Synthesis of polyesteramides: poly(ethylene adipate amide) and poly(ethylene succinate amide) and their application as corrosion inhibitors in paint formulations

Aliphatic polyesters based on adipic or succinic acid were synthesized by polycondensation reaction to produce poly(ethylene adipate) (PEA) and poly(ethylene succinate) (PES), respectively. The prepared polyesters (PEA and PES) were modified with monoethanol amine to produce polyesteramides, namely polyethylene adipate amide (PEAA) and polyethylene succinate amide (PESA). Full characterization of PEA, PES, PEAA and PESA was achieved using thermal, spectroscopic, and gel permeation chromatography analyses. The prepared aliphatic polyesters (PEA and PES) and polyesteramides (PEAA and PESA) were evaluated as corrosion inhibitors in paint formulations. Two groups of paints were prepared with 24 paint formulations based on medium oil alkyd resin, talc, titanium dioxide, drier and the prepared polymers with different types and concentrations. All the formulations are free from any inorganic anticorrosive pigments. PEA and PEAA were incorporated in Group I formulations. Paint formulations that contain PEA are six formulations F1A, F2A, F3A, F4A, F5A and F6A in addition to F1Aa, F2Aa, F3Aa, F4Aa, F5Aa and F6Aa based on PEAA with different concentrations 0.5%, 1.5%, 2.5%, 3.5%,4.5% and 5.5%, respectively. Group II formulations contain twelve other prepared formulations F1S, F2S, F3S, F4S, F5S and F6S based on PES, in addition to F1Sa, F2Sa, F3Sa, F4Sa, F5Sa and F6Sa based on PESA with the same series of concentrations. Physical, mechanical, and chemical properties of the coated films were determined. Corrosion tests in addition to surface analysis by a scanning electron microscope were performed to study the protection efficiency of such coats on steel. It was found that the synthesized polyesteramides can protect steel from corrosion successfully in 3.5% NaCl solution depending on their adsorption on the steel surface. The extent of steel protection coated with PESA formulations was slightly higher than PEAA.     

Influence of the metal centers of 2,6‐bis(imino)pyridyl transition metal complexes on ethylene polymerization/ oligomerization catalytic activities

Much work on bis(imino)pyridyl complexes with Fe(II) and Co(II) as ethylene polymerization catalysts has been reported in terms of designing new analogous ligands, while little work has been dedicated to the study of the effect of the metal center on catalyst performance. A series of bis(imino)pyridyl‐MCl₂ (M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II)) transition metal complexes were synthesized, for which single crystals of the Co(II) and Cu(II) complexes were obtained. The crystal structures indicated that these complexes had similar coordination geometries. Being applied to ethylene polymerization at 25 °C and employing 500 equiv. of methylaluminoxane as co‐catalyst, the complexes with Fe(II), Co(II) and Ni(II) centers showed, respectively, catalytic activities of 1.25 × 10⁶ g (mol Fe)^?1 h^?1 Pa for ethylene polymerization, and 3.98 × 10⁵ g (mol Co)^?1 h^?1 Pa and 5.13 × 10³ g (mol Ni)^?1 h^?1 Pa for ethylene oligomerization. In contrast, the complexes with Cu(II) and Zn(II) centers were inactive. Crystal structure data showed that the coordination interactions provided a comparatively reliable quantification of the selectivity of the bis(imino)pyridyl ligand for the studied metal ions, which was in reasonable agreement with the Irving–Williams list. Moreover, for the Ni(II) and Cu(II) complexes, the strong coordination bonds and small N(imino)? M? N(imino) angles were unfavorable for several steps in the mechanism, such as ethylene coordination to the metal center, ethylene migratory insertion and olefin chain growth. All of these will reduce the speed of the overall reaction, indicating a decrease of catalytic efficiency in a given period. The poor activity of the Zn(II) complex for ethylene polymerization may be related to the reduction process by the alkylating agent. Copyright © 2010 Society of Chemical Industry     

