摘要:
A membrane is provided, which may include a microporous base membrane; and a cross-linkable coating disposed on a surface of the membrane. The coating may include polyvinyl nucleophilic polymer and a urethane or a blocked isocyanate. The coating may be cross-linked. Also provided is a method of making the membrane.
摘要:
Methods of reducing the amount of undesirable cyclic oligomer by-products in the production of polyetherimides are disclosed. The resulting polyetherimides have enhanced thermomechanical properties.
摘要:
Poly(1,4-cyclohexanedicarboxylate)s, especially poly(1,4-cyclohexanedimethylene-1,4-cyclohexanedicarboxylate), are prepared from at least one relatively non-volatile diol, such as 1,4-cyclohexanedimethanol, and cyclohexane-1,4-dicarboxylic acid by an esterification process in the presence of a catalyst, at a maximum temperature of about 260°. In one embodiment the procedure employs a two-step process, the second of which may be performed in the melt or in the solid state. A volatile diol such as ethylene glycol may also be present.
摘要:
Oxydiphthalic anhydrides such as 4-oxydiphthalic anhydride are prepared by the reaction of a halophthalic anhydride with an alkali metal carbonate such as potassium carbonate in the presence of a catalyst system comprising an alkali metal bicarbonate such as potassium bicarbonate and a phase transfer catalyst, preferably a tetraarylphosphonium halide.
摘要:
Polycarbonates containing low or undetectable levels of Fries rearrangement product may be prepared by the melt reaction of a dihydroxy aromatic compound such as bisphenol A with an ester-substituted diaryl carbonate such as the diaryl carbonate of methyl salicylate, bis-methyl salicyl carbonate. Low levels of Fries product are obtained as the combined result of a highly effective catalyst system which suppresses the Fries reaction and the use of lower melt polymerization temperatures relative to temperatures required for the analogous polymerization reaction using diphenyl carbonate.
摘要:
Thermally stable polymers comprising resorcinol arylate chain members are prepared using an interfacial method comprising the steps of: (a) combining at least one resorcinol moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water; and (b) adding to the mixture from (a) at least one dicarboxylic acid dichloride while maintaining the pH between 3 and 8.5 through the presence of an acid acceptor, wherein the total molar amount of acid chloride groups is stoichiometrically deficient relative to the total molar amount of phenolic groups.
摘要:
Thermally stable polymers comprising resorcinol arylate chain members are prepared using an interfacial method comprising the steps of: (a) combining at least one resorcinol moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water; and (b) adding to the mixture from (a) at least one dicarboxylic acid dichloride while maintaining the pH between 3 and 8.5 through the presence of an acid acceptor, wherein the total molar amount of acid chloride groups is stoichiometrically deficient relative to the total molar amount of phenolic groups.
摘要:
Polyetherimides are prepared by conventional means from hindered diamines such as the isomeric methyl-4,6-diethyl-1,3-phenylenediamines and bis(2-chloro-4-amino-3,5-diethylphenyl)methane. They have unusually high glass transition temperatures.
摘要:
Polyethersulfones having Tg greater than about 225° C. and a notched Izod value greater than about 1 ft-lb/in, as measured by ASTM D256, comprise from about 5 mol % to less than about 40 mol % structural units of formula 1; and from greater than about 60 mol % to about 95 mol % structural units of formula 2 wherein R1, R2, and R3 are independently at each occurrence a halogen atom, a nitro group, a cyano group, a C1-C12aliphatic radical, C3-C12cycloaliphatic radical, or a C3-C12aromatic radical; n, m, q are independently at each occurrence integers from 0 to 4; and Q is a C3-C20cycloaliphatic radical, or a C3-C20aromatic radical.
摘要:
Polyethersulfones having Tg greater than about 225° C. and a notched Izod value greater than about 1 ft-lb/in, as measured by ASTM D256, comprise from about 5 mol % to less than about 40 mol % structural units of formula 1; and from greater than about 60 mol % to about 95 mol % structural units of formula 2 wherein R1, R2, and R3 are independently at each occurrence a halogen atom, a nitro group, a cyano group, a C1-C12aliphatic radical, C3-C12cycloaliphatic radical, or a C3-C12aromatic radical; n, m, q are independently at each occurrence integers from 0 to 4; and Q is a C3-C20cycloaliphatic radical, or a C3-C20aromatic radical.