freeze-drying technology.

Description

Preparation method of nano-cellulose/hydroxyapatite nanospheres

Technical Field

The invention relates to a preparation method for synthesizing nanocellulose/hydroxyapatite nanospheres by taking nanocellulose as a template agent, which is mainly applied to the fields of biomedicine, adsorption catalysis and papermaking.

Background

With the development of nanotechnology, it is gradually recognized that nanoparticles have unique properties such as unique surface effect, small size effect and quantum effect. The unique properties of the nano material reach different levels of knowledge with the development of nano technology, the previous research focuses on controlling the stoichiometric ratio of the product, and the research focuses mainly on controlling the size and the shape of the crystal.

Hydroxyapatite is an important biomaterial due to its unique bioactivity and biocompatibility. In order to expand the research value and application range of hydroxyapatite, hydroxyapatite nanoparticles with various shapes and different spatial structures are prepared, and become a hotspot of research in the field of biological materials. In different preparation methods of hydroxyapatite, hydroxyapatite crystal grains/particles with different shapes, particle sizes and crystallinity degrees can be obtained by controlling different parameters such as reaction additives, template agents, reaction temperature, pH values and the like, wherein the hydroxyapatite crystal grains/particles comprise hydroxyapatite nanospheres. Currently, most of the research focuses on regulating and controlling the morphology and structure of hydroxyapatite by using an external additive. The principle is that the template and the solution are utilized to influence the phase interface of an inorganic substance, and under the action of the template, the inorganic material with special morphology and structure can be obtained through crystal nucleation and growth. The template has an important position in the biomimetic synthesis technology, and the synthesis method for regulating and controlling various templates is an important means for preparing inorganic materials with different structures and performances.

The natural cellulose is used as a renewable resource on the earth, and has the characteristics of wide source, biodegradability, renewability and low cost. However, cellulose is a naturally occurring compound, and has the disadvantages of incomplete structure, poor physical form, easy corrosion, easy fracture and the like, so that the cellulose is hindered to a certain extent in practical application. The cellulose is prepared into the nano-scale high polymer material, and the performance of the nano-scale high polymer material can be optimized to a certain extent by utilizing the nano-size effect, so that the application field of the renewable resource is enlarged. Different types of nanocellulose can be obtained by different treatment methods (including chemical treatment, mechanical treatment, enzymatic hydrolysis, bacterial synthesis, electrostatic spinning, artificial synthesis, etc.). According to different preparation methods and different raw materials, the method can be divided into the following steps: nanocellulose can be classified into microfibrillated cellulose (MFC), fibrillated Cellulose (CNF), Cellulose Nanocrystals (CNC), bacterial nanocellulose (BC), algal nanocellulose (AC). It not only has the characteristics of cellulose, but also has a plurality of excellent characteristics of high Young modulus, high crystallinity, high water absorption, high polymerization degree and the like. Each nanocellulose differs in shape, size, aspect ratio, crystal structure and properties.

The characteristics of the nano-cellulose and the hydroxyapatite are combined, the nano-cellulose is taken as a template agent, the natural, non-toxic, easily degradable and environment-friendly nano-cellulose is taken as the template agent, and the nano-cellulose/hydroxyapatite nanosphere composite material which has good biocompatibility, bioactivity, bone conductivity, high temperature resistance, flame retardant property and large specific surface area is developed and has great significance when being applied to the fields of biomedicine, adsorption catalysis, paper making and the like.

The preparation process of the hydroxyapatite nanosphere is simple and easy to implement. Under the regulation and control action of the nano-cellulose and the methanol, the hydroxyapatite nanospheres gradually grow and nucleate by taking the nano-cellulose as a nucleation site, and finally the nanospheres with uniform size are formed. The nano-cellulose, the hydrated calcium chloride, the dihydric phosphate and the sodium hydroxide have the advantages of wide raw material source, low price, no toxicity, no carcinogenesis, environmental protection and no pollution in the preparation process, and the preparation process is simple and easy to implement. The invention first utilizes biodegradable nano-cellulose to prepare the hydroxyapatite nanosphere.