PET/PEA共混物的非等温结晶及晶态结构

采用升、降温DSC和广角X射线衍射等测试手段研究了不同共混比的PET/液晶共聚酯酰胺(PEA)机械共混物、溶液共混物的非等混结晶和晶态结构。结果表明PEA在20％的范围内能起到成核剂的作用,促进PET结晶,并且当PEA的加入量为2.5％时,PET最易结晶;共混物中PET的晶态结构受PEA的影响不大,PEA的引入使共混物各晶面间距增大,共混物的结晶度呈现先上升而后降低之趋势。     

Degradable poly(ester amine) based on poly(ethylene glycol) dimethacrylate and polyethylenimine as a gene carrier

Degradable poly(ester amine) (PEA) based on poly(ethylene glycol) dimethacrylate (PMEG) and polyethylenimine (PEI) were synthesized by Michael addition reaction. The ratios of PEI to PMEG in PEAs were 0.99, 1.02, and 1.07 with corresponding number‐average molecular weight of 1.3 × 10⁴, 1.2 × 10⁴, and 0.9 × 10⁴, respectively. Degradation rate of PEA at pH 7.4 was higher than that at pH 5.6. Good plasmid condensation and protection ability was shown when N/P molar ratio of PEA to DNA was above 15 (N: nitrogen element in PEA, P: phosphate in DNA). PEA/DNA complexes had positive zeta potential, narrow size distribution, good dispersity, and spheric shape with size below 250 nm when N/P ratio was above 30, suggestion of their endocytosis potential. Compared with PEI 25 KDa, the PEAs showed essential nontoxic to HeLa, HepG2 and 293T cells. With an increase in the molecular weight of PMEG, the transfection efficiency of PEAs in HeLa, HepG2 and 293T showed a tendency to decrease as well as the percent decrease of gene transfection efficiency with serum. The mechanism of PEA‐mediated gene transfection was attributed to “proton sponge effect” of PEI in the PEA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Syntheses and properties of the PET‐co‐PEA copolyester

An aliphatic‐aromatic random‐block copolyester of poly(ethylene terephthalate) (PET), and poly(enthylene adipate) (PEA), PET‐co‐PEA, was synthesized via melt polycondensation. The chemical structure of the products were characterized by two kinds of spectroscopic techniques (Fourier transform infrared and ¹H‐NMR). The thermal properties of the copolyester were characterized by thermogravimetry analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. It was found that the crystallization ability, melting point, glass transition temperature of the random‐block coplyester decreased apparently. Meanwhile, the tensile strength and hydrolysis performance were measured as well. The result showed that the random‐block copolyesters PET‐co‐PEA displayed excellent properties in elasticity and strength. In addition, the potential degradability was found in hydrolysis measurement. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44967.     

Epitaxial nucleation,modulated structure of molecular aggregation,and enhanced thermal degradation temperature of poly(ethylene adipate): Effects of the naturally occurring uracil as a nucleator

We fabricated a novel bio-composite using the poly(ethylene adipate) (PEA) and naturally occurring uracil (URA), in which the URA with the full biocompatibility and degradability acted as a nucleator (NA). A distinct enhancement was found in the crystallizability, melt-crystallization temperature (T_c), and crystallization rate of the PEA upon incorporation of the URA, an indicative of a good NA of the URA. The underlying nucleation mechanism of the PEA is the epitaxial nucleation, attributed to the extremely good matching between the crystal lattice of the PEA and URA. The H-bond interaction exists between the carbonyl/ester segment of the PEA crystalline phase and URA. With loading of the URA, both the carbonyl and ester fell behind the CH₂ in the segmental reorganization in the crystallization process of the PEA. The PEA/1%URA showed an enhancement in the T_d in the TG measurement (i.e. increased stability in thermal degradation), mainly attributed to the flame retardance effect of the URA.     

