CN1105678C

CN1105678C - Preparation of low temperature sinterable hydroxyapatite powder

Info

Publication number: CN1105678C
Application number: CN 00127421
Authority: CN
Inventors: 高濂; 李蔚
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2000-11-10
Filing date: 2000-11-10
Publication date: 2003-04-16
Anticipated expiration: 2020-11-10
Also published as: CN1308016A

Abstract

The present invention relates to a preparation method for low-temperature sintered nanometer hydroxyapatite powder, which belongs to the field of fine chemistry industry. Market calcium nitrate and ammonium dihydrogen phosphate with a low price are used as raw materials for preparing the nanometer hydroxyapatite powder through processes of precipitating, ageing, washing, drying, etc. The method of the present invention is mainly characterized in that a dispersing agent is added before the ageing process, or ultrasonic dispersion is carried out after the ageing process for reducing the agglomeration, so the relative density of the obtained nanometer hydroxyapatite powder reaches 98%, after being sintered through heat preserving for 2 hours at 950 DEG C, and the average crystal grain size is smaller than 140 nm.

Description

A kind of preparing nano hydroxyapatite powder of able to sinter at low temp

Technical field

The present invention relates to a kind of preparing nano hydroxyapatite powder, belong to field of fine chemical.

Background technology

Hydroxyapatite (HAp) is the material that a kind of utmost point has application prospect.It is that skeleton is organized main inorganic components, contains necessary calcium of tissue and phosphoric, does not contain other harmful element again.After implanting, under the effect of body fluid, calcium and the phosphorus material surface that can dissociate is absorbed by body tissue, and the tissue that makes new advances of growth.Hydroxyapatite can form chemical bond with the skeleton tissue and combine, and is a kind of typical biological active materials.Studies show that: the crystal grain of hydroxyapatite material is thin more, and its biological activity is high more.In addition, hydroxyapatite still is a kind of good humidity-sensitive material, and the humidity-sensitive element for preparing with hydroxyapatite has good ageing resistance.On present world market, the price of hydroxylapatite powder surpasses 1000 dollars of per kilograms.

Because hydroxyapatite is not a kind of natural mineral, therefore mainly obtain by synthetic.The method for preparing at present hydroxylapatite powder is a lot, and common have the precipitator method, hydrolysis method, hydrothermal method and a solid phase method etc.The hydrothermal method required equipment is complicated, expensive, and the solid phase method energy consumption is big, and the precipitator method are simple with technology, equipment is cheap, output is big and be used widely.But the precipitator method also have some shortcomings, easily produce reunion, quality as powder and not really stablize or the like.

Summary of the invention

The present invention is the improvement to the common precipitator method.But purpose provides a kind of method of low-temperature sintering with the nano hydroxyapatite powder of acquisition close grain hydroxyapatite material that can be mass-produced, reunite less.This method technology is simple, constant product quality, cost are lower.

Preparation method provided by the invention is to be raw material with inorganic calcium salt and phosphoric acid salt, by under certain pH value precipitin reaction taking place, adds an amount of dispersion agent after ageing, washing, oven dry obtain little, the few HAp powder of reuniting of crystal grain.Its process flow sheet as shown in Figure 6.

Now details are as follows with each relevant process:

1. the selection of inorganic salt raw material: select commercially available nitrocalcite Ca (NO cheap and easy to get for use ₃) ₃With primary ammonium phosphate NH ₄H ₂PO ₄Reaction equation is:

2. the selection of inorganic salt concentration: two kinds of raw materials all are controlled between the 1-2 mol, and concentration is crossed to hang down and then yielded poorly.In the churned mechanically while, the aqueous solution of primary ammonium phosphate is added drop-wise to reaction precipitation in the solution of nitrocalcite.

3. precipitation process pH value: be controlled between the 9-11, mix to stir.

4. the selection of dispersion agent: can select polyacrylic acid, polyoxyethylene glycol (molecular weight is 2000) etc., it is 0.5-4% with respect to throw out that institute adds the dispersion agent amount, preferential 2-3% (mass percent).

5. ageing temperature and time: temperature should be controlled between 60-80 ℃, and the time was controlled between 12-24 hour.Add dispersion agent before the ageing or after ageing ultra-sonic dispersion reunite to reduce, this is the technological process of most critical of the present invention.

