Novel poly(amide‐hydrazide)s and copoly(amide‐hydrazide)s from bis‐(4‐aminobenzyl) hydrazide and aromatic diacid chlorides: Synthesis and characterization

A new aromatic diamine, viz., bis‐(4‐aminobenzyl) hydrazide (BABH), which contains preformed hydrazide and methylene linkage, was synthesized starting from α‐tolunitrile. The BABH and intermediates involved in its synthesis were characterized by spectroscopic methods. Novel poly(amide‐hydrazide)s were synthesized by low temperature solution polycondensation of BABH with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). Furthermore, two series of copoly(amide‐hydrazide)s, based on different mol % of BABH and bis‐(4‐aminophenyl) ether (ODA) with IPC/TPC were also synthesized. Poly(amide‐hydrazide)s and copoly(amide‐hydrazide)s were characterized by inherent viscosity [η_inh], FTIR, solubility, X‐ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The polycondensation proceeded smoothly and afforded the polymers with inherent viscosities in the range of 0.18–0.93 dL/g in (NMP + 4% LiCl) at 30°C ± 0.1°C. These polymers dissolved in DMAc, NMP or DMSO containing LiCl. The solubility of copolymers was considerably improved in line with less crystalline nature due to random placement of constituent monomers during the copolymerization. XRD data indicated that poly(amide‐hydrazide)s from BABH alone and IPC/TPC had higher crystallinity than the corresponding copoly(amide‐hydrazide)s derived from a mixture of BABH and bis‐(4‐aminophenyl) ether (ODA). Polymers showed initial weight loss around 160°C which is attributed to the cyclodehydration leading to the formation of corresponding poly(amide‐oxadiazole)s. Copolyamide‐hydrazides showed T_max between 400 and 540°C which is essentially the decomposition of poly(amide‐oxadiazole)s. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of fluorinated poly(imide–amide–sulfone)s

A series of new, fluorinated poly(imide–amide–sulfone)s has been synthesized by solution polycondensation of aromatic diamines containing sulfone groups with diacid chlorides incorporating both imide and hexafluoroisopropylidene units. These polymers are soluble in polar amidic solvents, and their solutions can be cast into colorless, thin, flexible films having good electrical insulating properties and high thermal stability. The dielectric constant value is 3.49–3.68. The decomposition temperature in air is 464–479°C, and the glass transition temperature is in the range 279–359°C. All these characteristics have been discussed and compared with those of related fluorinated poly(imide–amide)s which do not contain sulfone groups and with other imide polymers without hexafluoroisopropylidene units. © 1995 John Wiley & Sons, Inc.     

Poly(amide‐ester)s derived from dicarboxylic acid and aminoalcohol

A series of alternating aliphatic poly(amide‐ester)s, derived from dicarboxylic acid and aminoalcohols, were obtained by polycondensation in melt. All poly(amide‐ester)s were characterized by FTIR and ¹H/¹³C‐NMR spectroscopies. The synthesized polymers showed an inherent viscosity ranging from 0.4 to 1.0 dL g^?1. Thermal analysis showed melting points within the range 100–115°C and glass transition within the range 30–60°C. Decomposition temperatures were more than 200°C higher than the corresponding melting temperatures. The polymers can thus be processed from the melt. The processed polymers were partially crystalline with good thermal stability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 362–368, 2005     

Synthesis and characterization of fluoropoly(amide–sulfonamide)s via polycondensation

Novel fluorine-containing polymers, fluoropoly(amide–sulfonamide)s were synthesized for the first time by polycondensation from β-hydroxytetrafluoroethanesulfonic acid sultone (TFE-sultone) and hexamethylenediamine. The chemical structures of the obtained F-PASAs were characterized by intrinsic viscosity measurements, GPC, FTIR, ¹H NMR, ¹⁹F NMR and element analysis in detail. Thermal properties and optical property of F-PASAs were investigated by DSC, DMA, TGA and UV–vis spectra, respectively. The investigation indicated that these functional fluoropolymers in which there are both amide and sulfonamide linkages along the polymer main chains possessed distinctive structure as well as unique properties such as thermal properties, clean and high transparency and compatibility with nylons.     