Electron microscopic observations of inclusion complexes of α-, β-, and γ-cyclodextrins

Inclusion complexes of α-, β-, and γ-cyclodextrins (α-, β-, and γ-CyDs) were prepared with poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and poly(ethylene adipate) (PEA), respectively. By observing respective inclusion complexes by transmission electron microscopy, it was found that the crystalline complexes grew as follows: (1) α-CyD-PEO complexes formed a hexagonal crystal, (2) β-CyD-PPO complexes crystallized with hexagonal lateral packing of molecular columns with their axes tilted at the basal plane, and (3) γ-CyD-PEA crystallized in a tetragonal form with a super lattice with cell dimensions a=b=13.40 nm, which consisted of sub-cell with cell dimensions a′=b′=1.657 nm. No diffuse scattering was observed in the electron diffraction pattern of complexes of α-CyD-PEO and β-CyD-PPO, because disordering of guest molecules within host channels gave no diffuse scattering as long as host molecules were arrayed in an ordered way. γ-CyD-PEA complexes gave characteristic streaky diffuse scattering along a^* and b^*. Stacking faults occurred in γ-CyD-PEA complexes.     

Chelating polymer-based membranes. Preparation and use for metal ion scavenging and sorption of murine immunoglobulin G by immobilized Ni(II) ions

Copolymers of 2-(2-hydroxyethoxy)ethyl methacrylate and ethylene dimethacrylate in the form of homogeneous membrane sheets were modified by chelating groups of iminodiacetic acid (IDA) in a two step reaction. The obtained sorbents showed high chelating capacity for Ni(II), Cu(II) and Fe(III) ions (up to 1.3 mmol/g). The potential use of immobilized Ni(II)-IDA complexes for sorption of murine immunoglobulin G by the immobilized metal affinity (IMA) method was tested. The sorption behaviour was characterized by a Langmuir-Freundlich adsorption isotherm. It was shown that the chelating membranes could be used for the sorption of low amounts of protein.     

Thermal and mechanical properties of poly(esterurethane) modified by copolyamide segments of various molecular weight

Thermoplastic polyurethane elastomers (TPUs) from diol-terminated poly(ethylene adipate) (PEA), 1,4-butanediol (BD) and 4,4′-diphenylmethane-diisocyanate (MDI) were modified by copolymerizing with diamine-terminated nylon-6/6,6 copolyamide (CPA) oligomers. The effects of content and molecular weight of CPA segments on the thermal and mechanical properties of TPU were studied. PEA segments showed enhanced crystallization when some of the hard segments were replaced by CPA segments, showing weaker CPA–PEA interaction. The crystallinity of the hard segments was reduced, probably due to some interaction and phase mixing between hard and CPA segments. The modulus of TPU also decreased, more markedly with CPA segments of higher molecular weight.     

Rheological and mechanical properties of poly (ethylene acrylic acid) and low density polyethylene blends

Rheological properties of poly (ethylene‐acrylic acid) (PEA) and low density poly ethylene (LDPE) blends having varied amounts of LDPE from 0 to 100% have been evaluated at different temperatures (115, 120, and 130°C) and shear rates (61.33–613.30 s^?1) using a Monsanto processability tester. A reduction in the melt viscosity of the PEA/LDPE blends was noticed with increasing the shear rate. The observed positive deviation in the experimental melt viscosities of the blends is an indication of the synergy present in the blends during melt processing. The activation energy (E_a) of flow calculated using Arrhenius relation for PEA, LDPE, and their respective blends lies in the range 29.98–40.56 kJ mol^?1. The experimental activation energy of flow of the blends was higher than that obtained from the additivity rule. Highest activation energy was noticed for the blends containing 60–80% by weight of LDPE in PEA/LDPE blends, which is an indication for the miscibility of the blends at these ratios. The physicomechanical properties such as density, tensile behavior, tear strength, and hardness (Shore A) of PEA, LDPE, and their blends have been evaluated as a function of varying amounts of LDPE. The obtained physicomechanical properties of the PEA/LDPE blends lie in between that of pure polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polyester–polycarbonate blends. V. Linear aliphatic polyesters

Polycarbonate blends with the linear aliphatic polyesters poly(ethylene succinate) (PES), poly(ethylene adipate) (PEA), poly(1,4-butylene adipate) (PBA), and poly(hexamethylene sebacate) (PHS) were prepared by solution casting. Blends containing PES, PEA, and PBA exhibited a single T_g by DSC and thus form a single, miscible amorphous phase with polycarbonate. However, blends containing PHS exhibited only partial miscibility. Crystallinity of the polyesters was reduced by mixing with polycarbonate; however, plasticization by the polyesters induced crystallization of the polycarbonate. Miscibility in these systems is the result of an exothermic heat of mixing stemming from an interaction of the carbonyl dipole of the ester group with the aromatic carbonate. The effect of polyester structure on miscibility with polycarbonate is interpreted by and correlated with heats of mixing obtained by direct calorimetry of low molecular weight liquid analogs of the polymers.     

