公开(公告)号：EP0707518B1

公开(公告)日：2000-06-21

申请号：EP94917934.5

申请日：1994-04-28

申请人： The University of New Mexico

发明人： DESHPANDE, Ravindra ,  SMITH, Douglas, M. ,  BRINKER, C. Jeffrey

IPC分类号： B01J13/00 ,  B05D7/00 ,  C03C17/30 ,  E04B1/74

CPC分类号： B01J13/0091 ,  C01B33/163 ,  Y02P20/544 ,  Y10T428/2995

公开(公告)号：EP0707518A1

公开(公告)日：1996-04-24

申请号：EP94917934.0

申请日：1994-04-28

申请人： The University of New Mexico

发明人： DESHPANDE, Ravindra ,  SMITH, Douglas, M. ,  BRINKER, C., Jeffrey

IPC分类号： B01J13 ,  C01B33

CPC分类号： B01J13/0091 ,  C01B33/163 ,  Y02P20/544 ,  Y10T428/2995

摘要： This invention provides an extremely porous xerogel dried at vacuum to below-supercritical pressures but having the properties of aerogels which are typically dried at supercritical pressures. This is done by reacting the internal pore surface of the wet gel (e.g. alkoxide-derived silica gel) with an organic surface modification agent (e.g. trimethylchloro-silane in benzene) in order to change the contact angle of the fluid meniscus in the pores during drying. Shrinkage of the gel (which is normally prevented by the use of high autoclave pressures, such that the pore fluid is at temperature and pressure above its critical value) is avoided even at vacuum or ambient pressures. The figure 4 shows a change in sample weight and sample length during drying for surface modified, ambient pressure gel processed in accordance with the invention, illustrating the initial shrinkage followed by expansion of the gel during the final stages of drying. The extremely low density finely pored gel products have useful insulating and other properties.