摘要:
Synthesis and use of a new class of polymeric materials with favorable separation characteristics for the dehydration of ethanol and other organic solvents is described herein. The thermally rearranged (TR) polybenzoxazole (PBO), polybenzimidazole (PBI) and polybenzothiazole (PBT) membranes of the present invention can be used for the dehydration of ethanol during processing to fuel grade biodiesel by either pervaporation or vapor permeation. The unique microstructure of the membranes provides excellent separation characteristics, and this, coupled with their inherent thermal and chemical stability, enables their usage in other separations, such as the dehydration of other organic solvents.
摘要:
The present invention includes a polymer formed by the thermal rearrangement of an ortho-functional polyimide synthesized via chemical imidization with permeation properties for gas separation membranes higher than those synthesized via thermal imidization and a method for forming that polymer having tailored transport properties and different chemical resistance. The present invention also includes a polymer formed by the thermal rearrangement of an ortho-functional polyimide in which a portion of the ortho-position functional group is lost during thermal rearrangement to yield a thermally rearranged polymer with higher permeability than would be seen without the ortho-position group. This ortho-position group can be the result of chemical imidization, or the result of a post-imidization modification reaction.