Physical properties of poly(ethylene adipate)/low-density polyethylene blends

Mechanical and rheological properties of poly(ethylene adipate) (PEA)/low-density polyethylene (LDPE) blends were investigated. DSC results showed that there is no miscibility between PEA and LDPE. Tensile strength decreases with increasing PEA content, while the modulus increases. Elongation at break decreases with increasing PEA content. A rheological constitutive equation was used for describing and predicting the steady-state shear viscosity of PEA/LDPE blend. The suggested equation was successfully able to describe and predict viscosity of the blend as functions of shear rate and temperature. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1745–1750, 1997     

Synthesis and characterization of poly(esteramide‐urethane) from linseed oil as anticorrosive coatings

Ethylene diamine polyesteramide (Ed‐PEA) was synthesized from N, N‐bis (2‐hydroxy ethyl) linseed oil fattyamide and ethylene diamine tetra acetic acid through condensation polymerization. It was further treated with toluylene 2,4‐diisocyanate (TDI) in different weight percentage to obtain urethane‐modified polyesteramide (Ed‐UPEA). The structural elucidation of Ed‐PEA and Ed‐UPEA were carried out by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopic techniques. Thermal studies of these resins were carried by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The coatings of urethane‐modified polyesteramide were prepared on mild steel strips and their anticorrosive behavior of in acid, alkali, water, and xylene were investigated. Thermal stability performance suggests that the system could be safely used upto 200°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Chelating resins supporting dithiocarbamate and methylthiourea groups in adsorption of heavy metal ions

Two different sulfur atom containing functional groups were introduced into poly(styrene-g-ethylene glycols), PSR-ET (13) OH, consisting of a cross-linked polystyrene backbone grafted with linear poly(ethylene glycol) chains. Reaction of an amino derivative of the polymeric substrate with carbon disulfide and methylisothiocyanate produced new chelating resins of dithiocarbamate type, PSR-ET (13) CS₂Na, and methylthiourea type, PSR-ET (13) TU, respectively. The adsorption behavior of these resins was studied toward Hg(II), Cd(II), Cu(II), and Pb(II) ions in different experimental conditions. The order of metal adsorption for dithiocarbamate-supported resins was Hg(II) > Pb(II) ? Cd(II) > Cu(II) and for methylthiourea-supported resins was Hg(II) ? Cu(II) > Cd(II) ? Pb(II). Different regeneration methods were performed with the dithiocarbamate and methylthiourea resins; the former was regenerated by complete mineralization of the metal complexes, the latter by treatment with a solution of 6 N HCl and 10% of thiourea. © 1994 John Wiley & Sons, Inc.     

Synthesis and Catalytic Activities of Silica-Supported Multifunctional Azo-Containing Schiff Base Complexes with Cu(II), Co(II), Ni(II) and Mn(II)

A novel 4-((5-formyl-2,4-dihydroxyphenyl)diazenyl)benzylphosphonic acid (FPABP) ligand was synthesized and bound to silica-gel which was activated with 3-aminopropyltriethoxysilane (APTES). Cu(II), Co(II), Ni(II) and Mn(II) complexes of silica-supported ligand (FDPDABP) were synthesized. The ligand and its complexes were characterized by using NMR, FT-IR, elemental analysis, ICP-OES and scanning electron Microscope (SEM). Catalytic properties of the complexes were investigated for the selective oxidation of cyclohexane under microwave power. SiO₂-FDPDABP-Cu(II) complex showed good catalytic activitiy for the selective oxidation of cyclohexane to cyclohexanol with 35.61% yield and cyclohexanone with 7.74% yield.     

