Preparation and Characterization of New Optically Active Poly(amide imide)s Derived from N,N’-(4,4’-Sulphonediphthaloyl)-bis-(s)-(+)-valine Diacid Chloride and Aromatic Diamines under Microwave Irradiation

Summary The present paper is an extension of microwave method describing the synthesis of the new optically active poly(amide-imide)s. The main focus of this work is the design of new effective microwave method for preparing optically active poly(amide-imide)s. Imide-acid (3) was synthesized by the reaction of 3,3,4,4-diphenylsulfonetetracarboxylic dianhydride (1) with (s)-(+)-valine (2) in acetic acid. The compound 3 was coverted to diacid chloride 4 by reaction with excess amount of thionyl chloride. Polycondensetion reaction of diacid chloride 4 with several aromatic diamines such as 4,4-sulfonyldianiline (5a), 4,4-diaminodiphenyl methane (5b), 4,4-diaminodiphenylether (5c), p-phenylenediamine (5d), m-phenylenediamine (5e), 2,4-diaminotoluene (5f) and 4,4-diaminobiphenyl (5g) was carried out in the presence of small amount of o-cresol under microwave irradiation as well as conventional heating method. We obtained a series of optically active poly(amide-imide)s with high yield and inherent viscosity ranging from 0.22-0.35 dL/g. These new polymers were characterized by FT IR, ¹H NMR, elemental analyses and specific rotation techniques.     

Synthesis and Properties of Novel Fluorinated Poly(amide-imide)s from the 4,4′-Bis(4-trimellitimido-2-trifluoromethylphenoxy)biphenyl and Aromatic Diamines

A novel fluorinated diimide dicarboxylic acid, 4,4′-bis(4-trimellitimido-2-trifluoromethylphenoxy)biphenyl (III), was synthesized from the condensation of 4,4′-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (I) and trimellititc anhydride. A series of soluble poly(amide-imide)s (PAI) V_a–h having inherent viscosities of 0.56–0.97 dL/g were prepared from reacting III with an equivalent amount of diamines by direct polycondensation using triphenyl phosphite and pyridine as condensing agents. The polymer V series afforded tough, transparent, and flexible films. They had tensile strengths ranging from 88 to 112 MPa, elongations at break from 8 to 31%, and initial moduli from 1.9 to 2.7 GPa. The glass-transition temperature (T_g) of the polymers was recorded at 235–300^○C. They had 10% weight loss at a temperature above 502^○C and left more than 54% residue even at 800^○C in nitrogen. In comparison with the nonfluorinated PAI VI series, the fluorinated V exhibited better solubility.     

Synthesis and Structural Characterization of Novel Nanostructured Aromatic Optically Active Poly(Ester–Amide)s Derived from S-tyrosine Containing Symmetric Diol and Aromatic Diacid Chlorides

In this study, at first N,N′-bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)]terephthaldiamide, as a new chiral monomer based on tyrosine amino acid, was synthesized from the reaction of S-tyrosine methyl ester and terephthaloyl dichloride. Then novel nanostructured aromatic optically active and eco-friendly poly(ester–amide)s based on tyrosine amino acid were synthesized by the solution polycondensation of the new diol and a number of aromatic diacid chlorides. The resulting poly(ester–amide)s exhibited good yields, solubility, inherent viscosities, and thermal stability. All polymers were characterized by Fourier transform infrared, ¹H NMR, elemental analysis, and specific rotation. They were also studied by X-ray diffraction, thermogravimetric analysis, and field emission scanning electron microscopy.     

Design and Characterization of Chiral and Thermally Stable Nanostructure Poly(amide-imide)s Containing Different Trimellitylimido-Amino Acid-Based Diacids and 4,4′-Methylenebis(3-chloro-2,6-diethylaniline) Units

In this study new chiral nanostructure poly(amide-imide)s (PAI)s were synthesized via direct polycondensation of different trimellitylimido-amino acid-based diacids and 4,4′-methylenebis(3-chloro-2,6-diethylaniline), using tetra-n-butylammonium bromide and triphenyl phosphite as a green media. The formation of these nanostructure PAIs was confirmed by ¹H-NMR, Fourier transform infrared spectroscopy, specific rotation, elemental analysis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and thermo gravimetric analysis techniques. The FE-SEM micrographs and XRD patterns showed that, the obtained PAIs are nanostructured with different shapes and noncrystalline polymers.     