6. sedimentary washing: adopt the distilled water wash throw out, to remove foreign ion.

7. take off planar water: for saving time and cost, the present invention adopts common baking oven that throw out is carried out drying and dehydrating.Drying temperature is 120 ℃, and the time is 12 hours.

From the above mentioned, visible outstanding feature of the present invention is:

1. preparation technology is simple, and processing parameter is easy to control, is easy to large-scale industrial production.

2. the present invention adopts and to add after dispersion agent or the ageing method of ultra-sonic dispersion reduce and reunite before ageing, has removed the process of the pure eluting water of usefulness in the general powder preparing process from, provides cost savings.

3. but gained powder of the present invention needn't be through calcining straight forming sintering just, and sintering character is splendid.The relative density of gained HAp can reach about 98% under the condition of 950 ℃/2h, and average crystal grain is less than 140nm.

Description of drawings

Fig. 1 is the electromicroscopic photograph for preparing the powder of HAp with method provided by the invention.Can clearly be seen that with the powder reuniting of method preparation provided by the invention less from photo.

Fig. 2 composes with the XRD of hydroxyapatite block materials behind 1100 ℃/2h sintering of method gained powder preparing provided by the invention.As seen from Figure 2, through (obstructed aqueous vapor protection) behind 1100 ℃, 2 hours sintering, the phase composite of material still is a hydroxyapatite, and any decomposition does not take place, and the stable fine of gained powder is described.

Fig. 3 adds dispersion agent, washes gained hydroxy apatite powder (A) is washed the hydroxy apatite powder (B) of gained through alcohol with not adding dispersion agent the comparison of sintering character without alcohol.X-coordinate is represented sintering temperature among the figure, and ordinate zou is represented the relative density of gained sample.

Fig. 4 is the hydroxy apatite powder (A) for preparing of the present invention and the comparison of the sintering character of commercial hydroxy apatite powder.X-coordinate and the same Fig. 3 of ordinate zou implication.

Fig. 5 directly adds dispersion agent without ageing to wash the gained powder through the XRD spectra of 1100 ℃ of calcinings after 2 hours.

Embodiment

Further specify outstanding feature of the present invention below by example, only be the present invention is described and never limit the present invention, that is outstanding feature of the present invention and marked improvement never are limited to following example.

Example 1:

With concentration is that the pH value of the ammonium dihydrogen phosphate of the nitrocalcite of 1.5 mol and 1.5 mol is adjusted to greater than 9, simultaneously primary ammonium phosphate is added drop-wise in the ca nitrate soln churned mechanically.The throw out of reaction generation is divided into two parts of reactions, a dispersion agent polyoxyethylene glycol (molecular weight is 2000) that adds, add-on is 2% (mass percent), directly dries down at 120 ℃ after ageing, washing again; Another part does not add dispersion agent, dries down at 120 ℃ after ageing, washing back are cleaned 3 times with dehydrated alcohol again.With the dry-pressing of gained powder after the 450MPa isostatic pressing obtains biscuit.The gained biscuit is carried out pressureless sintering (obstructed aqueous vapor protection) under preset temperature, soaking time is 2 hours.Sintered density is as shown in Figure 3: hydroxy apatite powder (A) sintered density under the same conditions of add dispersion agent, washing without alcohol is higher than the powder of washing through alcohol (B).Fig. 4 is the hydroxy apatite powder (A) and commercial hydroxy apatite powder (C that the present invention prepares, Sichuan University produces) moulding under the same conditions after the agglomerating sintering curre, the sintering character with the powder of the inventive method gained obviously is better than commercial hydroxy apatite powder as can be seen.

Example 2:

Nitrocalcite and primary ammonium phosphate reaction postprecipitation thing are divided into 11 parts.Five parts add dispersion agent polyoxyethylene glycol (molecular weight is 2000), and add-on is 0.5,1,2,3,4% (mass percent is with respect to throw out, down together), and five parts add polyacrylic acid, and add-on also is 0.5,1,2,3,4%, and another part does not add dispersion agent.With all throw out ageings after 12 hours, the washing oven dry then after dehydration in 120 ℃/1 hour, is measured the specific surface area of powder with the BET method, and the result shows, the specific surface area of adding behind the dispersion agent is improved when not adding dispersion agent, and is as shown in table 1.

