Biodegradable polymers based on renewable resources. V. Synthesis and biodegradation behavior of poly(ester amide)s composed of 1,4:3,6‐dianhydro‐D‐glucitol, α‐amino acid,and aliphatic dicarboxylic acid units

A series of poly(ester amide)s were synthesized by solution polycondensations of various combinations of p‐toluenesulfonic acid salts of O,O′‐bis(α‐aminoacyl)‐1,4:3,6‐dianhydro‐D ‐glucitol and bis(p‐nitrophenyl) esters of aliphatic dicarboxylic acids with the methylene chain lengths of 4–10. The p‐toluenesulfonic acid salts were obtained by the reactions of 1,4:3,6‐dianhydro‐D ‐glucitol with alanine, glycine, and glycylglycine, respectively, in the presence of p‐toluenesulfonic acid. The polycondensations were carried out in N‐methylpyrrolidone at 40°C in the presence of triethylamine, giving poly(ester amide)s having number‐average molecular weights up to 3.8 × 10⁴. Their structures were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. Most of these poly(ester amide)s are amorphous, except those containing sebacic acid and glycine or glycylglycine units, which are semicrystalline. All these poly(ester amide)s are soluble in a variety of polar solvents such as dimethyl sulfoxide, N,N‐dimethylformamide, 2,2,2‐trifluoroethanol, m‐cresol, pyridine, and trifluoroacetic acid. Soil burial degradation tests, BOD measurements in an activated sludge, and enzymatic degradation tests using Porcine pancreas lipase and papain indicated that these poly(ester amide)s are biodegradable, and that their biodegradability markedly depends on the molecular structure. The poly(ester amide)s were, in general, degraded more slowly than the corresponding polyesters having the same aliphatic dicarboxylic acid units, both in composted soil and in an activated sludge. In the enzymatic degradation, some poly(ester amide)s containing dicarboxylic acid components with shorter methylene chain lengths were degraded more readily than the corresponding polyesters with Porcine pancreas lipase, whereas most of the poly(ester amide)s were degraded more rapidly than the corresponding polyesters with papain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2721–2734, 2001     

Synthesis,characterization and properties of a castor oil modified biodegradable poly(ester amide) resin

A biodegradable poly(ester amide) resin was synthesized from N,N-bis(2-hydroxy ethyl) fatty amide of castor oil with maleic anhydride, phthalic anhydride and isophthalic acid (100:30:35:35 mole ratio) by the polycondensation process. The fatty amide of the oil was obtained for the first time with 95% yield. The chemical structure of the synthesized resin was characterized by spectroscopic techniques like FTIR, ¹H NMR and ¹³C NMR. Various physical properties such as acid value, saponification value, iodine value, specific gravity and viscosity of the resin were also determined. Further the rheological behavior, studied in the steady shear mode showed shear thinning behavior of the resin. The epoxy cured poly(ester amide) thermoset using poly(amido amine) hardener exhibited better properties than with the cycloaliphatic amine hardener cured system. TGA studies also revealed higher thermal stability of the former system than the latter. In vitro-biodegradation study of the poly(ester amide) thermoset using Pseudomonas aeruginosa and Bacillus subtilus bacteria revealed superior biodegradability of the thermoset using the former bacterial strain. Excellent chemical resistance against various chemical media including alkali was observed for epoxy-poly(amido amine) cured poly(ester amide) resin over epoxy-cycloaliphatic amine one. The epoxy-poly(amido amine) cured poly(ester amide) thermoset thus has the potential to be used as surface coating material.     

Thermoplastic polyester amides derived from oleic acid

Three lipid-based Polyester Amides (PEAs) with varying ratios of ester and amide linkages were synthesized. Oleic acid was used as the starting material to produce the intermediates, characterized by MS and NMR, used for polymerization. PEAs were characterized by FTIR and GPC. The PEAs were constrained to have similar number average molecular weights, in the 2 × 10⁴ range, thereby enabling comparison of their physical properties from a structural perspective. The thermal behavior of the polymers was assessed by DSC, DMA and TGA. Thermal degradation was not affected by ester/amide ratios, but T_g increased non-linearly with decreasing ester/amide ratios and correlated with hydrogen-bond density and repeating unit chain length. Crystallinity was studied by XRD and DSC. Degree of crystallization and multiple melting behavior as a function of cooling kinetics were explained well by hydrogen-bond density, repeating unit chain length and density of ester moieties. Mechanical properties were investigated by DMA and Tensile Analysis, with a non-linear increase of storage and tensile moduli recorded as a function of decreasing ester/amide ratios. The findings suggest how approaches to the synthesis of lipid-based PEAs can be targeted to the delivery of specific physical properties.     