Morphological and Thermal Properties of Poly(amide-imide)/ZnO Nanocomposites Derived from 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) and 3,5-diamino-N-(4-hydroxyphenyl)benzamide

A new nanostructure poly(amide-imide) (PAI) was prepared from the polymerization of 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid with 3,5-diamino-N-(4-hydroxyphenyl)benzamide using triphenyl phosphite as a condensing agent and tetra-n-butylammonium bromide as a green media. The synthesized polymer was used to prepare PAI/ZnO nanocomposites (PZNC)s using nano-ZnO surface-coupled by N-trimellitylimido-L-alanine diacid as a coupling agent through ultrasonic process. The resulting PZNCs were also characterized by FT-IR, powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TEM and FE-SEM results showed a good dispersion of nanoscale inorganic particles in the polymer matrix.     

Surface Morphology and Properties of Rigid Poly(γ-benzyl L-glutamate) Membrane Modified by Flexible Poly(Vinyl Chloride)

Rigid poly(γ-benzyl L-glutamate)/flexible poly(vinyl chloride) (PBLG/PVC) blend membranes were prepared by casting the polymer blend solution in dichloroethane. Structure and morphologies of the PBLG/PVC blend membranes were investigated by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Thermal, mechanical, and chemical properties of PBLG/PVC blend membranes were studied by differential scanning calorimetry (DSC), tensile tests, and other physical methods. It was found that the introduction of PVC could exert marked effects on the morphology and the properties of PBLG membrane.     

Lipase Catalyzed Synthesis and Thermal Properties of Poly(dimethylsiloxane)–Poly(ethylene glycol) Amphiphilic Block Copolymers

Resin immobilized lipase B from Candida antarctica (CALB) was used to catalyze the condensation polymerization of two difuctional siloxane and poly(ethylene glycol) systems. In the first system, 1,3-bis(3-carboxypropyl)tetramethyldisiloxane was reacted with poly(ethylene glycol) (PEG having a number-average molecular weight, M_n = 400, 1000 and 3400 g mol⁻¹, respectively). In the second system, α,ω-(dihydroxy alkyl) terminated poly(dimethylsiloxane) (HAT-PDMS, M_n = 2500 g mol⁻¹) was reacted with α,ω-(diacid) terminated poly(ethylene glycol) (PEG, M_n = 600 g mol⁻¹). All the reactions were carried out in the bulk (without use of solvent) at 80 °C and under reduced pressure (500 mmHg vacuum gauge). The progress of the polyesterification reactions was monitored by analyzing the samples collected at various time intervals using FTIR and GPC. The thermal properties of the copolymers were characterized by DSC and TGA. In particular, the effect of the chain length of the PEG block on the molar mass build up and on the thermal stability of the copolymers was also studied. The thermal stability of the enzymatically synthesized copolymers was found to increase with increased dimethylsiloxane content in the copolymers.     

New optically active poly(amide-imide)s based on N,N′-(pyromellitoyl)-bis-L-amino acid and 1,3-bis(4-aminophenoxy) propane: Synthesis and characterization

Five new poly(amide-imide)s 8a–e were synthesized through the direct polycondensation reaction of five chiral N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e with 1,3-bis(4-aminophenoxy) propane 7 in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosfite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel poly(amide-imide)s containing trimethylene moiety in the main chain in high yield with inherent viscosities between 0.34 and 0.65 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG). All of the polymers were soluble at room temperature in polar solvents such as N,N-dimethyl acetamide, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e were prepared in quantitative yields by the condensation reaction of pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydide) 1 with L -alanine 2a , L -valine 2b , L -leucine 2c , L -isoleucine 2d , and L -phenyl alanine 2e in acetic acid. Also 1,3-bis(4-aminophenoxy) propane 7 was synthesized by using a two-step reaction. At first 1,3-bis(4-nitrophenoxy) propane 6 was prepared from the reaction of 4-nitrophenol 4 with 1,3-dibromoprapane 5 in NaOH solution. Then, dinitro compound 6 was reduced by using Na₂S. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of new diacid monomers and poly(amide-imide)s: study of structure–property relationship and applications