The relation of table 1 polyoxyethylene glycol, polyacrylic addition and powder specific surface area

Polyoxyethylene glycol (%)	0.5	1	2	3	4
Polyoxyethylene glycol (%)	0.5	1	2	3	4	Powder specific surface area (m ²/g)	85	101	103	104	107	105
Polyacrylic acid (%)	0.5	1	2	3	4	Powder specific surface area (m ²/g)	85	101	103	104	107	105
Polyacrylic acid (%)	0.5	1	2	3	4	Powder specific surface area (m ²/g)	85	100	102	105	104	103

Example 3:

Nitrocalcite and primary ammonium phosphate are divided into 3 parts, a polyoxyethylene glycol that before reaction, adds, a polyoxyethylene glycol that adds before ageing also has portion to add polyoxyethylene glycol after ageing, and add-on is 3%.After all throw outs were washed oven dry, after dehydration in 120 ℃/1 hour, with the specific surface area of BET method measurement powder, the result showed that the specific surface area before ageing behind the interpolation dispersion agent is the highest, as shown in table 2 then.

Table 2 different time adds the influence of dispersion agent contrast table area

Joining day	Before the reaction	Before the ageing	After the ageing
Joining day	Before the reaction	Before the ageing	After the ageing	Powder specific surface area (m ²/g)	100	107	95

Example 4: nitrocalcite and the reacted throw out of primary ammonium phosphate are divided into two parts, and portion is directly washed after 12 hours 70 ℃ of following ageings; Another part supersound process after ageing was washed in 1 hour again.After the oven dry, through dehydration in 120 ℃/1 hour, measure the specific surface area of powder with the BET method, the result shows, and is than without being significantly improved of ultra-sonic dispersion, as shown in table 3 through the powder specific surface area of supersound process.

Table 3 ultra-sonic dispersion is to the influence of powder specific surface area

Treatment process	Directly washing	Ultra-sonic dispersion
Treatment process	Directly washing	Ultra-sonic dispersion	Powder specific surface area (m ²/g)	85	103

Example 5:

Nitrocalcite and the reacted throw out of primary ammonium phosphate are divided into two parts, and portion is washed after 12 hours 70 ℃ of following ageings; Another part directly adds dispersion agent without ageing and washes.The powder that two kinds of precipitation oven dry, grindings of washing the back gained obtain was calcined 2 hours at 1100 ℃.Fig. 5 is two kinds of XRD spectra behind the powder calcination.From the spectrogram as seen: any decomposition does not take place in the hydroxy apatite powder through the ageing gained under the condition of 1100 ℃/2h, then serious thermolysis can take place without the powder of ageing gained.

Claims

1. the preparing nano hydroxyapatite powder of an able to sinter at low temp is made up of precipitation, ageing, washing, dehydration, drying process, it is characterized in that:

(1) selecting cheap commercially available nitrocalcite and primary ammonium phosphate for use is raw material, and its concentration is controlled in the 1-2 mol scope;

(2) simultaneously primary ammonium phosphate is added drop-wise to reaction precipitation in the ca nitrate soln churned mechanically, by adding NH ₄OH, control pH value of solution value is between 9-11;

(3) ageing temperature should be controlled at 60-80 ℃, and digestion time 12-24 hour is that polyacrylic acid or molecular weight are 2000 polyoxyethylene glycol by adding dispersion agent before the ageing, or ultra-sonic dispersion reduces reunion after the ageing; The add-on of dispersion agent is 0.5-4% (quality) with respect to throw out;

(4) use the distilled water wash throw out;

(5) dehydration, drying, drying temperature is 120 ℃, the time is 12 hours.

2. by the described preparation method of claim 1, it is characterized in that the add-on of dispersion agent is 2-3% (quality) before the described ageing.

3. press the described preparation method of claim 1, but it is characterized in that the gained hydroxy apatite powder needn't be through calcining with regard to the straight forming sintering, sintering temperature is 950-1100 ℃, be incubated 2 hours, when sintering temperature was 950 ℃, relative density can reach 98%, and average crystal grain is less than 140nm.