Synthesis and characterization of silicon‐containing poly(amide‐amide)s

A modified new aromatic diacid, bis[(4‐carboxyphenyl) 4‐benzamide] dimethylsilane (IV) with preformed amide linkages and a silicon moiety was synthesized and characterized by IR, NMR, mass spectroscopy, and a physical constant. Novel poly(amide‐amide)s were synthesized from IV and aromatic diamines by Yamazaki's direct polyamidation method in N‐methyl pyrrolidinone. The polymers were obtained in excellent yields and showed reduced viscosities in the range of 0.42–6.15 dL/g. They were readily soluble in aprotic polar solvents. These poly(amide‐amide)s showed glass‐transition temperatures of 303–378°C as measured by DSC and showed no weight loss below 377°C in a nitrogen atmosphere. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1610–1617, 2001     

Poly(styrene–maleic anhydride) functionalized graphene oxide

In this study, poly(styrene–maleic anhydride) functionalized graphene oxide (SMAFG) was fabricated with in situ polymerization. The sample was characterized with Raman spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and ultraviolet–visible absorption. The results of the experiments show that the thermal stability of SMAFG was improved significantly, and it also possessed a good dispersion in N,N‐dimethylformamide, N,N‐dimethylacetamide, aniline, and certain organic solvents. The calculated Hildebrand parameter of SMAFG was 23.8 MPa^1/2. This new method will broaden the applications of graphene, and the experiment showed that it could effectively improve the strength of polyamide 6 (PA6) compared with the pure PA6 fiber. The tensile strength of the SMAFG/PA6 composite fiber improved 29%, and the Young's modulus improved 33%, so this kind of functionalized graphene oxide can be used in the preparation of polymeric composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41987.     

Synthesis and characterization of new biodegradable fluorescing poly(amide‐anhydrides)

Biodegradable/alternate/poly(amide‐anhydrides), [? C(O)PhNHC(O)(CH₂) _nC(O)O? ] _x, were synthesized by melt polycondensation, where n was 2, 3 or 4. The polymers have been characterized by NMR, DSC, wide‐angle X‐ray diffractometry and fluorometry. All the polymers are amorphous and their T_g ranges from 60 to 80 °C. Poly(p‐(carboxyethylformamido)benzoic anhydride) (PCEFB) as a film or in solution in chloroform can emit strong fluorescence, which was not observed for the other two polyanhydrides (n = 3, 4). The maximum emission wavelength varies with the excitation wavelength, 480 and 520 nm at the excitation wavelength of 470 nm, and 430 nm at 356 nm. In addition, the fluorescence intensities increase linearly with the molecular weight of PCEFB. Such inherent fluorescing properties of PCEFB, together with its biodegradability, make the polymer a potential visible matrix for drug delivery. © 2001 Society of Chemical Industry     

Poly(methyl methacrylate)–epoxy vitrimer composites

In this study, we synthesized poly(methyl methacrylate) (PMMA) epoxy vitrimer composites by doping methyl methacrylate (MMA) and benzoyl peroxide into a curing system of epoxy resin and citric acid. The vitrimer composites were characterized with dynamic mechanical thermal analysis, scanning electron microscopy, and stress‐relaxation and lap‐shear testing. The test results show that with increasing amount of MMA, the existence of PMMA in the epoxy vitrimer matrix in the form of intermiscible, slightly soluble, and phase separation became more evident. When the doping amount of PMMA reached 10–25 wt %, the bonding strength of the PMMA–epoxy vitrimer composites was about two times that of the epoxy vitrimer (from 2.3 to 4.3 MPa). This showed that the self‐healing strength of the vitrimer composites was better than that of the pure vitrimer. When the PMMA in the epoxy matrix was in a slightly soluble form, the linear PMMA improved the mechanical properties of the epoxy vitrimer by physical winding. At the same time, the doping of PMMA promoted the transesterification rate of the epoxy vitrimer and enhanced the bonding strength of the composites without lowering the epoxy vitrimer glass‐transition temperature. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46307.     

