不同尺寸钙磷陶瓷球形多孔颗粒的制备及孔隙控制
发布时间：2019-05-18 04:44
【摘要】：钙磷生物陶瓷是一类主要由磷酸盐组成的材料,在组成元素和结构上与人体骨组织和牙的无机成分相近,具有优良的骨传导性和生物活性,广泛应用于硬组织修复和替换。钙磷生物陶瓷材料可以制成块状、粉体和颗粒状,以满足不同应用要求。球形颗粒因具有堆积密度高、流动性好和不容易团聚的优点,近年来受到更多关注。本文采用液滴-冷凝法制备钙磷陶瓷球形多孔颗粒,对制备工艺进行深入研究,通过改变材料组成和制备工艺参数,实现不同尺寸和孔隙结构的球形颗粒的可控制备。为降低钙磷陶瓷的烧结温度,在陶瓷浆料中加入无机盐,在较低烧结温度时形成低共熔相促进烧结。加入以淀粉为主的有机添加剂,提高陶瓷浆料悬浮稳定性,提高制备颗粒成分的均匀性,使制备工艺稳定。二甲基硅油作为冷凝液具有比较合适的密度和粘度,可以使浆料液滴充分凝固；而正庚烷和苯甲醚作为冷凝液时,由于其密度和粘度都较小,需要冷凝液有更高的液柱才能保证成形。浸泡颗粒模拟体液的pH变化在7-7.6的范围内,在模拟体液中的颗粒可以成为碳酸羟基磷灰石(CHA)沉积的基底。而无机添加剂的加入,特别是硫酸盐添加剂的加入可以促进CHA的沉积。影响制备球形颗粒尺寸的因素包括浆料粘度、烧结温度和装置出口的内径,其中起决定性作用的因素是浆料出口的内径。对应不同的出口内径,存在一个合适的浆料粘度,使用具有相对应粘度的有机添加剂,可以稳定地制备球形颗粒,过低或过高的浆料粘度,都会使成形工艺无法进行。碱糊法制备的淀粉有机添加剂粘度变化范围较大,改变其保温的温度可以提高粘度,便于制备2-3mm的球形颗粒；提高浆料中淀粉含量可以在较大范围内增大浆料的粘度,可用于制备3-5mm的球形颗粒。球形颗粒的孔隙主要来源于溶剂结晶升华留下的空间,颗粒中心区域以等轴状孔隙为主,边缘区域则是形状不规则且孔径较小的孔隙。通过控制浆料的冷凝温度,可以得到具有不同孔隙率和孔径的颗粒。-25℃冷凝得到的球形颗粒具有比较高的孔隙率以及合适的平均孔径。烧结会使较高冷凝温度(-15℃和-20℃)制备颗粒孔隙的孔径减小,而使较低冷凝温度(-25℃和-30℃)制备颗粒孔隙的孔径增加。添加炭粉作为造孔剂,一方面在液滴冷凝时会阻碍溶剂的结晶,但不会影响孔隙平均孔径；另一方面,造孔剂烧失之后会在一定程度上改变颗粒的孔隙结构。加入5%造孔剂制备颗粒的孔隙具有最大的平均孔径,而加入10%造孔剂制备颗粒的孔隙具有最高的孔隙率。颗粒孔隙主要还是以较小的孔隙(小于21.43μm)为主,造孔剂的加入只会影响较大孔隙的形貌、数量和孔隙率。
[Abstract]:Calcium phosphorus bioceramic is a kind of material mainly composed of phosphate. It is similar to the inorganic composition of human bone tissue and teeth in composition elements and structure. It has excellent bone conductivity and biological activity and is widely used in hard tissue repair and replacement. Calcium phosphorus bioceramic materials can be made into bulk, powder and particles to meet different application requirements. Spherical particles have attracted more and more attention in recent years because of their high stacking density, good mobility and not easy agglomeration. In this paper, the spherical porous particles of calcium and phosphorus ceramics were prepared by droplet condensation method, and the preparation process was deeply studied. by changing the composition and preparation parameters of the materials, the controllable preparation of spherical particles with different sizes and pore structures was realized. In order to reduce the sintering temperature of calcium-phosphorus ceramics, inorganic salt was added to the ceramic slurry to form low eutectic phase to promote sintering at lower sintering temperature. Adding starch as the main organic additive can improve the suspension stability of ceramic slurry, improve the uniformity of preparation particle composition, and make the preparation process stable. Dimethyl silicone oil as condensate has more suitable density and viscosity, which can fully solidify the slurry droplets. When n-hexane and anisole are used as condensate, because of their low density and viscosity, higher liquid column is needed to ensure the formation of condensate. The pH of simulated body fluid changed in the range of 7 鈮，
本文编号：2479682
[Abstract]:Calcium phosphorus bioceramic is a kind of material mainly composed of phosphate. It is similar to the inorganic composition of human bone tissue and teeth in composition elements and structure. It has excellent bone conductivity and biological activity and is widely used in hard tissue repair and replacement. Calcium phosphorus bioceramic materials can be made into bulk, powder and particles to meet different application requirements. Spherical particles have attracted more and more attention in recent years because of their high stacking density, good mobility and not easy agglomeration. In this paper, the spherical porous particles of calcium and phosphorus ceramics were prepared by droplet condensation method, and the preparation process was deeply studied. by changing the composition and preparation parameters of the materials, the controllable preparation of spherical particles with different sizes and pore structures was realized. In order to reduce the sintering temperature of calcium-phosphorus ceramics, inorganic salt was added to the ceramic slurry to form low eutectic phase to promote sintering at lower sintering temperature. Adding starch as the main organic additive can improve the suspension stability of ceramic slurry, improve the uniformity of preparation particle composition, and make the preparation process stable. Dimethyl silicone oil as condensate has more suitable density and viscosity, which can fully solidify the slurry droplets. When n-hexane and anisole are used as condensate, because of their low density and viscosity, higher liquid column is needed to ensure the formation of condensate. The pH of simulated body fluid changed in the range of 7 鈮，
本文编号：2479682
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