Disclosure of Invention

The invention aims to develop a method for preparing nano-cellulose/hydroxyapatite nanospheres by using nano-cellulose as a template agent, overcome the tendency that hydroxyapatite self-aggregates and nucleates and finally grows into nanospheres, blocks and hydroxyapatite with uneven appearance similar to flower shape, and realize that the hydroxyapatite forms the nanospheres with consistent appearance under the induction action of the nano-cellulose and methanol. Has the characteristics of environmental protection, biological activity, no toxicity and no pollution.

The invention is realized by the following steps of the technical scheme:

step 1: diluting the prepared nano-cellulose suspension to 0.05-0.5 wt% of methanol suspension, carrying out ultrasonic treatment for 10-30min, and adding 30-150g of 0.05-0.5 wt% of the dispersed nano-cellulose suspension into a beaker under the condition of magnetic stirring;

step 2: adjusting pH of the solution to 9-11.2 with 2-10mL of sodium hydroxide aqueous solution under magnetic stirring at 25-40 deg.C, stirring for 10-30min, adding 2-10mL of ammonium dihydrogen phosphate aqueous solution, and stirring for 30-60 min; finally, adding 2-10mL of calcium chloride aqueous solution and stirring for 2-5 h;

and step 3: and (3) centrifugally separating and washing the suspension for 2-4 times under the centrifugal action of 8000-12000r/min by adopting an ethanol solution and deionized water, and obtaining the nano-cellulose/hydroxyapatite nanosphere composite material by a freeze-drying technology.

The nano-cellulose raw material in the step 1 is derived from any one of needle wood, broad leaf wood, non-wood fiber raw material and bacterial fiber.

The concentration of the calcium chloride solution is 0.1-0.5 wt%.

The concentration of the ammonium dihydrogen phosphate solution is 0.1-0.5 wt%.

The concentration of the sodium hydroxide solution is 0.1-2.0 wt%.

And 2, adding the ammonium dihydrogen phosphate and the sodium hydroxide solution in the step 2 in a mode of 3-8 seconds per drop.

The invention has the beneficial effects that:

the preparation process of the hydroxyapatite nanosphere is simple and easy to implement. Under the regulation and control action of the nano-cellulose and the methanol, the hydroxyapatite nano precursor particles can form uniform hydroxyapatite nanospheres on the surface of the nano-cellulose, and the diameters of the nanospheres are within the range of 60-500 nm.

The nano-cellulose, the calcium chloride, the phosphate and the sodium hydroxide have the advantages of wide raw material sources, low price, no toxicity, no carcinogenesis, environmental protection and no pollution in the preparation process, and the preparation process is simple and easy to implement. The invention prepares the hydroxyapatite nanosphere by using biodegradable nano-cellulose in a methanol solvent for the first time.

Drawings

Fig. 1 (a) is an SEM image of pure nanocellulose; (c) SEM picture of pure hydroxyapatite with methanol as solvent; (b) SEM picture of pure hydroxyapatite with deionized water as solvent; (d) is SEM picture of nano cellulose/hydroxyapatite nano sphere composite material;

Detailed Description

The invention will be further illustrated by the following examples

Example 1

Diluting the prepared nano cellulose gel into 0.06 wt% deionized water suspension at 26 ℃, performing ultrasonic treatment for 10min to form uniform 50g of suspension, adding 50g of the 0.06 wt% dispersed nano cellulose suspension into a 150mL beaker under the condition of magnetic stirring, continuously stirring for 4h under the action of a magnetic stirrer, and then performing freeze drying technology at-55 ℃ for 16h to form the nano cellulose aerogel. Scanning Electron Microscopy (SEM) testing was performed.

Example 2

Adding 0.1 wt% of sodium hydroxide aqueous solution prepared in advance into 50g of methanol solution at 26 ℃ under the action of magnetic stirring, adjusting the pH value to 11.0, stirring for 20min, then adding 3mL of 0.1 wt% ammonium dihydrogen phosphate aqueous solution, and stirring for 30 min; finally, 3mL of 0.1 wt% aqueous calcium chloride solution was added and stirred for 4h, followed by aging for 12 h. Freeze-drying at-60 deg.C for 16 hr to obtain pure hydroxyapatite powder. Finally, the powder obtained is subjected to Scanning Electron Microscopy (SEM) testing.