Isocyanate‐ and Solvent‐Free Route to Thermoplastic Poly(amide‐urea) Derived from Renewable Resources

This study reports on tailoring biobased aliphatic poly(amide‐urea) (PAU) thermoplastics by means of reactive extrusion requiring neither the use of diisocyanate monomers nor time‐consuming PAU polycondensation in a separate step prior to melt processing. Key intermediate is N ,N′‐carbonyl‐biscaprolactam (CBC), which enables rapid and temperature‐programmable polycondensation of biobased diamines and difunctional aminoamides (AA) derived from diamines and dicarboxylic acids. Within a few minutes during melt processing using a twin‐screw extruder, CBC‐mediated advancement of biobased diaminoamides affords high molecular weight PAU. Whereas PAUs derived from short‐chain AAs are stiff and brittle materials with high melting temperatures close to thermal decomposition; the incorporation of AAs derived from sebacic acid and dimer fatty acid renders urea‐functional thermoplastics flexible and processable. Hence, the variation of oligomethylene segment lengths by incorporating short‐ and long‐chain AA building blocks in CBC‐mediated melt‐phase polycondensation governs PAU melting temperature (124–249 °C), Young's modulus (100–1900 MPa), tensile strength (6–51 MPa), and elongation at break (0.3–230%).

     

Poly(amide‐imides): Wire Enamels with Excellent Thermal and Chemical Properties

Poly(amide‐imide) resins are versatile high‐performance polymers used as primary electrical insulation. They can be synthesized by three well‐established methods, of which only two are commercially exploited. Outstanding characteristics include high thermal performance, chemical and abrasion resistance, and low coefficient of friction. Other industries also rely on these same properties for use as coatings, extrusion resins and films. Recent developments are discussed and future trends/product offerings are reviewed. Developments include corona‐resistant enamels, self‐lubricated and high‐abrasion‐resistance coatings. The hybrid automobile industry offers opportunities for further innovations in primary electrical coatings.

     

Poly(vinyl alcohol)–lignin blended resin for cellulose‐based composites

Wood has limitations in strength because of its biostructural defects, including vessels. To overcome this limitation, composite materials can be innovated by breaking wood down into cellulose and lignin and reassembling them for bio‐originating strong structural materials. In this study, an ecofriendly resin was developed that was suitable for cellulose‐based composites. To overcome the low dimensional stability of lignin and to increase its interactions with cellulose, it was blended with poly(vinyl alcohol) (PVA). The PVA–lignin resin was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, thermal analysis, mechanical tensile testing, and lap‐shear joint testing. The adhesion properties of the PVA–lignin resin increased with increasing PVA content. PVA played the role of synthetic polymer and that of linker between the cellulose and lignin, like hemicellulose does in wood. The PVA–lignin resin exhibited a high miscibility, mechanical toughness, and good adhesion properties for nanocellulose composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46655.     

Synthesis and characterization of novel optically active poly(amide‐imide)s

4,4′‐(Hexafluoroisopropylidene)‐bis‐(phthalic anhydride) (1) was reacted with L ‐leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine and the resulting imide‐acid (4) was obtained in quantitative yield. The compound (4) was converted to the diacid chloride (5) by reaction with thionyl chloride. The polymerization reaction of the imide‐acid chloride (5) with 1,6‐hexamethylenediamine (6a) , benzidine (6b) , 4,4′‐diaminodiphenylmethane (6c) , 1,5‐diaminoanthraquinone (6d) , 4,4′‐sulfonyldianiline (6e) , 3,3′‐diaminobenzophenone (6f) , p‐phenylenediamine (6g) and 2,6‐diaminopyridine (6h) was carried out in chloroform/DMAc solution. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by IR, elemental analyses and specific rotation. Some structural characterization and physical properties of those optically active poly(amide‐imide)s are reported. © 1999 Society of Chemical Industry     

