Modified freeze dehydration method for preparing porous material

A technology of freeze-drying and porous materials, which is applied in the direction of drying solid materials without heating, drying solid materials, drying, etc., which can solve the problems of less porous ceramics and metal materials, and achieve the effect of increasing strength

Inactive Publication Date: 2007-10-10
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] At present, there are few reports on the preparation of poro

Method used

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  • Modified freeze dehydration method for preparing porous material
  • Modified freeze dehydration method for preparing porous material
  • Modified freeze dehydration method for preparing porous material

Examples

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example 1

[0043] Example 1: In a 250mL polyethylene mill bottle, weigh 20g of hydroxyapatite, add 0.22g of potassium polyacrylate and 19.6g of deionized water, and add a certain proportion of alumina balls, ball mill and mix for 24 hours. Put the dispersed slurry into a vacuum drying oven for vacuum degassing. Then pour the slurry with the air bubbles removed into the mold, put it into the freezer of the refrigerator and freeze it at a low temperature of -10 to -20°C for about 48 hours. After the solid is formed, take the hydroxyapatite solid out of the mold and immediately put it into the drying oven of a freeze dryer, first keep it at 10°C and a vacuum of 9Pa for 4h, then raise the temperature of the sample to 60°C, and keep it warm for about 5h. Finally, a porous hydroxyapatite green body is obtained. The freeze-dried porous green body was sintered at 1300°C for 1 hour to obtain porous hydroxyapatite, whose bulk density and open porosity were 2.12g / cm 3 and 28.5%.

example 2

[0044] Example 2: In a 250mL polyethylene mill bottle, weigh 20g of hydroxyapatite, add 0.22g of potassium polyacrylate and 19.6g of deionized water, and add a certain proportion of alumina balls, ball mill and mix for 24 hours. Add 3.33g of PVA aqueous solution with a concentration of 12wt%, mechanically stir for 0.5h, and put the dispersed slurry into a vacuum drying oven for vacuum degassing. Then pour the slurry with the air bubbles removed into the mold, put it into the freezer of the refrigerator and freeze it at a low temperature of -10 to -20°C for about 48 hours. After the solid is formed, take the hydroxyapatite solid out of the mold and immediately put it into the drying oven of a freeze dryer, first keep it at 10°C and a vacuum of 9Pa for 4h, then raise the temperature of the sample to 60°C, and keep it warm for about 5h. Finally, a porous hydroxyapatite green body is obtained. The freeze-dried porous green body was sintered at 1300°C for 1 hour to obtain porous h...

example 3

[0045] Example 3: In a 250mL polyethylene mill bottle, weigh 20g of hydroxyapatite, add 0.22g of potassium polyacrylate and 19.6g of deionized water, and add a certain proportion of alumina balls, ball mill and mix for 24 hours. Add 10 g of PVA aqueous solution with a concentration of 12 wt %, mechanically stir for 0.5 h, and put the dispersed slurry into a vacuum drying oven for vacuum degassing. Then pour the slurry with the air bubbles removed into the mold, put it into the freezer of the refrigerator and freeze it at a low temperature of -10 to -20°C for about 48 hours. After the solid is formed, take the hydroxyapatite solid out of the mold and immediately put it into the drying oven of a freeze dryer, first keep it at 10°C and a vacuum of 9Pa for 4h, then raise the temperature of the sample to 60°C, and keep it warm for about 5h. Finally, a porous hydroxyapatite green body is obtained. The freeze-dried porous green body was sintered at 1300°C for 1 hour to obtain porous...

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Abstract

This invention relates to an improved method for preparing porous material by freeze-drying. The method comprises: selecting organic additive, mixing the additive with the matrix powder, molding, and sintering. The method can prepare porous green body by controlling the solid content of the slurry, as well as the cooling rate, and then prepare porous material by sintering. The obtained porous material has a porosity of 10-90%, and an average particle size of 0.2-300 mu.m.

Description

technical field [0001] The invention relates to an improvement of porous materials prepared by a freeze-drying method, more precisely, relates to the control of the microstructure of porous materials by organic additives in the freeze-drying method, and belongs to the field of preparing porous materials by freeze-drying methods. Background technique [0002] At present, the methods for preparing porous materials mainly include organic foam impregnation method, adding pore-forming agent method, sol-gel method and freeze-drying method. The ideal technology not only requires the ability to prepare materials with complex structures, controllable shape and size of pores, and certain mechanical properties, but also requires low cost and simple process. Compared with other preparation methods, the freeze-drying method can obtain porous materials with small shrinkage, large porosity range, good mechanical properties and complex shapes. It is a simple, practical, short preparation cy...

Claims

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Application Information

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IPC IPC(8): C04B38/00F26B5/06
Inventor 左开慧曾宇平江东亮
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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