Structure and high‐resolution thermogravimetry of liquid‐crystalline copoly(p‐oxybenzoate‐ethylene terephthalate‐p‐benzamide)

Thermotropic liquid‐crystalline copoly(ester‐amide)s consisting of three units of p‐oxybenzoate (B), ethylene terephthalate (E) and p‐benzamide (A) were studied by proton nuclear magnetic resonance at 200 and 400 MHz, wide‐angle X‐ray diffraction, and high‐resolution thermogravimetry to ascertain their molecular and supermolecular structures, thermostability and kinetics parameters of thermal decomposition in both nitrogen and air. The assignments of all resonance peaks of [¹H]NMR spectra for the copoly(ester‐amide)s are given and the characteristics of X‐ray equatorial and meridional scans are discussed. Overall activation energy data of the first major decomposition have been evaluated through three calculating techniques. The thermal degradation occurs in three steps in nitrogen and air. The degradation temperatures are higher than 447 °C in nitrogen and 440 °C in air and increase with increasing B‐unit content at a fixed A‐unit content of 5 mol%. The temperatures at the first maximum weight‐loss rate are higher than 455 °C in nitrogen and 445 °C in air and also increase with an increase in B‐unit content. The first maximum weight‐loss rates range between 11.1 and 14.5%min⁻¹ in nitrogen and between 11.9 and 13.5%min⁻¹ in air. The char yields at 500 °C in both nitrogen and air range from 45.8 to 54.3 wt% and increase with increasing B‐unit content. But the char yields at 800 °C in nitrogen and air are quite irregular with the variation of copolymer composition and testing atmosphere. The activation energy and Ln (pre‐exponential factor) for the first major decomposition are usually higher in nitrogen than in air and increase slightly with an increase in B‐unit content at a given A‐unit content of 5 mol%. The activation energy, decomposition order, and Ln (pre‐exponential factor) of the thermal degradation for the copoly(ester‐amide)s in two testing atmospheres, are situated in the ranges of 210–292 kJmol⁻¹, 2.0–2.8, 33–46 min⁻¹, respectively. The three kinetic parameters of the thermal degradation for the aromatic copoly(ester‐amide)s obtained by high‐resolution thermogravimetry at a variable heating rate are almost the same as those by traditional thermogravimetry at constant heating rate, suggesting good applicability of kinetic methods developed for constant heating rate to the variable heating‐rate method. These results indicate that the copoly(ester‐amide)s exhibit high thermostability. The isothermal decomposition kinetics of the copoly(ester‐amide)s at 450 and 420 °C are also discussed and compared with the results obtained based on non‐isothermal high‐resolution thermogravimetry. © 1999 Society of Chemical Industry     

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.     

Proton exchange membranes prepared by simultaneous radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐hexafluoropropylene) films. II. Properties of sulfonated membranes

Proton exchange membranes were prepared by radiation‐induced grafting of styrene onto commercial poly(tetrafluoroethylene‐co‐hexafluoropropylene) films using a simultaneous irradiation technique followed by a sulfonation reaction. The resulting membranes were characterized by measuring their physicochemical properties such as water uptake, ion exchange capacity, hydration number, and proton conductivity as a function of the degree of grafting. The thermal properties (melting and glass transition temperatures) and thermal stability of the membrane were also investigated using differential scanning calorimetry and thermal gravimetric analysis, respectively. Membranes having degrees of grafting of 16% and above showed proton conductivity of the magnitude of 10⁻² Ω⁻¹ cm⁻¹ at room temperature, as well as thermal stability at up to 290°C under an oxygen atmosphere. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2443–2453, 2000     