Preparation and characterization of graphene‐agar and graphene oxide‐agar composites

Biodegradable counterparts of petro plastics for packaging applications are highly desired due to environmental considerations. Agar can be a potential material due to its availability and biodegradability. However, moderate mechanical strength and thermal stability, in addition to poor resistance against water, needs to be addressed before agar can be commercially implemented as packaging material. As a step toward this objective, graphene oxide (GO) and reduced GO (RGO) were incorporated in agar and were solution casted in the form of films. The tensile strength was increased by 118.4% and 69.4% at 2% GO and 2% RGO loading, respectively. Higher interfacial bonding between GO and agar compared to that of RGO and agar was attributed for the observed mechanical properties. Resistance to swelling and hydrophobicity (contact angle) of the composite were improved as well when compared to pure agar. The tensile strength and the contact angle values were however, decreased after the addition of 2% GO and 2% RGO. The morphological investigation showed that the formation of pores at higher concentration of reinforcement was the contributing factor for the decrease in tensile strength. No significant change in thermal properties was observed. The transmittance value was reduced to 0% after the incorporation of GO and RGO. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45085.     

Synthesis and characterization of new aromatic poly(amide–imide)s based on 4‐aryl‐2,6‐bis(4‐trimellitimidophenyl) pyridines

New diimide–dicarboxylic acids, ie 4‐phenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis‐(4‐trimellitimidophenyl)pyridine, were synthesized by the condensation reaction of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis(4‐aminophenyl)pyridine with trimellitic anhydride in glacial acetic acid or dimethylformamide. The monomers were fully characterized by FT‐IR and NMR spectroscopies, and elemental analyses. A series of novel poly(amide–imide)s with inherent viscosities of 0.68–0.87 dl g^?1 was prepared from the two diimide–diacids with various aromatic diamines by direct polycondensation. The poly(amide–imide)s were characterized by FT‐IR and NMR spectroscopies. The λ_max data for the resulting poly(amide–imide)s were in the range of 260–292 nm. These polymers exhibited good solubilities in polar aprotic solvents. The 10 % weight loss temperatures are above 485 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of new rigid‐rod and organosoluble poly(amide–imide)s based on 1,4‐bis(trimellitimido)‐2,3,5,6‐tetramethylbenzene

A series of new aromatic poly(amide–imide)s (PAIs) was synthesized by triphenyl phosphite‐activated polycondensation of the diimide–diacid, 1,4‐bis(trimellitimido)‐2,3,5,6‐tetramethylbenzene (I), with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), pyridine, and calcium chloride. The PAIs had inherent viscosities of 0.82–2.43 dL/g. The diimide–diacid monomer (I) was prepared from 2,3,5,6‐tetramethyl‐p‐phenylenediamine with trimellitic anhydride (TMA). Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP, N,N‐dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF). Transparent, flexible, and tough films of these polymers could be cast from DMAc solutions. Their cast films had tensile strengths ranging from 80 to 95 MPa, elongation at break from 10 to 45%, and initial modulus from 2.01 to 2.50 GPa. The 10% weight loss temperatures of these polymers were above 510°C in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1162–1170, 2000     

Poly(styrene‐alt‐maleic acid)–metal complexes with divalent metal ions. synthesis,characterization, and physical properties

Polymer–metal complexes of the alternating copolymer styrene and maleic acid with Cu(II), Co(II), Ni(II), and Zn(II) were synthesized and characterized by elemental analysis, infrarred and electronic spectra, and thermogravimetry. In addition, magnetic measurements were performed and the electrical conductivity was studied at different temperatures. Semiempirical calculations at the PM 3 level were carried out to elucidate the geometrical arrangement of the polychelates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1310–1315, 2001     

