Polybenzazole polymer containing indan moieties may be synthesized. Those polymers can be fabricated into membranes, which are useful for gas separations.
Polybenzazole polymers can be synthesized rapidly in large quantities at high molecular weight and high concentration by a two-step process of forming oligomers in a batch reactor and advancing the molecular weight of the polymer in an extruder.
Separation membranes excellent in strength, durability, heat resistance and solvent resistance as well as in balance between substance separation properties and substance permeability are disclosed, which are formed from polyhydrazidoimide resins, and preferably comprises a non-porous dense layer formed from a polyhydrazidoimide resin obtained from the reaction of an aromatic tetracarboxylic dianhydride such as 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and an aromatic dihydrazide such as isophthalic dihydrazide as essential components.
A cross-linked, supported polybenzimidazole membrane for gas separation is prepared by reacting polybenzimidazole (PBI) with the sulfone-containing crosslinking agent 3,4-dichloro-tetrahydro-thiophene-1,1-dioxide. The cross-linked reaction product exhibits enhanced gas permeability to hydrogen, carbon dioxide, nitrogen, and methane as compared to the unmodified analog, without significant loss of selectivity, at temperatures from about 20 degrees Celsius to about 400 degrees Celsius.
A cross-linked, supported polybenzimidazole membrane for gas separation is prepared by layering a solution of polybenzimidazole (PBI) and .alpha.,.alpha.'dibromo-p-xylene onto a porous support and evaporating solvent. A supported membrane of cross-linked poly-2,2'-(m-phenylene)-5,5'-bibenzimidazole unexpectedly exhibits an enhanced gas permeability compared to the non-cross linked analog at temperatures over 265.degree. C.
This invention relates to a method of an apparatus and method for separating component gases in a gas mixture employing a glassy polymer membrane at temperatures at or slightly above the freezing point of any liquid present so as to achieve superior separator of gas components. The composition of certain monomers and polymers are claimed.
