摘要:
In a continuous flow reactor one or more bisphenols is converted by the action of phosgene and aqueous base into a mixture of mono- and bisphenol chloroformates which are then treated with a catalyst, additional aqueous caustic and a monophenol to afford endcapped polycarbonates. At relatively high levels of added monophenol endcapped polycarbonate oligomers are obtained. The method is especially suited for the continuous preparation of endcapped oligomers of tetrabromobisphenol A polycarbonate. The method is characterized by efficient use of phosgene, and conversion of chloroformate groups to carbonate linkages aided by trialkylamine catalysts bearing at least one methyl group on nitrogen, such as N,N-dimethylbutylamine (DMBA).
摘要:
Hexasubstituted guanidinium chlorides are prepared by a method which affords them in high yield as aqueous solutions, optionally also containing alkali metal chlorides. The solutions may be employed as sources of hexasubstituted guanidinium salts useful as phase transfer catalysts for the reaction of alkali metal salts of dihydroxyaromatic compounds with substituted imides to form polyetherimides or their intermediates.
摘要:
Copolyetherimides 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:
Diaminoalkyl quaternary ammonium salts are prepared by the reaction of alkyl halides with tertiary diamines having C.sub.2-20 primary alkyl radicals attached to nitrogen and an alkyl radical between the two nitrogen atoms in which at least three carbon atoms separate said nitrogen atoms. Said salts are preferably substantially free from corresponding diamines. They are useful as catalysts for interfacial polycarbonate preparation by the reaction of phosgene with at least one dihydroxyaromatic compound. Polycarbonate preparation using such catalysts is economical in phosgene consumption, is accompanied by a rapid conversion of chloroformate groups to desirable species and affords a product with a very low proportion of unreacted dihydroxyaromatic compound.
摘要:
Reaction mixtures prepared from tetraalkyl titanates and mixtures of glycols, said reaction mixtures comprising titanium bisglycoxide oligomers, may be used as depolymerization catalysts for conversion of linear polyesters to macrocyclic polyester oligomers.
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-C12 aliphatic radical, C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; n, m, q are independently at each occurrence integers from 0 to 4; and Q is a C3-C20 cycloaliphatic radical, or a C3-C20 aromatic 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-C12 aliphatic radical, C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; n, m, q are independently at each occurrence integers from 0 to 4; and Q is a C3-C20 cycloaliphatic radical, or a C3-C20 aromatic radical.
摘要:
A separation matrix comprises a porous surface layer; and a bulk porous support, wherein both the porous surface layer and the bulk porous support comprising a block copolymer. The block copolymer comprises A-B or A-B-A repeating units, wherein A and B at each occurrence are two different blocks of oligomer, or polymer. A structural unit of block A is derived from one or more atom transfer radical polymerization (ATRP)-active monomer or oligomer and a structural unit of block B is derived from a thermoplastic ATRP-active macro initiator. A poly dispersity index of the block copolymer is at least about 2.
摘要:
Copolyetherimides compositions having high glass transition temperatures and outstanding ductility are presented. The copolyetherimides having Mw of at least 40,000 comprising isomeric bis(phthalimide) structural units within a relatively narrow range of isomer proportions exhibited Tgs of at least 240° C. and outstanding Notched Izod values. The copolyetherimides comprise oxydianiline residues and structural units of the formulas (I) and (II) (III). The copolyetherimides are characterized by a mole percentage of structural units derived from 4,4′-biphenol in a range from about 55% to about 85% of all bisphenol-derived structural units present in the copolyetherimide composition; a mole percentage of structural units derived from bisphenol A in a range from about 45% to about 15% of all bisphenol-derived structural units present in the copolyetherimide composition; and a total mole percentage of structural units derived from bisphenol A or 4,4′-biphenol of at least 95% of all bisphenol-derived structural units present in the copolyetherimide composition.
摘要:
The present invention provides carboxy-terminated oligomeric polyester compositions useful in the preparation of “weatherable” polymeric materials, for example weatherable copolyestercarbonates. In one aspect the present invention provides an oligomeric polyester composition comprising structural units derived from at least one diacid, at least one diaryl carbonate and at least one diol. The structural units derived from the diacid are present in a molar excess of from about 10% to about 40% based on a ratio of moles of diacid-derived structural units to moles of diol-derived structural units present in the oligomeric polyester composition. The oligomeric polyester composition is further characterized by the presence of at least some phenoxy end groups.