Synthesis and characterization of novel optically active poly(amide-imide)s via direct amidation

N,N′-Pyromelliticdiimido-di-l-methionine (3) was prepared from the reaction of pyromellitic dianhydride (1) with l-methionine (2) in glacial acetic acid and pyridine solution at refluxing temperature. The direct polycondensation reaction of the monomer diimide-diacid (3) with 1,3-phenylenediamine (4a), 1,4-phenylenediamine (4b), 2,6-diaminopyridine (4c), 3,5-diaminopyridine (4d), 4,4′-diaminodiphenylether (4e) and 4,4′-diaminodiphenylsulfone (4f) was carried out in a medium consisting of triphenyl phosphate, N-methyl-2-pyrolidone, pyridine and calcium chloride. The resulting poly(amide-imide)s having inherent viscosities 0.45-0.53 dl g⁻¹ were obtained in high yields and are optically active and thermally stable. All of the above compounds were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of these new optically active poly(amide-imide)s are reported.     

Synthesis and properties of novel poly(amide-imide)s containing pendent diphenylamino groups

A new dicarboxylic acid, 2,4-bis(N-trimellitoyl)triphenylamine, bearing two preformed imide rings was synthesized from the condensation of 2,4-diaminotriphenylamine and trimellitic anhydride at 1:2 molar ratio. A series of poly(amide-imide)s (PAIs) with inherent viscosities of 0.38-0.66 dl/g were prepared by triphenyl phosphite-activated polycondensation from the diimide-dicarboxylic acid with various aromatic diamines. All the resulting PAIs were readily soluble in a variety of organic solvents and formed strong and tough films via solution casting. These PAIs have useful levels of thermal stability associated with moderately high glass-transition temperatures (259-314 °C) and 10% weight loss temperatures in excess of 530 °C in nitrogen or in air.     

Novel heat-resistant and organosoluble poly(amide-imide)s containing laterally-attached phenoxy phenylene groups

In this research a new diimide-diacid monomer, 2,2′-bis(4-phenoxyphenyl)-4,4′-bis(N-trimellitoyl)diphenyl ether (BPDPE) containing two laterally-attached phenoxy phenylene groups was prepared by the reaction of 2,2′-bis[(p-phenoxy phenyl)]-4,4′-diaminodiphenyl ether (PPAPE) with trimellitic anhydride in refluxing glacial acetic acid. Ether-hinged wholly aromatic poly(amide-imide)s with limited viscosity number values of 0.61–0.87 dL g⁻¹ were prepared by triphenyl phosphate (TPP)-activated polycondensation of BPDPE with diamines including PPAPE and 4,4′-diaminodiphenyl ether (DADPE). For comparative purposes, reference poly(amide-imide)s were also prepared by reacting diimide-diacid monomer lacking phenoxy phenylene lateral groups namely 4,4′-bis(N-trimellitoyl)diphenyl ether (BTDPE) with the same diamines under similar conditions. A model compound MODEL was also synthesized by the reaction of BTBPE with two mole equivalents of aniline to compare the spectral characteristics results. Number and weight average molecular weights were determined by gel permeation chromatography (GPC) technique. The phenoxy phenylene-containing poly(amide-imide)s (all, except that of resulted from BTDPE and DADPE) had excellent organosolubility in common polar solvents. A low crystallinity extent was only observed using their wide-angle X-ray diffractograms (WAXD). A qualitative study showed the prepared polymers could also be cast into optically-transparent and flexible thin films. The ether-containing lateral groups attached to the ether-hinged macromolecular main chains had no substantial diminishing effect on the thermal stability of these structurally-modified poly(amide-imide)s.     

