Synthesis and characterization of polyamides containing arylene sulfide-sulfone groups

Polyamides containing arylene sulfide as well as arylene sulfide-sulfone linkages were prepared from bis(4-phenylthio)dibenzoyl chloride (BPCl), 4,4′-[sulfonylbis(4-phenylthio)]dibenzoyl chloride (SPCl) and aromatic diamines both by solution and interfacial polymerization techniques. In the solution polymerization the effect of two different acid acceptors, lithium chloride and triethylamine, on inherent viscosity of the polyamides was studied. The effect of aromatic sulfone ether diamines and conventional aromatic diamines on viscosity and thermal properties of polyamides was also investigated. The polyamides prepared were characterized by IR, ¹H NMR, elemental analysis, solution viscosity, thermogravi-metry, differential scanning calorimetry and X-ray diffraction. Thermal and physical properties of polyamides prepared from BPCl and SPCl were compared.     

Aromatic polyesters (polyarylates) containing arylene sulfone ether linkages

A series of soluble aromatic polyesters (polyarylates) containing arylene sulfone ether linkages and having inherent viscosities of 0.36–1.10 dl/g were prepared by the two-phase low temperature polycondensation of 4,4′-[sulfonyl-bis(p-phenyleneoxy)]dibenzoyl chloride and 3,3′-[sulfonylbis(p-phenyleneoxy)]-dibenzoyl chloride with various bisphenols in an organic solvent-aqueous alkaline solution system in the presence of a phase transfer catalyst. Bisphenols 4,4′-[sulfonylbis(p-phenyleneoxy)]diphenol and 3,3′-[sulfonylbis(p-phenyleneoxy)]-diphenol were synthesized in quantitative yields by an improved procedure. The aromatic polyesters prepared were characterized by infrared spectroscopy, elemental analysis, solution viscosity, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction. The polyesters prepared had glass transition temperatures in the range 150–230°C and initial decomposition temperatures of 397–491°C. They gave transparent, tough and flexible films by the solution casting technique.     

Synthesis and properties of novel polyamides containing sulfone‐ether linkages and xanthene cardo groups

In order to obtain polyamides with enhanced solubility and processability, as well as good mechanical and thermal properties, several novel polyamides containing sulfone‐ether linkages and xanthene cardo groups based on a new diamine monomer, 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX), were investigated. The BAPX monomer was synthesized via a two‐step process consisting of an aromatic nucleophilic substitution reaction of readily available 4‐chloronitrobenzene with 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Four novel aromatic polyamides containing sulfone‐ether linkages and xanthene cardo groups with inherent viscosities between 0.98 and 1.22 dL g^?1 were prepared by low‐temperature polycondensation of BAPX with 4,4′‐sulfonyldibenzoyl chloride, 4,4′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride, 3,3′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride and 4,4′‐[sulfonyl‐bis(2,6‐dimethyl‐1,4‐phenyleneoxy)]dibenzoyl chloride in N,N‐dimethylacetamide (DMAc) solution containing pyridine. All these new polyamides were amorphous and readily soluble in various polar solvents such as DMAc and N‐methylpyrrolidone. These polymers showed relatively high glass transition temperatures in the range 238–298 °C, almost no weight loss up to 450 °C in air or nitrogen atmosphere, decomposition temperatures at 10% weight loss ranging from 472 to 523 °C and 465 to 512 °C in nitrogen and air, respectively, and char yields at 800 °C in nitrogen higher than 50 wt%. Transparent, flexible and tough films of these polymers cast from DMAc solution exhibited tensile strengths ranging from 78 to 87 MPa, elongations at break from 9 to 13% and initial moduli from 1.7 to 2.2 GPa. Primary characterization of these novel polyamides shows that they might serve as new candidates for processable high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of polyamides and poly(amide-imide)s based on ether-sulfone-diamines