Two diimide-diacid monomers 4,4′-bis[4″-(trimellitimido)phenyl isopropylidene-4″′-phenoxy]diphenyl sulfone and 4,4′-bis[4″-(trimellitimido)phenylisopropylidene-4″′-phenoxy] were synthesized. The structures of the monomers were characterized by FT-IR and ¹H-NMR spectroscopy. A series of novel poly(amide-imide)s were prepared from this two diacids and aromatic diamines through phosphorylation reaction. The PAIs were characterized by FT-IR, ¹H-NMR, XRD, TGA, and DSC, solution viscosity, solubility test and electrical properties. Poly(amide-imide)s showed excellent solubility due to the presence of flexible groups and isopropylidene unit in the polymer backbone. They also exhibited good thermal stability and the temperatures at which 10% weight loss occurred in the range 385–465 °C. These PAIs found to have a dielectric constant in the range 3.25–4.20 at 10 kHz and have excellent electrical insulation character and can be used as insulation materials for electrical items operating at elevated temperatures.     

Synthesis and Properties of Soluble 3,3′,4,4′-Benzophenonetetracarboxylic Dianhydride Copolyimides Based on 1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenylethane and Commercial Dianhydrides

1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenylethane (BAPPE) is a useful monomer for preparing soluble polyimides, but polyimide synthesized from BAPPE and 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) shows poor solubility. Insoluble BTDA/BAPPE polyimide can copolymerize with soluble polyimides at certain molar ratios (m₂/m₁) to produce arbitrarily soluble copolyimides. To prepare soluble copolyimides, the smallest m₂/m₁ ratio changes due to the matching dianhydrides, depending on the structure of the dianhydride component. When polymers contain the same m₂/m₁ ratio, copolyimides formed through thermal imidization show poorer solubility than these formed through chemical imidization, and copolyimide cyclized at 250°C has a better solubility than that cyclized at 300°C; this is due to the formation of intermolecular linkages during the high-temperature thermal cyclization. Additional, these copolyimides are characterized by good mechanical properties together with good thermal stability, and a comparative study on the properties of the homopolyimide and copolyimide are also presented.     

Synthesis and trans-ureation of N,N’-diphenyl-4,4′-methylenediphenylene biscarbamate with diamines: a non-isocyanate route (NIR) to polyureas

A non-isocyanate route (NIR) of making polyureas of high molecular weight has been found through trans-ureation of N,N’-diphenyl-4,4′-methylenediphenylene biscarbamate (4,4′-DP-MDC) with a variety of diamines and mixed diamines. The preparation of 4,4′-DP-MDC was achieved readily by carbonylation of 4,4′-methylenedianiline (4,4′-MDA) with diphenyl carbonate (DPC) using organic acids as catalysts. It was found that the highest yield (99%) of pure 4,4′-DP-MDC can be isolated in a toluene solution under mild conditions co-catalyzed by benzoic acid and tertiary amine. Trans-ureation of 4,4′-DP-MDC with aliphatic amines indicated that the process is a highly solvent dependent process and was found to be extremely facile in dimethyl sulfoxide (DMSO) at 80 °C and in tetramethylene sulfone (TMS) at 140 °C in absence of any catalyst. Particularly, the most effective polymerization process was developed using tetramethylene sulfone (TMS) as the solvent under reduced pressure for concurrently distilling off phenol from the reaction mixture during the polymerization in a shifting equilibrium towards polyurea. However, this solvent-assisted trans-ureation was found to be in-efficient when N,N’-dimethyl-4,4′-methylenediphenylene biscarbamate (4,4′-DM-MDC) was used in a similar condition for comparison. Thus, an efficient green-chemistry process has been developed based on 4,4′-DP-MDC in making urea prepolymers, urea elastomers and urea plastics all in excellent yields without using reactive methylenediphenylene diisocyanate (MDI) or any catalysts in the trans-ureation polymerizations.     

Effects of N,N′-Ethylenebis(stearamide) on the Properties of Poly(ethylene terephthalate)/Organo-montmorillonite Nanocomposite

Poly(ethylene terephthalate)/organo-montmorillonite (PET/OMMT) nanocomposites were melt-compounded using twin screw extruder followed by injection molding. N,N′-ethylenebis(stearamide) (EBS) was selected as a dispersing agent to improve the dispersibility and exfoliation of OMMT clay in PET matrix. Morphological properties of the PET/OMMT nanocomposites were examined by using X-ray diffraction analysis, transmission electron microscopy and atomic force microscopy. Thermal properties of the nanocomposites were characterized by using dynamic mechanical thermal analysis. It was found that the OMMT are well dispersed and exfoliated in the presence of EBS. Remarkable enhancement in impact strength and storage modulus of PET/OMMT was achieved by the addition of EBS.     