Rapid synthesis of optically active poly(amide-imide)s by direct polycondensation of aromatic dicarboxylic acid with aromatic diamines

4,4^′-(Hexafluoroisopropylidene)-N,N^′-bis(phthaloyl-l-leucine-p-amidobenzoic acid) (2) was prepared from the reaction of 4,4^′-(hexafluoroisopropylidene)-N,N^′-bis(phthaloyl-l-leucine) diacid chloride with p-aminobenzoic acid. The direct polycondensation reaction of monomer (2) with p-phenylenediamine (2a), 4,4^′-diaminodiphenylsulfone (2b), 2,4-diaminotoluene (2c), 2,6-diaminopyridine (2d), m-phenylene diamine (2e), benzidine (2f), 4,4^′-diaminodiphenylether (2g) and 4,4^′-diaminodiphenyl methane (2h) was carried out in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone, pyridine, and calcium chloride. The homogeneous mixture was heated at 220 °C for 1 min under nitrogen. The resulting poly(amide-imide)s (PAIs) having inherent viscosities 0.27-0.78 dl/g were obtained in high yield and are optically active and thermally stable. All of the above polymers were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of this new optically active PAIs are reported.     

Synthesis and characterization of optically active poly(amide-imide)s containing photosensitive chalcone units in the main chain

<正>A series of new optically active poly(amide-imide)s were synthesized by direct polycondensation reaction of 4,4'-diaminochalcone with several N-trimellitylimido-L-amino acids using a tosyl chloride(TsCl),pyridine(Py) and dimethylformamide(DMF) system as condensing agent.The resulting thermally stable poly(amide-imide)s were obtained in good to high yields and inherent viscosities ranging between 0.35 dL/g and 0.58 dL/g and were characterized with FTIR, ~1H-NMR,CHN,Ultraviolet,TGA and DTG techniques.     

Synthesis and characterization of new optically active and organosoluble poly(ester-imide)s based on bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide by direct polycondensation

New optically active poly(ester-imide)s PEIs were prepared from newly synthesized N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-isoleucine diacid 4 via direct polycondensation with various aromatic diols in a system of tosyl chloride (TsCl), pyridine (Py), and N,N-dimethylformamide (DMF). The reactions with bicyclo TsCl were significantly promoted by controlling alcoholysis with diols, in the presence of catalytic amounts of DMF, to give a series of optically active PEIs, with good yield and ...     

Synthesis of aromatic poly(amide-imide)s from novel diimide-diacid (DIDA) containing sulphone and bulky pendant groups by direct polycondensation with various diamines

A novel diimide-diacid (DIDA) monomer, 4-{4-[(4-methyl phenyl) sulphonyl]}-1,3-bis-trimellitoimido benzene containing sulphone and bulky pendant groups was successfully synthesized and used to synthesize a series of wholly aromatic poly(amide-imide)s (PAIs) by direct polycondensation method. The direct polycondensation of newly synthesized DIDA with different diamines was carried out via Yamazaki’s phosphorylation method using triphenyl phosphite and pyridine system. The resulting poly(amide-imide)s were obtained in quantitative yields with inherent viscosities 0.36-0.47 dl/g in DMAc at 30 ± 0.1 °C. The poly(amide-imide)s were amorphous and were readily soluble in various solvents such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), and pyridine. Tough and flexible films were obtained by casting their DMAc solution. According to thermogravimetric analysis, the polymers were fairly stable up to temperature around 396 °C, and 10% weight losses in the temperature range of 476-511 °C that showed good thermal stabilities of these polymers.     

Synthesis and characterization of novel poly(amide-imide)s containing hexafluoroisopropylidene linkage

A series of novel soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[N-(4-carboxyphenyl)-phthalimidyl]hexafluoropropane, with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl₂ using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.78–1.63 dL g⁻¹. The polymers were amorphous and readily soluble in aprotic polar solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide as well as in less polar solvents such as pyridine and γ-butyrolactone, and also in tetrahydrofuran. The polymer films had tensile strength of 84–129 MPa, an elongation at break range of 6–22%, and a tensile modulus range of 2.0–2.7 GPa. The glass transition temperatures of the polymers were determined by DSC method and they were in the range of 240–282°C. These polymers were fairly stable up to a temperature around or above 400°C, and lose 10% weight in the range of 450–514°C and 440–506°C in nitrogen and air, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2629–2635, 1999     