A series of polyamides and poly(amide-imide)s were prepared by the direct polycondensation of 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline or 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenyleneoxy)]dianiline with aromatic dicarboxylic acids and phthalimide unit-bearing dicarboxylic acids in a N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing agents. The inherent viscosities of the resulting polymers were above 0.45 dL/g and up to 1.70 dL/g. Except for the polyamides derived from terephthalic acid and 4,4′-biphenyldicarboxylic acid, all the other polyamides and all poly(amide-imide)s were readily soluble in polar organic solvents such as NMP, N, N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and m-cresol, and afforded transparent and tough films by solution-casting. Most of the polymers showed distinct glass transition on their differential scanning calorimetry (DSC) traces and their glass transition temperatures (T_g) stayed between 140–264 °C. The methyl-substituted polymers showed higher T_gs than the corresponding unsubstituted counterparts. The results of the thermogravimetry analysis (TGA) revealed that all the methyl-substituted polymers showed lower initial decomposition temperatures than the unsubstituted ones.     

Syntheses of functional condensation polymers. II. A polyamide having epoxy groups and its ring-opening derivatives

Polyamides having epoxy groups and their ring-opening derivatives were prepared and characterized, and some of their properties were investigated. Reaction conditions for the low-temperature polycondensation of cis-2,3-epoxysuccinyl chloride (ESC) with aromatic diamines and the interfacial copolycondensation of ESC and adipyl chloride (AC) with aromatic diamines were established to obtain a high molecular weight polyamide having epoxy groups. In addition, the ring-opening reactions of the epoxy groups in the polyamides were carried out with various amines in order to obtain polyamides having hydrophilic pendent groups such as amino and hydroxyl. It was found that the polyamides prepared by ring-opening reaction of the epoxy group with ethylenediamine (EDA) or ethanolamine (EA) had a higher affinity for moisture than those with hexamethylenediamine (HMD) or n-butylamine (n-BA), which might be ascribed to the distance of hydrophilic groups from the polyamide chain. Those polyamides having hydrophilic pendent groups decomposed upon heating at less than 200°C.     

Aromatic polyamides bearing ether and isopropylidene or hexafluoroisopropylidene links in the main chain

Two multiring, flexible dicarboxylic acids, 4,4'-[isopropylidenebis(1,4-phenylene)dioxy] dibenzoic acid (3) and 4,4'-[hexafluoroisopropylidenebis(1,4-phenylene)dioxyldibenzoic acid (3-F), were synthesized through the nucleophilic fluorodisplacement ofp-fluorobenzonitrile by the dipotassium bisphenolates of the corresponding bisphenol precursors followed by alkaline hydrolysis. Two series of aromatic polyamides 5_a–k and 5_a–k-F containing both ether and isopropylidene or hexafluoroisopropylidene linkages between phenylene units were prepared by direct polycondensation of diacids 3 and 3-F, respectively, with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in aN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides of 5 and 5-F series have inherent viscosities of 0.92–1.29 dL/g and 0.60–0.92 dL/g, respectively. Most of these polymers are amorphous in nature, are soluble in polar solvents such as NMP,N,N-dimethylacetamide (DMAc), andN,N dimethylformamide (DMF), and can afford tough and flexible films by solution casting. Differential scanning calorimetry shows T_gs ranging from 175 to 239 °C for the 5 series polyamides and ranging from 172 to 267 °C for the 5-F series polymers. Both classes of polyamides show good thermal stability, with the 5-F series polyamides being more stable.     

Poly(amide-ester)s from p-aminobenzoic acid

Poly(amide-ester)s containing p-aminobenzoic acid derived from three different diols (1,6-hexanediol, 1,4-butanediol, and trans-1,4-cyclohexanedimethanol) and two different acid chlorides (sebacoyl and adipoyl chloride) were synthesized by melt polymerization. The thermal and viscoelastic behaviour has been investigated and related to the chemical composition. All of the polymers synthesized showed an inherent viscosity ranging from 0·26 to 0·47dlg^-1. The poly(amide-ester)s prepared by melt polymerization showed a lower molecular weight and melting temperature than polymers prepared by solution polymerization. The lower melting points of the polymers prepared by melt polymerization were due either to the lower molecular weight or to breakage of intermolecular hydrogen bonding, which was attributed to amide–ester exchange reactions during polymerization. © 1998 SCI.     