Chemical modification of crosslinked phenyl acrylate copolymers with monoethanolamine

Copolymerisation of phenyl methacrylate, 4-chlorophenyl acrylate, 4-nitrophenyl acrylate and 2,4,6-tribromophenyl acrylate with divinyl benzene was carried out in aqueous suspension medium at 80°C using benzoyl peroxide as radical initiator. The resulting beaded copolymers were characterised by FTIR. optical and scanning electron microscopy. Polymer analogue reactions of these particulate copolymers with monoethanolamine were carried out at 60.80 and 100°C in dimethyl sulphoxide as solvent. The progress of the reactions was followed by observing the disappearance of phenyl ester carbonyl absorption at 1750 cm⁻¹ and the appearance of 1650cm⁻¹ vibration corresponding to the characteristic amide carbonyl. The percentage conversions were calculated, and the effect of polar substituents in the phenyl acrylates as well as temperature on the reaction are discussed.     

Synthesis of poly(ester‐anhydride)s based on poly(ϵ‐caprolactone) prepolymer

The objective of this study was to prepare high molecular weight poly(ester‐anhydride)s by melt polycondensation. The polymerization procedure consisted of the preparation of carboxylic acid terminated poly(?‐caprolactone) prepolymers that were melt polymerized to poly(?‐caprolactone)s containing anhydride functions along the polymer backbone. Poly(?‐caprolactone) prepolymers were prepared using either 1,4‐butanediol or 4‐(hydroxymethyl)benzoic acid as initiators, yielding hydroxyl‐terminated intermediates that were then converted to carboxylic acid‐terminated prepolymers by reaction with succinic anhydride. Prepolymers were then allowed to react with an excess of acetic anhydride, followed by subsequent polycondensation to resulting high molecular weight poly(ester‐anhydride)s. Upon coupling of prepolymers, size exclusion chromatography analyses showed an increase from 3600 to 70,000 g/mol in number‐average molecular weight (M_n) for the 1,4‐butanediol initiated polymer, and an increase from 7200 to 68,000 g/mol for the 4‐(hydroxymethyl)benzoic acid‐initiated polymer. 4‐Hydroxybenzoic acid and adipic acid were also used as initiators in the preparation of poly(?‐caprolactone) prepolymers. However, with these initiators, the results were not satisfactory. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 176–185, 2001     

Optically active poly(ester‐amide)s: synthesis and characterization

The synthesis and characterization of a new series of chiral poly(ester‐amide)s are reported. They were prepared by the simple reaction of diacid chlorides with biphenolic azo chromophores and optically active dihydroxy compound (isosorbide) in dimethyl acetamide at 100 °C. The polymers containing isosorbide units were optically active. The polymers showed T_g between 100 and 190 °C and were stable up to 400 °C. These poly(ester‐amide)s showed a positive solvatochromism in UV–visible absorption spectra. Second harmonic generation activities were measured by the powder method. © 2001 Society of Chemical Industry     

Synthesis of magnesium hydroxide nanofiller and its use for improving thermal properties of new poly(ether‐amide)

A new poly(ether‐amide; PEA) as a source of polymeric matrix, containing flexible ether group in the main chain was synthesized by direct polycondensation reaction of 1,2‐(4‐carboxy phenoxy)ethane with 4,4‐diaminodiphenyl ether in a medium consisting of N‐methyl‐2‐pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The resulting PEA was characterized by gel permeation chromatography (GPC), ¹H NMR and FT‐IR spectroscopy. Magnesium Hydroxide (MH) nanostructure was synthesized by the reaction of magnesium sulfate and sodium hydroxide by sonochemical method. The MH particle was characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Then Mg(OH)₂ nanostructure was added to poly(ether‐amide) matrix and resulting nanocomposites were characterized by XRD, SEM, and Thermogravimetry Analysis (TGA). Thermal decomposition of the PEA shifted towards higher temperature in the presence of the magnesium hydroxide nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Copolymerization of potassium chloroacetate and potassium N‐chloroacetyl‐6‐aminohexanoate