Example 3

Diluting the prepared nano cellulose gel into 0.06 wt% methanol suspension at 26 ℃, carrying out ultrasonic treatment for 10min to form uniform 50g methanol suspension, adding 0.1 wt% sodium hydroxide aqueous solution prepared in advance into the suspension under the condition of magnetic stirring, adjusting the pH value to 11.0, stirring for 20min, then adding 3mL of 0.1 wt% ammonium dihydrogen phosphate aqueous solution, and stirring for 30 min; finally, 3mL of 0.1 wt% aqueous calcium chloride solution was added and stirred for 4h, followed by aging for 12 h. And freeze-drying the mixture for 16 hours at the temperature of minus 60 ℃ to form the nano-cellulose/hydroxyapatite composite material. And finally, carrying out Scanning Electron Microscope (SEM) test on the obtained composite material.

The test result shows that the pure hydroxyapatite has different shapes, nanospheres and blocks and uneven sizes. After the nano-cellulose is introduced as a template agent and methanol is introduced as a template agent, the growth and crystallization of the self-nucleation of the hydroxyapatite into blocks can be effectively prevented. Because the surface of the nano-cellulose has hydroxyl and carboxyl, under the electrostatic action, calcium ions can be effectively adsorbed on the surface of the cellulose and methanol increases the steric hindrance of the solvent, and finally the nano-cellulose/hydroxyapatite nanosphere composite material with consistent appearance is formed.

The hydroxyapatite particles are easy to aggregate into blocks in methanol, the size is large, the uniformity is poor, the nanocellulose is introduced to serve as a carrier, the aggregation and self-growth nucleation of the apatite particles can be effectively avoided, the methanol can serve as a solvent to further prevent the self-aggregation of the hydroxyapatite due to the fact that the steric hindrance is large, the size and the distribution of the hydroxyapatite can be regulated and controlled again, and the apatite nanosphere particles which are smaller in size and more uniform in particle size distribution are obtained. As can be seen from the SEM in fig. 1(d), under the cooperative control of the cellulose nanofibrils and methanol, the hydroxyapatite nanosphere particles are small and uniformly distributed. Therefore, under the common regulation and control action of the nano-cellulose and the methanol, the preparation of the hydroxyapatite nanosphere/CNF composite material with adjustable size and distribution can be realized.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A preparation method of nano-cellulose/hydroxyapatite nanospheres is characterized by comprising the following steps:

step 1: diluting the prepared nano-cellulose suspension into 0.05-0.5 wt% of methanol suspension, carrying out ultrasonic treatment for 10-30min, and adding 30-150g of 0.05-0.5 wt% of the dispersed nano-cellulose suspension into a beaker under the condition of magnetic stirring;

and step 3: and (3) centrifugally separating and washing the suspension for 2-4 times under the centrifugal action of 8000-12000r/min by adopting an ethanol solution and deionized water, and obtaining the nano-cellulose/hydroxyapatite composite aerogel through a freeze-drying technology.

2. The method of claim 1, further comprising: the nano-cellulose is oxidized by a TEMPO system of the raw material, so that the surface of the nano-cellulose is negatively charged. The raw material is selected from any one of needle wood, broad leaf wood, bamboo, cotton pulp and hemp fiber.

3. The method of claim 1, further comprising: the concentration of the cellulose nanofibril suspension is 0.05-0.5 wt%.

4. The method of claim 1, further comprising: the concentration of the calcium chloride solution is 0.1-0.5 wt%.

5. The method of claim 1, further comprising: the concentration of the ammonium dihydrogen phosphate solution is 0.1-0.5 wt%.

6. The method of claim 1, further comprising: the concentration of the sodium hydroxide solution is 0.1-2.0 wt%.

7. The method of claim 1, further comprising: and 2, adding the sodium hydroxide in a drop manner of 3-8 seconds.

8. The method of claim 1, further comprising: the mass fraction of methanol in the methanol solvent is 60-80%.