Synthesis and characterization of wholly aromatic polyamides containing pendent amino and cyano groups

The new pyrazole-ring containing diamine monomer with amino and cyano groups, 1,3-di-p-aminophenyl-4-cyano-5-aminopyrazole (PYA), was prepared from 4-nitrobenzoyl chloride and 4-nitrophenyl hydrazine with 4 steps. The monomer was converted to polyamides with terephthaloyl chloride and isophthaloyl chloride. The amino and cyano groups on the pyrazole-ring were not affected during polymerization. The synthesized polyamides having intrinsic viscosities of 0.92 – 1.18 dL/g were amorphous, and soluble in polar aprotic solvents and boiling acetone and THF. The polymers had high glass transition temperatures and high thermal stability. 5% weight loss temperatures in nitrogen occurred around 490 °C, but these polymers are partially degraded at 300 °C in air due to the amino group on the pyrazole-ring. Received: 6 March 1997/Accepted: 1 April 1997     

Synthesis and properties of novel aromatic polyamides with xanthene cardo groups

Two novel monomers, 9,9‐bis[4‐(4‐carboxyphenoxy)phenyl]xanthene (BCAPX) and 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX) were prepared in two main steps starting from nucleophilic substitution of 9,9‐bis(4‐hydroxyphenyl)xanthene (BHPX) with p‐fluorobenzonitrile and p‐chloronitrobenzene, respectively. Using triphenyl phosphite and pyridine as condensing agents, two series of polyamides containing xanthene cardo groups with the inherent viscosities (0.82–1.32 dL/g) were prepared by polycondensation from BCAPX with various aromatic diamines or from BAPX with various aromatic dicarboxylic acids in an N‐methyl‐2‐pyrrolidone (NMP) solution containing dissolved calcium chloride, respectively. All new polyamides were amorphous and readily soluble in various polar solvents such as N,N‐dimethylformamide (DMF), NMP, N,N‐dimethylacetamide (DMAc) and pyridine. These polymers showed relatively high glass transition temperatures between 264 and 308°C, decomposition temperatures at 10% weight loss ranging from 502 to 540°C and 488 to 515°C in nitrogen and air, respectively, and char yields at 800°C in nitrogen higher than 56%. Transparent, flexible, and tough films of these polymers cast from DMAc solutions exhibited tensile strengths ranging from 86 to 109 MPa, elongations at break from 13 to 22%, and initial moduli from 2.15 to 2.63 GPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of nylon 6,6 copolymers with aromatic polyamide structure

In this article, flexible nylon 6,6 was reinforced with rigid‐chain aromatic polyamides based on poly(4,4′‐diphenylsulfone terephthalamide) (PSA), poly(p‐diphenyl oxide terephthalamide) (POA), poly(p‐diphenylmethane terephthalamide) (PMA), and isophthaloyl chloride (IPC). Various high molecular weight block copolyamides were synthesized by solution polymerization using p‐aminophenylacetic acid (p‐APA) as a coupling agent. Their thermal properties show that the block copolyamides exhibit higher values of T_g and T_m and better thermal stability than those of nylon 6,6, especially the IPC‐modified nylon 6,6. The order of increased thermal properties of copolyamides is IPC > POA > PMA > PSA. From wide‐angle X‐ray diffraction patterns, it was found that nylon 6,6 has two diffraction peaks, that is, 2θ = 20.5° and 23°, while the multiblock copolymers showed only one at 2θ = 20°, indicating a different crystal structure. It was found that the mechanical properties of the IPC‐modified nylon 6,6 were improved more than those of the semirigid copolyamides. The order of tensile strength was IPC > PSA > PMA > POA, but for elongation, it was POA > PMA > PSA > IPC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2167–2175, 2001     

Preparation and characterization of new photoactive polyamides containing 4‐(4‐dimethylaminophenyl)urazole units