Preparation and characterization of novel organosoluble and thermally stable poly(benzimidazole-amide)s bearing phthalimide pendent groups

Novel aromatic poly(benzimidazole-amide)s, PBAs, have been synthesized by direct polycondensation of a new dicarboxylic acid, N-[3,5-bis(5-carboxylic acid-2-benzimidazole) phenyl]phthalimide (1), containing performed benzimidazole rings and a phthalimide pendent group with various aromatic diamines. The dicarboxylic acid was synthesized by reaction of 5-(N-phthalimide)isophthalic acid with 4-methyl-1,2-phenylenediamine in polyphosphoric acid, followed by its oxidation into relative dicarboxylic acid. To study the structure-property relationships of 1,3-bis(5-carboxylic acid-2-benzimidazole)benzene (2, as a reference) this compound was also synthesized. The chemical structure of 1 and 2 were confirmed by the spectroscopic methods and elemental analyses. The characterization of the polymers was performed with inherent viscosity measurements, solubility tests, FT-IR, Ultraviolet and ¹H NMR spectroscopy and thermogravimetry. The polymers were obtained in quantitative yields with inherent viscosities between 0.53 and 0.91 dl g⁻¹. The effects of the phthalimide pendent group on the polymer properties such as solubility and thermal behavior were investigated and compared with those of the corresponding unsubstituted poly(benzimidazole-amide)s. The modified poly(benzimidazole-amide)s showed enhanced solubilities in some solvents, such as m-cresol and pyridine, in comparison to the unmodified analogues. In addition, the incorporation of the pendent phthalimide groups in the poly(benzimidazole-amide)s backbone increased remarkably the thermal stability of the polymer. The glass transition temperature and 10% weight loss temperature of the poly(benzimidazole-amide)s were in range of 291-334 °C and 466-540 °C, respectively, in nitrogen.     

Novel optically active poly(amide-imide)s derived from L-aspartic acid

2,6-Bis-(2,5-dioxo-tetrahydro-N-(4-carboxyphenyl)pyrrol-3-yl)-pyrrolo[3,4-f]isoindole-1,3,5,7-teraone, a chiral diacid, was prepared from pyromellitic anhydride and L-aspartic acid in a three steps reaction pathway. The polycondensation reactions of the monomer with aromatic diamines were carried out in direct condensation reaction conditions. The synthesized poly(amide-imide)s had inherent viscosities in the range of 0.30–0.80 dl/g. Identification of all of the products were performed by conventional analytical techniques such as TLC, IR and ¹H NMR/¹³C MR spectroscopy. Thermoanalytical techniques (TGA/DSC) showed useful levels of thermal stability, associated with relatively high glass transition temperatures and carbonized residues in excess of 40% at 600°C for the synthesized polymers. Amorphous morphology was obtained based on XRD patterns and DSC traces. The polymers were soluble in a variety of polar organic solvents and afforded transparent and relatively flexible to brittle films by solution casting.     

Synthesis and characterization of poly(amideimide)s containing pendent flexible alkoxy chains

A series of aromatic diacylhydrazides containing pendent flexible alkoxy chains, viz., 5-butyloxyisophthalicacid dihydrazide, 5-octyloxyisophthalicacid dihydrazide, 5-dodecyloxyisophthalicacid dihydrazide and 5-hexadecyloxyisophthalicacid dihydrazide were synthesized by the hydrazinolysis reaction of the corresponding aromatic esters with hydrazine hydrate. Diacylhydrazides were each polycondensed with aromatic dianhydrides, viz., 4,4′-oxydiphthalic anhydride (ODPA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) to obtain new poly(amideimide)s. Poly(amideimide)s had inherent viscosity in the range 0.55-0.88 dL/g in N,N-dimethylacetamide (DMAc) at 30 ± 0.1 °C. Poly(amideimide)s were found to be soluble in DMAc, N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone (NMP) and pyridine and could be cast into tough, flexible and transparent films from a solution in DMAc. X-ray diffractograms revealed that poly(amideimide)s with longer alkoxy chains had layered structures. Glass transition temperature of poly(amideimide)s containing pendent flexible alkoxy chains were in the range 215-245 °C. Temperature at 10% weight loss was in the range 380-410 °C in nitrogen atmosphere indicating good thermal stability of poly(amideimide)s.     