Thermo- and pH-Responsive Polymersomes of Poly(α,β-N-substituted-DL-aspartamide)s

Materials that can respond to multiple stimuli, such as temperature and pH changes, are of considerable interest for applications in drug delivery systems. Notably, α,β-[poly(2-hydroxyethyl)-DL -aspartamide] is a potentially useful material for such applications. This study investigated the temperature and pH responsiveness of polymers structurally similar to α,β-[poly(2-hydroxyethyl)-DL -aspartamide], namely, poly(α,β-N-substituted-DL -aspartamide)s, in aqueous media. These polymers were derived from polysuccinimide (PSI), which was first synthesized via acid-catalyzed bulk polycondensation of L -aspartic acid (L-ASP) in the presence of 85% o-phosphoric acid under N2. Two primary amino alcohols, 4-aminobutanol (4AB) and 6-aminohexanol (6AH), were then respectively utilized to modify PSI to form poly (α,β-N-substituted-DL -aspartamide)s via aminolysis. Different ratios of these two amino alcohols were used to modify the polymer to produce a series of copolymers with lower critical solution temperatures ranging from 53–28°C when dispersed in aqueous media. Moreover, the properties of the poly(α,β-N- substituted-DL -aspartamide)s in aqueous solution were affected by pH changes. The morphology of the particles formed by these amphiphilic polymers was observed using scanning electronic microscopy and transmission electronic microscopy, and the particles were found to be polymersomes with shell and hollow core structures and diameters of 0.5–1 μm. Other properties of this series of self-assembly copolymers were also characterized. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermogravimetric Analysis of Polyesters Derived from 2,2-bis(4-chloroformyl-phenyl)-propane and 4,4′-Biphenyl-Dicarboxyl Chloride

Abstract

The thermal stability and the kinetic parameters of a series of polyesters were studied by non-isothermal thermogravimetry. The thermal decomposition temperatures (TDT) depend principally on the nature of the diphenols, in the sense that when the bulk of the diphenol is increased, the TDT values decrease. The kinetic parameters, determined using the Arrhenius relationship, show that these polyesters degrade by a complex mechanism or possibly two or more superimposed processes, probably due to the complex structure of both diacids and diphenols.     

Synthesis and Thermal Decomposition Studies of Silicon (IV) Compounds with N,N’-Bis(Salicylidene)Ethylenediimine

The silicon (IV) compounds possessing SiN₄O₂ (6), SiN₂O₂C₂ (7, 8), SiN₂O₂CCl (9) and SiN₄O₄ (10) coordinating frameworks have been synthesized in high yield by the reaction of the O,N,N,O- donor salen-type ligand N,N’-bis(salicylidene)ethylenediimine L with different silanes i.e. diethoxydiisocyanatosilane-(C₂H₅O)₂Si(NCO)₂ 1, dichlorodiphenylsilane-Ph₂SiCl₂ 2, dichloromethyl- phenylsilane-MePhSiCl₂ 3, trichlorophenylsilane-PhSiCl₃ 4 and silicon tetrachloride-SiCl₄ 5. The compounds 6–10 have been characterized by elemental analysis, IR, ¹H, ¹³C and ²⁹Si NMR and mass spectrometry. The decomposition reactivity of these compounds has been studied using a Thermal Gravimetric Analyzer (TGA) at a heating rate of 10°C/minute in an inert atmosphere.     

New optically active poly(amide-imide)s from N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)bis-l-phenyl alanine and aromatic diamines: synthesis and characterization

In this work, new optically active poly(amide-imide)s (PAIs) having bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide groups were prepared by the reaction of N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)bis-l-phenyl alanine (4) as a diacid monomer with various readily available aromatic diamines. Triphenyl phosphite (TPP)/pyridine (Py) in the presence of calcium chloride (CaCl₂) and N-methyl-2-pyrrolidone (NMP) were successfully applied for direct polycondensation. The diacid (4) was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (1) with l-phenyl alanine (2) in acetic acid solution. The resulting new polymers were obtained in good yields, inherent viscosities ranging between 0.29 and 0.48 dLg⁻¹ and were characterized with elemental analysis, FT-IR, ¹H-NMR spectroscopy, specific rotation, and thermal gravimetric analysis (TGA, DTG) techniques. Thermogravimetric analysis indicated that the residual weight percent of polymers at 600 °C was between 53.80 and 56.21%, which show these are moderately thermally stable. In addition because of existence of chiral center and optical activity of these polymers, they have potential to be used as chiral stationary phase in chromatography technique for the separation of racemic mixtures.     