The polymerization kinetics of potassium chloroacetate (MGL), potassium N‐chloroacetyl‐6‐aminohexanoate (MEA), and their mixtures was studied by Fourier transform infrared spectroscopy. The bulk polycondensation reaction was faster for MEA than for MGL but kinetic differences in the selected temperature range (110–130°C) were not large enough to make unfeasible copolymerization of both monomers. A decrease in the activation energy was deduced for the polycondensation of monomer mixtures with respect to that determined for the homopolymerization reaction of the predominant neat monomer. differential scanning calorimetry data also showed significant differences in the exothermic polycondensation peaks that suggested an effective copolymerization reaction and favored the kinetic process over the corresponding homopolymerization. The resulting new poly(ester amide)s were characterized by spectroscopy and thermal analysis. ¹H NMR spectra of samples with high MEA content revealed the existence of hetero‐sequences whose ratio was slightly lower than that expected for a random polymerization of the two monomers. Samples with high molecular weights were only attained when the MGL molar ratio in the monomer mixture was lower than 65%. Calorimetric data showed that all samples were thermally stable and became amorphous for intermediate compositions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polymer-supported IBX amide for mild and efficient oxidation reactions

A facile simple preparation of polymer-supported IBX amide (IBX amide resin) from chloromethyl polystyrene resin was demonstrated. The IBX amide resins were prepared with high loading levels (∼1.40 mmol g⁻¹). These reagents were found to be mild and efficient oxidants through oxidation of a range of alcohols, sulfides and phosphites to the corresponding carbonyl, sulfoxide and phosphate compounds without over-oxidation at room temperature. Consumed IBX amide resins were reused up to five times without significant loss of oxidative activity after repetitive regeneration.     

Conversion of polyester into heat‐resistant polyamide by reacting with aromatic diamine compound

The ester–amide exchange reaction between poly(ethylene terephthalate) and p‐phenylenediamine in n‐dodecylbenzene as a solvent in the absence of catalyst was carried out to obtain heat‐resistant polyamide. The observation of the amide group generated in the reaction product was made by FTIR analysis and the relative extent of reaction was estimated by the amidation ratio from FTIR and the nitrogen content determined from elemental analysis. The effect of chemical structure in the homologous series of aliphatic and aromatic diamines on the reactivity of ester–amide exchange reaction was studied. How reaction variables such as time, temperature, and the amount of diamine used affected the extent of reaction and the heat‐resistant property of polyamide obtained was thoroughly studied. Finally, a search for an efficient catalyst among metal acetates was attempted. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2502–2512, 2004     

One-pot synthesis of soluble wholly aromatic liquid crystalline copoly(ester amide)s with high thermal and dimensional stability

Abstract

Thermotropic liquid crystalline polymers (LCPs) have been of great interest for electronic packaging. Herein, we introduce a series of wholly aromatic, thermotropic LCPs from copoly(ester amide)s of 6-hydroxy-2-naphthalic acid, isophthalic acid, terephthalic acid, and 4-aminophenol, prepared by a convenient one-pot melt polycondensation. Almost synthesized copoly(ester amide)s exhibited good solubility in common organic solvents at room temperature. Furthermore, they possessed high thermal stability with 2% degradation temperatures (T_id) of 359–368?°C and the char yields (at 600?°C) of 50.3–55.6%. The synthesized copoly(ester amide)s had relatively low coefficient of thermal expansion (CTE) values, which were 35.85–41.21?ppm °C^?1 in the temperature range of 50–200?°C. Furthermore, an annealing process could be employed to improve the thermomechanical properties of synthesized polymers. For instance, the CTE of sample LCP3 in range temperature of 275–315?°C was reduced by more than 90% after annealing at 320?°C for 1?h, implying the feasibility for electronic packaging.     

