SOL-GEL TRANSITION IN SIMPLE SILICATES
SOL-GEL TRANSITION IN SIMPLE SILICATES
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DOI：
10.1016/0022-3093(82)90245-9
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发表时间：
1982-01-01
影响因子：
3.5
通讯作者：
ASHLEY, CS
中科院分区：
文献类型：
--
作者：
BRINKER, CJ;KEEFER, KD;ASHLEY, CS
硅酸盐凝胶是在一系列条件下制备的，在这些条件下，水解率相对于缩合速度从快到慢变化。当水解速度较快时，在凝胶化过程中会形成更大、更高凝聚度的聚合物。相反，对于缓慢的水解，会形成较小的、较不高度浓缩的聚合物。这些凝胶分别干燥成低密度粗质构和高密度细质构凝胶。需要高温(>；800°C)才能通过粘性烧结使粗凝胶致密。较低的温度足以使精细凝胶致密，这一过程被认为是由聚合物松弛、随后的冷凝和孔洞坍塌组成的。
Silicate gels were prepared under a range of conditions in which the rate of hydrolysis was varied from fast to slow with respect to the rate of condensation. When hydrolysis was fast, larger, more highly condensed polymers were formed during gelation. Conversely, for slow hydrolysis, smaller, less highly condensed polymers were formed. These gels dried to low density coarse textured and high density fine textured gels, respectively. High temperatures, (>800°C) were required to densify the coarse gels by viscous sintering. Lower temperatures were sufficient to densify fine gels by a process which was postulated to consist of polymer relaxation followed by condensation and pore collapse.