Monolithic column
Permeable polymeric monolithic materials are prepared in a plastic column casing. In one embodiment, the permeable polymeric monolithic materials are polymerized by the application of heat from an external source starting at a low temperature such as 40 degrees centigrade, depending on the mixture and size of the column, and continuing at a higher temperature, such as 60 degrees centigrade. The temperature at the start of the polymerization is low enough so as not to cause exothermal run-away conditions and to avoid high heat of reaction that would prevent a substantially constant temperature across the cross-section of the column. The higher temperature is used after sufficient monomer depletion has occurred and steric interference has increased so the polymerization reaction is sufficiently slow to avoid heat of reaction generation high enough to cause significant reduction in the homogeneousness of the pore sizes.
1. A method of making a monolithic chromatography column, said method comprising the steps of
(a) adding a polymerization mixture containing a porogen to a chamber,
(b) polymerizing the polymerization mixture in the chamber to form a monolithic chromatography polymer plug in the shape of a chromatography column, at least part of said polymerizing being performed by applying sufficient pressure to the polymerization mixture to prevent wall channel openings in said polymerized monolithic polymer plug and while heating the polymerization mixture at a controlled elevated temperature, and said polymerization is performed under temperature-time moderating conditions, whereby temperature gradients are controlled to prevent substantial cross sectional variations in the monolithic polymer plug, and
(c) washing the polymer plug to remove the porogen.
2. The method of claim 1 in which the monolithic polymer plug is formed in a chromatography column.
3. The method of claim 1 in which the monolithic polymer plug is formed in a capillary tube column.
4. The method of claim 1 in which polymerizing is performed under a pressure of at least 80 psi during at least part of said polymerizing.
5. The method of claim 1 in which polymerizing is performed under a pressure of at least 150 psi during at least part of said polymerizing.
6. The method of claim 1 in which polymerizing is performed under a pressure of at least 180 psi during at least part of said polymerizing.
7. The method of claim 1 in which the pressure is applied in intervals of increasing pressures.
8. The method of claim 1 in which said pressure is sufficient to prevent voids from being formed inside the polymer plug.
9. The method of claim 1 in which said controlled elevated temperature is increased gradually during polymerization by controlling the temperature on the outside of the chamber.