Poly(methyl acrylate)/Na‐montmorillonite intercalated composites: Preparation and characterization

Poly(methyl acrylate)/Na‐montmorillonite intercalated composites were prepared by free‐radical polymerization using benzoyl peroxide as a radical initiator in an aqueous medium. XRD patterns confirmed that the increase in interlayer spacing of Na‐montmorillonite (Na‐MMT) from 1.21 to 1.64 nm supports the intercalation. Although the width of the intercalated, delaminated montmorillonite aggregates are less than 100 nm (as seen in transmission electron microscopy), the prepared samples are members of the intercalated composite group. The samples exhibited better thermal stability than the pure polymer. Nitrogen adsorption capacity decreased due to the hindering of molecule diffusion and shielding of the intercalated aggregates by the polymer matrix. The decrease in moisture and water uptake of the samples indicated that the hydrophilic nature of montmorillonite changed greatly due to the hydrophobicity with increasing polymer content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of new poly(amide–imide)s derived from trimellitylimido‐L‐phenylalanine

N‐Trimellitylimido‐L ‐phenylalanine was prepared from the reaction of 1,2,4‐benzenetricarboxylic anhydride with L ‐phenylalanine in N,N‐dimethylformamide solution at refluxing temperature. The direct polycondensation reaction of the monomer imide‐diacid with 4,4′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylmethane, 1,4‐phenylenediamine, 1,3‐phenylenediamine, 2,4‐diaminotoluene, 4,4′‐diaminodiphenylether and benzidine was carried out in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrrolidone, pyridine and calcium chloride. The resulting poly(amide–imide)s, PAIs, having inherent viscosities of 0.21–0.45 dlg^?1 were obtained in high yield. All of the above compounds were fully characterized by IR spectroscopy and elemental analyses. The optical rotation of all PAIs has also been measured. Some structural characterization and physical properties of these new optically active PAIs are reported. © 2001 Society of Chemical Industry     

Flexible freestanding cotton–graphene composites for lithium‐ion batteries

Flexible freestanding cotton–graphene (CGN) composites were prepared by a simple immersion and freeze‐drying method and a thermal annealing process together. The composites had a constant cotton microstructure covered by graphene. The microstructure and morphology of the composites could be easily adjusted through the variation of the thermal annealing temperatures. Electrochemical tests demonstrated that the annealing temperatures had great effects on the electrochemical performances of the obtained composites. The CGN composite annealed at 700 °C exhibited a reversible capacity of 245.2 mAh/g after 100 cycles. Even after it was bent 1000 times, the CGN composite still maintained its superior electrochemical properties. The results suggest that because of its high flexibility and excellent conductive and electrochemical activities, the CGN composites could be used as lithium‐ion battery anode materials on a large scale for corresponding applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44727.     

Star poly(2‐ethyl‐2‐oxazoline)s—synthesis and thermosensitivity

A series of star‐shaped poly(2‐ethyl‐2‐oxazoline)s was prepared by cationic polymerization. The polymerization was initiated by dipentaerythrityl hexakis(4‐nitrobenzene sulfonate) and a tosylated hyperbranched polymer of glycidol. The polymerization proceeded in a controlled manner. The star structure of the products was determined by nuclear magnetic resonance. The molar mass distributions that were measured by gel permeation chromatography with multiangle laser light scattering were narrow, and the experimental values of the molar masses were close to those predicted. The very compact structure of the polymers obtained (compared with the linear counterparts) confirmed the star formation. The star poly(2‐ethyl‐2‐oxazoline)s show a phase transition temperature in the range 62–75 °C. Comparison of this phase transition temperature with that of the linear poly(2‐ethyl‐2‐oxazoline)s with the same molar masses indicates the influence of molar mass and topological structure of the macromolecule on temperature behavior. The prepared copolymers are spherical, which might be useful for the controlled transport and release of active compounds. Copyright © 2011 Society of Chemical Industry