4‐(4‐dimethylaminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( DAPTD ) was prepared from 4‐dimethylaminobenzoic acid in five steps. The compound DAPTD was reacted with excess acetyl chloride in N,N‐dimethylacetamide (DMAc) solution and gave 1,2‐bisacetyl‐4‐[4‐(dimethylaminophenyl)]‐1,2,4‐triazolidine‐3,5‐dione as a model compound. Solution polycondensation reactions of monomer with succinyl chloride (SucC), suberoyl chloride (SubC), and sebacoyl chloride (SebC) were performed under conventional solution polymerization techniques in the presence of triethylamine and pyridine as a catalyst in N‐methylpyrrolidone (NMP) and led to the formation of novel aliphatic polyamides. These novel polyamides have inherent viscosities in the range of 0.09–0.21 dL/g in N,N‐dimethylformamide (DMF) at 25°C. Fluorimetric studies of the model compound as well as polymers were performed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 947–954, 2007     

Synthesis and characterization of novel aromatic polyamides derived from 2,2′‐bis(p‐phenoxyphenyl)‐4, 4′‐diaminodiphenyl ether

BACKGROUND: Wholly aromatic polyamides (aramids) are high‐performance polymeric materials with outstanding heat resistance and excellent chemical stabilities due to chain stiffness and intermolecular hydrogen bonding of amide groups. Synthesis of structurally well‐designed monomers is an effective strategy to prepare modified forms of these aramids to overcome lack of organo‐solubility and processability limitations. RESULTS: A novel class of wholly aromatic polyamides was prepared from a new diamine, namely 2,2′‐bis(p‐phenoxyphenyl)‐4,4′‐diaminodiphenyl ether (PPAPE), and two simple aromatic dicarboxylic acids. Two reference polyamides were also prepared by reacting 4,4′‐diaminodiphenyl ether with the same comonomers under similar conditions. M?_w and M?_n of the resultant polymers were 8.0 × 10⁴ and 5.5 × 10⁴ g mol^?1, respectively. Polymers resulting from PPAPE exhibited a nearly amorphous nature. These polyamides exhibited excellent organo‐solubility in a variety of polar solvents and possessed glass transition temperatures up to 200 °C. The 10% weight loss temperatures of these polymers were found to be up to 500 °C under a nitrogen atmosphere. The polymers obtained from PPAPE could be cast into transparent and flexible films from N,N‐dimethylacetamide solution. CONCLUSION: The results obtained show that the new PPAPE diamine can be considered as a good monomer to enhance the processability of its resultant aromatic polyamides while maintaining their high thermal stability. The observed characteristics of the polyamides obtained make them promising high‐performance polymeric materials. Copyright © 2009 Society of Chemical Industry     

Synthesis and properties of polyamides and copolyamides based on 2,6-naphthalene dicarboxylic acid

A number of polyamides based on 2,6-naphthalene dicarboxylic acid (NDA) and various aromatic diamines were synthesized in N-methyl pyrrolidone (NMP) containing lithium chloride (LiCl) or calcium chloride (CaCl₂) by direct polycondensation using triphenyl phosphite and pyridine. The best reaction conditions for polycondensation were determined in terms of factors such as the amount of the solvency-promoting reagent such as LiCl or CaCl₂ and the initial reactant concentration. Thus, almost all polyamides were obtained with inherent viscosities above 1.0 and up to 3.28 dL/g. Similarly, high molecular weight copolyamides with inherent viscosities of 1.76–3.61 dL/g were prepared from 4,4′-oxydianiline (ODA) and mixed dicarboxylic acids of NDA/terephthalic acid (TPA) or NDA/isophthalic acid (IPA). The solubility of NDA homopolyamides depended on the diamine components. The polyamides derived from meta-, sulfone-, or alkylene-linked diamine showed increased solubility. Copolymerization of ODA with NDA/IPA led to a significant increase in solubility, whereas with NDA/TPA, it gave a limited improvement. All the homopolyamides and copolyamides showed an amorphous X-ray diffraction pattern. Almost all the polymers soluble in aprotic solvents can be solution-cast into strong and tough films. Glass transition shifts of some NDA polyamides can be observed in the differential scanning calorimetry (DSC) curves ranging from 243 to 345°C. Most NDA/IPA–ODA copolyamides also showed clear transitions in the range of 255–268°C. In nitrogen, all the polymers showed no significant weight loss up to 400°C, and their 10% weight loss temperatures were recorded in the range of 434–541°C. © 1994 John Wiley & Sons, Inc.     