Preparation of copoly(amide-imide)s via direct polycondensation

Preparation of various kinds of copoly(amide-imide) was carried out via direct polycondensation of trimellitic anhydride (TMA) with the corresponding diamine mixture in the presence of an equimolar amount of thionyl chloride (TC) as a condensing agent followed by thermal imidization. The resulting copoly(amide-imide)s had inherent viscosities in the range of 41 to 68 mL g⁻¹ and glass transition temperatures of 215°C to 291°C. These copoly(amide-imide)s had relatively good thermomechanical properties. That is, the initial decomposition temperature (IDT) and tensile strength were 350–409°C and 104–121 MPa, respectively. The melt viscosities of the copoly(amide-imide)s measured at 345°C under a frequency of 10² rad s⁻¹ were in the range of 4.8 × 10² ∼ 4.5 ˜ 10³ Pa s depending on comonomers, which are somewhat lower than that commerciallized PAI with 5.6 × 10³ Pa s.     

Self-Crosslinkable poly(arylene ether)s containing pendent phenylenetriazene groups

Self-crosslinkable poly(arylene ether)s 6 , and 8 , containing pendent triazene groups were prepared by nucleophilic substitution reaction of poly(arylene ether)s 5 , and 7 , respectively, with 1-[4-(4-hydroxyphenoxy)phenylene]triazenes, 4 , in the presence of potassium carbonate in N,N-dimethylacetamide. A series of triazenes 4 containing various substituents have been synthesized. Self-crosslinkable polymer 6e containing phenyl-substituted triazene pendants can be crosslinked at 215°C, which is about 40°C lower than the glass transition temperature of the virgin base polymer 5 . The degree of crosslinking can be tailored by varying the concentration of the pendent phenylenetriazene groups in the polymer. After curing, the flexible polymer films (ca. 10 μm thick) exhibit high gel contents, increased glass transition temperatures, improved resistance to organic solvents, and little change in dielectric constant and thermal stability. These self-crosslinkable poly(arylene ether)s are potential candidates for electronic applications. © 1994 John Wiley & Sons, Inc.     

Microwave-assisted rapid synthesis of novel optically active poly(amide-imide)s containing hydantoins and thiohydantoins in main chain

Rapid and highly efficient synthesis of novel optically active poly(amide-imide)s (PAIs) 6(a-f) was achieved using microwave irradiation. These were made from the polycondensation reactions of 4,4^′-carbonyl-bis(phthaloyl-l-alanine) diacid chloride [N,N^′-(4,4^′-carbonyldiphthaloyl)] bisalanine diacid chloride 5 with six different derivatives of hydantoin and thiohydantoin compounds 4(a-f) in the presence of a small amount of a nonpolar organic medium that acts as a primary microwave absorber. Hydantoin and thiohydantoin derivatives 4(a-e) were synthesis from the reactions between benzil or benzil derivatives 3(a-e) with urea and thiourea. 5,5-Dimethylhydantoin 4f was synthesis from the reactions between acetone cyanohydrin 3f and ammonium carbonate. The polycondensation proceeded rapidly, and was completed within 10 min giving a series of PAIs with an inherent viscosity about 0.25-0.45 dL/g. The resulting PAIs 6(a-f) were obtained in a high yield and were optically active and thermally stable. All of the above compounds were fully characterized by means of Fourier transform infrared spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility tests and specific rotation. Thermal properties of the PAIs 6(a-f) were investigated using thermal gravimetric analysis.     

