Siloxane Elastomer Foams
Siloxane Elastomer Foams
复制标题
硅氧烷弹性体泡沫
DOI：
10.1021/bk-1997-0669.ch002
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发表时间：
1997
影响因子：
19
通讯作者：
R. D. Miller
中科院分区：
文献类型：
--
作者：
A. Martina;J. Hilborn;J. Kiefer;J. Hedrick;S. Srinivasan;R. D. Miller
已经开发了生产具有微米范围内的孔隙率的可注射成型的弹性体泡沫的新方法。在第一种方法中，通过首先在适当的表面活性剂的存在下制备反相乳液来将水分散在硅氧烷网络内。然后通过抽空水来产生孔隙。超临界干燥用于避免表面张力效应并防止干燥过程中的塌陷。所测量的孔隙率与掺入初始乳液中的水具有良好的一致性。调查的第二种方法，作为一种手段，在弹性体中产生控制的孔隙率涉及到混合热不稳定的颗粒到硅氧烷树脂。在网络形成时，颗粒可以选择性地降解以留下空隙，空隙的尺寸和形状应该与初始分散体形态的尺寸和形状相同。采用分散聚合和链转移相结合的方法合成了具有较低热稳定性的聚甲基丙烯酸甲酯颗粒。所得颗粒显示出降解温度的显著降低。这两种技术的弹性体泡沫的制备进行了说明。
New approaches to produce injection moldable elastomeric foams with porosities in the micrometer range have been developed. In the first approach, water is dispersed within the siloxane network by first preparing a reverse emulsion in the presence of an appropriate surfactant. Porosity is then generated by evacuation of the water. Supercritical drying was used to avoid surface tension effects and prevent collapse during drying. The measured porosities were in good agreement with the water incorporated into the initial emulsion. The second approach surveyed as a means of generating controlled porosity in elastomers involves blending thermally labile particles into the siloxane resin. Upon network formation, the particles can be selectively degraded to leave voids, the size and shape of which should be identical to that of the initial dispersion morphology. PMMA particles with deliberate low thermal stability were synthesized using a combination of dispersion polymerization and chain transfer. The resulting particles showed a significant decrease in degradation temperature. These two techniques for the preparation of elastomeric foams are described.