Synthesis and characterization of 4,4’–(dimethylsilylene) bis( phenyl chloroformate) and 4,4’–(dimethylgermylene)bis(phenyl chloroformate) and their use in the synthesis of poly(urethanes)

Summary The synthesis of 4,4–(dimethylsilylene)bis(phenyl chloroformate) and 4,4–(dimethylgermylene)bis(phenyl chloroformate) is described according to the same route for the synthesis of bisphenol–A bischloroformate. These compounds were characterized using elemental analysis, FT–IR and NMR spectroscopy. Poly(urethanes) derived from these bischlororformates containing silicon or germane in the main chain, were obtained in benzene solution by reaction with 4,4–methylenedianiline in the presence of pyridine. Poly(urethanes) were characterised by spectroscopic methods and the thermal properties (Tg and thermal stability) were compared with the homologue poly(urethane) obtained from bisphenol–A chloroformate.     

Synthesis of Extraction Resin Containing N,N,N′,N′-Tetraisobutyl Diglycolamide and its Application for Separation of Sr(II) from Rb(I)

Abstract

A novel Levextrel resin containing N,N,N′,N′-tetraisobutyl diglycolamide (TiBDGA) was synthesized by suspension polymerization of styrene and divinylbenzene and its performance for separation of Sr(II) from Rb(I) was investigated. The effects of crosslink degree, stirring speed, and the ratio of porogenic-agents on the resin synthesized were examined. The optimum TiBDGA resin with 40 wt.% divinylbenzene as cross linking agent and 20 wt.% of n-octanol as porogenic-agents provided excellent adsorption capacity of 22.5 mg/g. The distribution coefficient (K _d) of Sr(II) in HNO₃ media onto the resin depended heavily on the acidity in the aqueous solution. The maximum K _d for Sr(II) (7300 mL/g) was observed when the HNO₃ concentration in aqueous phase reached 2 mol/L. The difference in the Sr(II) and Rb(I) distribution coefficients of several orders of magnitude implied that ⁸⁹Sr may be separated from ⁸⁶Rb with a radionuclide purity greater than 99%. And the maximum static adsorption capacity of Sr(II) on the resin was 22.5 mg/g.     

Manufacture and Characterization of Biodegradable Nanocomposites Based on Nanoscale MgAl-Layered Double Hydroxide Modified with N,N′-(Pyromellitoyl)-bis-L-Isoleucine Diacid and Poly(vinyl alcohol)

Bionanocomposite films of poly(vinyl alcohol) (PVA) with Mg-Al LDHs were prepared with different compositions by solution-intercalation method. N,N′-(Pyromellitoyl)-bis-L-isoleucine diacid was synthesized and it was used for organo-modification of chiral MgAl-LDH in distilled water. Hybrid films of PVA and modified chiral LDH were prepared under ultrasonic irradiation technique. The effect of LDH contents on thermal, physicomechanical, and morphological properties of PVA films were investigated by using X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, field emission scanning electron microscopy and transmission electron microscopy techniques. Mechanical data indicated improvement in the tensile strength and modulus with increasing of the LDH loading until 4%.     

Synthesis and characterization of polymers from β-propiolactone and poly(ethylene glycol)s

Uncatalysed polymerizations of β-propiolactone with low-molecular-weight poly(ethylene glycol)s were carried out in bulk, at temperatures in the range of 70 to 120°C. ¹H nuclear magnetic resonance (n.m.r.) and differential scanning calorimetry (d.s.c.) measurements on the resulting products indicated a block copolymer structure. Gel permeation chromatography (g.p.c.) and d.s.c. analyses showed that in some cases the copolymerization is accompanied by homopolymerization of β-propiolactone, probably due to the presence of residual water in the poly(ethylene glycol). N.m.r. and infra-red (i.r.) spectra of copolymers revealed the presence of hydroxyl and carboxyl end groups. The copolymerization reaction may be visualized as a two-step process, in which the ring opening of β-propiolactone takes place on both the hydroxyl groups of poly(ethylene glycol), followed by repetitive monomer addition forming an ester-ether-ester triblock copolymer.