Regularly alternating poly(amideimide)s containing pendent pentadecyl chains: Synthesis and characterization

Two new aromatic diamines containing preformed amide linkages, viz., N,N′-(4-pentadecyl-1,3-phenylene)bis(4-aminobenzamide) I and N,N′-(4-pentadecyl-1,3-phenylene)bis(3-aminobenzamide) II, were synthesized by reaction of 4-pentadecylbenzene-1,3-diamine with 4-nitrobenzoylchloride and 3-nitrobenzoylchloride, followed by reduction of the respective dinitro derivatives. A series of new poly(amideimide)s was synthesized by polycondensation of I and II with four commercially available aromatic dianhydrides, viz., pyromellitic dianhydride (PMDA), 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4′-oxydiphthalic anhydride (ODPA), and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) in N,N-dimethylacetamide (DMAc) employing conventional two step method via poly(amic acid) intermediate followed by thermal imidization. Reference poly(amideimide)s were synthesized by polycondensation of N,N′-(1,3-phenylene)bis(4-aminobenzamide) and N,N′-(1,3-phenylene)bis(3-aminobenzamide) with the same aromatic dianhydrides. Inherent viscosities of poly(amideimide)s containing pendent pentadecyl chains were in the range 0.37-1.23 dL/g in N,N-dimethylacetamide at 30 ± 0.1 °C indicating the formation of medium to high molecular weight polymers. The poly(amideimide)s containing pendent pentadecyl chains were found to be soluble in N,N-dimethylacetamide, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and pyridine and could be cast into transparent, flexible and tough films from their N,N-dimethylacetamide solution. Wide angle X-ray diffraction patterns exhibited broad halo indicating that the polymers were essentially amorphous in nature. X-ray diffractograms also displayed sharp reflection in the small angle region (2θ ≈ 3°) for poly(amideimide)s containing pentadecyl chains indicating the formation of layered structure arising from packing of flexible pentadecyl chains. The glass transition temperatures observed for reference poly(amideimide)s were in the range 331-275 °C and those for poly(amideimide)s containing pendent pentadecyl chains were in the range 185-286 °C indicating a large drop in T_g owing to the “internal plasticization” effect of pentadecyl chains. The temperature at 10% weight loss (T₁₀), determined by TGA in nitrogen atmosphere, were in the range 460-480 °C indicating their good thermal stability.     

The synthesis and characterization of a poly(maleimide-ether) containing pendent thiophene rings

The preparation of a poly(maleimide-ether) containing pendent thiophene rings via the reaction of 2-(3-thienylmethyl)-1,3-N,N'-bis(3,4-dichloromaleimido) propane with 1,4-dihydroxybenzene is described. The novel 2-substituted-1,3-N,N'-bis(3,4-dichloromaleimido) propanes were obtained by allowing their corresponding diamine hydrochlorides to react with 3,4-dichloromaleic anhydride in acetic acid in the presence of sodium methoxide. The diamine hydrochlorides were prepared by the reduction of their respective diamides. The poly(maleimide-ether)s were fully characterized and ¹³C-NMR spectroscopy was used to confirm the microstructure of the materials. The properties of the thiophene substituted polymer are compared with model poly(maleimide-ether)s. Electrochemical studies indicated that the thiophene rings in the thiophene-substituted poly(maleimide-ether) were not electroactive. © 1992 John Wiley & Sons, Inc.     