Synthesis,characterization, and study of thermal properties of methyl-substituted arylene sulfone ether polyimides,polyamides, and poly(amide–imides)

A number of methyl-substituted bis[(phenyleneoxy) sulfone] dianilines were synthesized and reacted with pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and trimellitic anhydride acid chloride (TMAC) to prepare a series of polyimides, polyamides, and poly(amide–imides), respectively. Low temperature solution and interfacial polymerization techniques were utilized to prepare the above polymers. Most of the polymers prepared formed tough, transparent flexible films. The prepared polymers were characterized by solution viscosity, thermal gravimetric analysis (dynamic and isothermal), and differential scanning calorimetry. The effect of the number and the ring substitution of methyl groups on polymer properties is discussed.     

New soluble polyamides and polyimides containing polar functional groups: pendent pyrazole rings with amino and cyano groups

A series of aromatic polyamides and polyimides containing pendent pyrazole rings with amino and cyano groups were prepared from a new monomer, 1-(2,4-diaminophenyl)-3-phenyl-4-cyano-5-aminopyrazole, which was prepared from (chloromethylene)propanedinitrile and 2,4-dinitrophenyl hydrazine with two steps. In addition, model compounds were synthesized and characterized by elemental analyses, Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The amino and cyano groups on the pyrazole ring were not affected during the polymerization process. The synthesized polymers, with intrinsic viscosities of 0.33–0.53 dL/g, were soluble in various organic solvents. They showed no T_g values before degradation, and the 5% weight loss temperature of the polyamides and the polyimides occurred at approximately 420 and 470 °C, respectively. They also underwent no thermal transitions, such as degradation or crosslinking, up to 440 °C in spite of the presence of pendent amino and cyano groups.     

Synthesis and properties of new polyamides based on a hydroxyethyl cinnamide extended from 3,5‐diaminobenzoic acid

A series of new aromatic polyamides containing cinnamide pendent units were prepared from 2′‐(cinnamide)ethyl‐3,5‐diaminobenzoate and various aromatic dicarboxylic acids by the direct polycondensation reaction, with triphenyl phosphite and pyridine as condensing agents. The polyamides were characterized by ¹H NMR, IR, and UV spectroscopy, and gel permeation chromatography. Their thermal stability was studied by thermogravimetric analysis in air, and differential scanning calorimetry. These polymers were readily soluble in polar aprotic solvents and can be cast from their solutions in flexible and tough films. Glass transition temperatures (T_gs) of these polyamides were observed in the range of 225–245°C. Their inherent viscosities varied from 0.77 to 1.12 dL/g that corresponded to weight–average and number–average molecular weights of 39,000–72,700 and 18,800–29,000, respectively. These polymers can be photochemically crosslinked. The photochemical aspects were revealed by means of UV–vis and IR analyses onto thin films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2013–2020, 2007     

Synthesis and properties of novel soluble polychloro substituted aromatic polyamides

A novel monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175–180°C for 10 h, and confirmed by FTIR, MS, and elemental analysis. A series of new polychloro substituted polyamides with inherent viscosities of 1.17–1.28 dL/g have been prepared from TCTPC with various aromatic diamines. All the polyamides were amorphous and readily soluble in polar solvents such as NMP, DMAc, DMF, and DMSO at room temperature, and could afford flexible and tough films via solution casting. The cast films exhibited good mechanical properties with tensile strengths of 83.6–106.8 MPa, elongations at breakage of 3.9–7.1%, and tensile modulus of 2.28–3.98 GPa. These polyamide films also exhibited good thermal stability with the glass transition temperature of 250–284°C, the temperature at 5% weight loss of 470–504°C and high char yields of 57.8–59.7% in nitrogen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Novel chalcone-based aromatic polyamides: synthesis,characterization, and properties