Synthesis of poly(amide‐ester)s by microwave methods

The polycondensation of sebacic acids and ω‐amino alcohols by microwave irradiation was studied. The results were compared to those obtained from conventional melt polycondensation of poly(amide‐ester)s. It was found that the reaction proceeded at a much higher rate upon microwave irradiation. A high yield of thermally stable poly(amide‐ester)s was obtained. The microwave‐synthesized compounds were fully characterized by FTIR and ¹H‐NMR spectroscopy, gel permeation chromatography, and a solubility test. The thermal properties of the poly(amide‐ester)s also were investigated. The results showed that the chemical‐physical properties of the polymers were in good agreement with those of polymers obtained by conventional synthesis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1952–1958, 2007     

Chelation of chitosan derivatives with zinc ions. II. Association complexes of Zn2+ onto O,N‐carboxymethyl chitosan

The chelation of zinc ions onto O,N‐carboxymethyl chitosan (ONCMCh) was characterized using a Fourier transform infrared (FTIR) spectrophotometer and a scanning electron microscope (SEM). From the FTIR spectra, little change in the absorption intensities and frequencies at 3300–3600 cm⁻¹ of Zn²⁺ ONCMCh chelated specimens suggested that  OH and  NH₂ groups were not participating in the chelation reaction. The absence of absorption bands at 1755–1700 cm⁻¹ suggested that the carboxyl group CO was not ionized, and the ionized CO bands were observed at 1400–1600 cm⁻¹ for chelated specimens. Thus, the chelation sites took place at the carboxyl group rather than at the  OH and NH₂ groups. It also confirmed that water‐insoluble chelates, which were formed through the Zn O and Zn N bonds, presented a tetrahedral structure. The water‐soluble complexes where zinc ions connected with oxygen of CO and water molecules were only due to electron attraction. Formation of different microstructures on the surfaces, as revealed by SEM, provided evidence to distinguish different chelating mechanisms between water‐soluble and water‐insoluble complexes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1476–1485, 2001     

Quaternized poly (2,6-dimethyl-1,4-phenylene oxide) crosslinked by tertiary amine and siloxane for anion exchange membranes

A series of tertiary amine and siloxane crosslinked composite anion exchange membranes were prepared by incorporating 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane (EHTMS) and N,N,N′,N′-Tetramethyl-1,6-hexanediamine (TMHDA) into N-Methyldiethanolamine (MDEA)-functionalized poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) backbone via sol-gel process. The resultant membranes named as AEM-X (X = 1, 2, 3, 4), which own a three-dimensional (3D) cross-linking structure, exhibit superior swelling resistance, mechanical properties, even the thermal stability is up to 220°C. Compared with AEM-1 (contains no crosslinker), the swelling ratio of AEM-2 obviously decreases by 10.2% at 80°C, while the OH⁻ conductivity of AEM-2 has a merely 1.9% decline (20.6 mS cm⁻¹) at 80°C and can maintain 67% of its initial value in a 2 M aqueous NaOH at 80°C for 240 h. The simultaneous introduction of inorganic siloxane and organic linear crosslinker provides a new idea for the preparation of anion exchange membranes with largely improvement in dimensional stability and alkali resistance while the ionic conductivity is kept at comparatively high level.     

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     

Photopolymerizaton of hyperbranched aliphatic acrylated poly(amide ester). II. Photopolymerization kinetics

A hyperbranched aliphatic poly(amide ester) ending with hydroxyl groups based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid (DKBA) and 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol (TMP) was modified with acryloyl chloride, resulting in a radiation‐curable, hyperbranched acrylated poly(amide ester). This hyperbranched polymer was characterized with respect to ultraviolet cure rate, unsaturation conversion, and mechanical properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1637–1641, 2001     

Miscible blends of conductive polyaniline with tertiary amide polymers

Polyaniline (PANI) was doped with p-phenolsulfonic acid (PSA) or 5-sulfosalicylic acid (SSA). The PANI salts were blended with poly(N-vinyl-2-pyrrolidone), poly(N-methyl-N-vinylacetamide), poly(N,N-dimethylacrylamide), or poly(2-methyl-2-oxazoline) by solution casting from dimethyl sulfoxide. Blends containing up to 50% by weight of PANI salt were homogeneous and each exhibited a single glass transition temperature, indicating miscibility. Fourier transform infrared spectroscopic studies indicated that the carbonyl groups of the tertiary amide polymers interacted with the PANI salt as evidenced by the development of a shoulder at a lower frequency in the carbonyl stretching band. Electrical conductivities of the blends are in the range 10⁻⁵ to 10⁻³ S/cm, depending on the blend composition. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1839–1844, 1998