New poly(amide-imide) siloxane copolymers by polycondensation

Some new poly(amide-imide) siloxane copolymers have been synthesized by solution polycondensation of some aromatic diamines with siloxanic diacids having preformed imide rings. Two polycondensation techniques were used: polycondensation of aromatic diamines with diacid chlorides and direct polycondensation of aromatic diamines with diacids in the presence of organic phosphites, following the Yamazaki-Higashi phosphorylation technique. In all cases the reactions were carried out using equimolecular amounts of the two monomers, in polar aprotic solvents and inert atmosphere.The obtained compounds were characterized by elemental C, H and Si analysis, solubility tests, IR and ¹H-NMR spectrometry. Thermogravimetric curves were also recorded. All data agree with the proposed structures.     

Preparation and characterization of new thermally stable and optically active poly(ester‐imide)s by direct polycondensation with thionyl chloride in pyridine

4,4′‐hexafluoroisopropylidene‐2,2‐bis‐(phthalic acid anhydride) (1) was reacted with L ‐methionine (2) in acetic acid and the resulting N,N′–(4,4′‐hexafluoroisopropylidenediphthaloyl)‐bis‐L ‐methionine (4) was obtained in high yield. The direct polycondensation reaction of this diacid with several aromatic diols such as bisphenol A (5a), phenolphthalein (5b), 1,4‐dihydroxybenzene (5c), 4,4′‐dihydroxydiphenyl sulfide (5d), 4,6‐dihydroxypyrimidine (5e), 4,4′‐dihydroxydiphenyl sulfone (5f) and 2,4′‐dihydroxyacetophenone (5g) was carried out in a system of thionyl chloride and pyridine. Expecting that the reaction with thionyl chloride in pyridine might involve alternative intermediates different from an acyl chloride, the polycondensation at a higher temperature favorable for the reaction of the expected intermediate with nucleophiles was attempted, and a highly thermally stable poly(ester‐imide) was obtained by carrying out the reaction at 80°C. All of the above polymers were fully characterized by ¹H‐NMR, ¹⁹F‐NMR FT‐IR spectroscopy, elemental analysis and specific rotation. Some structural characterization and physical properties of these optically active poly(ester‐ imide)s are reported. Copyright © 2006 John Wiley & Sons, Ltd.     

Preparation and characterization of poly(amide-imide)/ZnO nanocomposites containing pendent benzoxazole and benzimidazole segments

In the present investigation, novel poly(amid-imide)/zinc oxide nanocomposites (PAI/ZnO NCs) containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles (ZnO NPs) were successfully prepared via the ex situ method. Poly(amid-imide) (PAI) was prepared by direct polycondensation of 2-[3,5- bis(N-trimellitimidoyl)phenyl]benzoxazole (DCA) with 5-(2-benzimidazole)-1,3-phenylenediamine (DAMI) and provided the polymeric matrix with well-designed groups. The surface of ZnO NPs was functionalized with 3-aminopropyltriethoxysilane (APS) coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the ZnO surface was determined by thermogravimetric analysis. PAI/ZnO nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). SEM analysis showed that the modified ZnO nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.     

Synthesis,characterization, and chiroptical property of optically active poly(urea-urethane)s

Five new optically active poly(urea-urethane)s were synthesized by solution polyaddition of (1S,2S)-(+)-2-amino-3-methoxy-1-phenyl-1-propanol ( 4 ) with diisocyanates (diphenylmethane-4,4′-diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate) at 80°C for 60 h. In some cases, the reaction mixture transformed into a gel when cooled to room temperature. The reduced viscosities are between 0.14 and 0.63 dL/g depending on the solvents and diisocyanates. Thermal behaviors of these polymers were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The T_g and crystallization temperature (T_c) were in the range of 80–200°C and 220–238°C, respectively. Thermal decomposition started at about 275°C, and the residual weights at 400°C were 15–60% depending on the polymers. The conformation of the polymers in film state was studied by circular dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or propyl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic diisocyanates did not. After packing as chiral stationary phases of high-performance liquid chromatography (HPLC), the polymers showed selective resolution to trans-stilbene oxide and trans-1,2-cyclopentanedicarboxanilide. © 1993 John Wiley & Sons, Inc.