Two novel diacid-based monomers have been synthesized by anchoring a benzylideneacetophenone (chalcone) moiety through an amide or ester bridge at the fifth position of the isophthalic acid ring. Two series of new polyamides bearing chalcone side chains were prepared by direct polycondensation reaction of the aforementioned dicarboxylic acids and various aromatic diamines in N-methyl-2-pyrrolidinone, using triphenyl phosphite and pyridine as condensing agents. Their molecular structure and the basic properties were investigated by nuclear magnetic resonance, Fourier-transform IR and UV–vis spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction. The inherent viscosity, molecular weights measurements (by gel permeation chromatography), water uptake, and solubility tests completed the research study. Introduction of the rigid and bulky chalcone units into the polymer side chains improved remarkably the solubility of the aromatic polyamides, endowed them with an amorphous nature, good thermal stability, and photosensitivity. The resulting polymers were obtained in good yields, inherent viscosities varied between 0.49 and 0.86 dL/g, and their relative high molecular weights conferred them film-forming properties. They were soluble in amide-type polar solvents, such as N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. These polyamides had glass transition temperatures between 219 and 264 °C, and 10% weight loss temperatures in the range of 394–436 °C and around 50% residue at 700 °C in nitrogen atmosphere. The polyamides underwent a [2 + 2] photocycloaddition reaction upon UV light irradiation both in solution and film state in the absence of a photoinitiator or photosensitizer. The polymer films became insoluble in solvents as a result of the crosslinking .     

Influence of moieties on morphology,thermal, and dielectric properties in polyamide‐polyhedral oligomeric silsequioxanes nanocomposites

A series of new hexafluoroisopropylidene, isopropylidene, carbonyl, and ether moieties substituted polyamides have been prepared from aromatic diamines and various moieties substituted aromatic dianhydrides. The synthesized polyamides were readily soluble in polar solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. These polyamides exhibited good thermal stability and high char yields. The chemical and physical properties of the newly prepared polyamide‐polyhedral oligomeric silsequioxanes (PA‐POSS) were compared in terms of their chemical structures and thermal properties. The morphological properties of the polymeric nanocomposites depend both on their chemical structure of dianhydride and the aggregation of POSS were investigated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Polyamides with bulky POSS and ?uoro groups can effectively decrease dielectric constants. The dielectric constants of PA‐POSS were found to be decreased from 3.75 to 3.29 by changing the substitution. These polyamides showed good thermal stability up to 353 °C for a 10 % weight loss. The fluorinated polyamides have relatively higher thermal stability than the polyamides without halogen because of high bond energy of C? F bond. The fiuorinated groups in the polymer backbone have played an important role in the improvement of dielectric performance of polymers. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

A simple and efficient way to synthesize optically active polyamides by solution polycondensation of di‐O‐methyl‐L‐tartaryl chloride with diamines

A series of optically active polyamides containing di‐O‐methyl‐L ‐tartaryl moieties in the main chain were synthesized by polycondensation of di‐O‐methyl‐L ‐tartaryl chloride 5 with diamines and characterized by gel permeation chromatography, UV–vis, circular dichroism (CD), IR, and NMR spectroscopies. The polycondensation reaction could be carried out under mild conditions and the reaction time was short (2–3 h). The key monomer 5 prepared from L ‐tartaric acid via esterification, etherification, hydrolysis, and chlorination was easily purified by vacuum sublimation. These polyamides with number average molecular weights ranging from 14,000 to 35,000, displayed large optical activity in dimethyl sulfoxide solution, and their specific optical rotations oscillated between 87.2° and 210.7° depending on the structures of the diamines. The glass transition temperatures of these polyamides were in the range of 106–191°C, and the 10% mass loss occurred at temperature above 300°C. The polyamides derived from aromatic diamines exhibited higher T_g and thermal stability than those derived from aliphatic diamines. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010