Water‐soluble amine and imine polymers with the ability to bind metal ions in conjunction with membrane filtration

The commercial polymers poly(ethylene imine) (PEI), poly(ethylene imine epichlorohydrin), and poly(dimethylamine‐co‐epichlorohydrin) were purified and fractionated by ultrafiltration. Their metal‐ion‐binding properties with respect to different ligand groups and the effect of the concentration on the retention properties were investigated. The amine ligands of the polymers formed the most stable complexes with the metal ions. In general, there was an effect of the pH and polymer fraction size on the retention properties. As the pH and polymer fraction size increased, the affinity to bind metal ions also increased. PEI had the highest metal‐retention values, particularly at higher pHs, at which the amine groups were nonprotonated and could coordinate easily with the metal ions. Only Pb(II) was poorly retained. The affinity for all the metal ions, except Pb(II), increased significantly at pH 5. The metal‐ion retention decreased quickly as the filtration factor increased, except for Cu(II), Co(II), Ni(II), Cd(II), and Zn(II) ions, which were retained by over 40% at a filtration factor of 4. For other metal ions such as Pb(II), Ca(II), and Mg(II), only 10% remained bound to the polymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 222–231, 2005     

Crystallization kinetics and crystalline structure of biodegradable Poly(ethylene adipate)

The crystallization kinetics, morphology and crystalline structure of biodegradable poly(ethylene adipate) (PEA) with high and low molecular weights (HMW, LMW) were systematically investigated. The crystallization kinetics obtained from differential scanning calorimetry analysis indicated that both the primary and secondary crystallizations occur during the isothermal and non-isothermal crystallization processes for HMW and LMW PEA samples. Under the same crystallization condition, LMW PEA was found to crystallize faster than HMW PEA. The PEA sample forming the ring-band spherulite presents a higher Avrami exponent value (n) than that without the ring-band spherulite, due in part to the different crystal growth mechanism. From the results of wide angle X-ray diffraction and Fourier transform infrared spectroscopy, it was confirmed that the crystalline structure of PEA is not dependent on the crystallization temperature (T_c) and MW. From the in-situ FTIR investigation of the crystallization kinetics, it is concluded that, during the isothermal crystallization process at 42 °C, the structural rearrangement of the ester group precedes that of the CC backbone.     

聚醚胺基聚脲的合成及其性能

以乙二胺、氯乙醇和环氧氯丙烷为原料制备线型聚醚胺(PEA),分别用脂肪族二异氰酸酯(IPDI或HDI)与PEA进行交联,制得网络结构聚脲P1A, P1, P1B和P2,研究了聚脲的结构和热分解性能及其在水溶液中的酶促降解性. 结果表明,聚合物的热分解过程主要有2个阶段：由酰胺键断裂引起的失重,P1A, P1, P1B和P2失重速率最大时的温度分别为337.3, 367.6, 372.7和367.4℃;由PEA主链断裂引起的失重,P1A, P1, P1B和P2失重速率最大时的温度分别为440.5, 422.5, 444.9和482.7℃. P1在有木瓜蛋白酶的PBS缓冲溶液中(pH=7.42), 60 d后失重率超过40%. 随着交联剂IPDI用量增加,聚合物的热分解温度提高,生物降解速率降低.     

Beneficial influence of nanocarbon on the aryliminopyridylnickel chloride catalyzed ethylene polymerization

A series of 1-aryliminoethylpyridine ligands (L1―L3) was synthesized by condensation of 2-acetylpyridine with 1-aminonaphthalene, 2-aminoanthracene or 1-aminopyrene, respectively. Reaction with nickel dichloride afforded the corresponding nickel (II) chloride complexes (Ni1–Ni3). All compounds were fully characterized and the molecular structures of Ni1 and Ni3 are reported. Upon activation with methylaluminoxane (MAO), all nickel complexes exhibit high activities for ethylene polymerization, producing waxes of low molecular weight and narrow polydispersity. The presence of multi-walled carbon nanotubes (MWCNTs) or few layer graphene (FLG) in the catalytic medium can lead to an increase of productivity associated to a modification of the polymer structure.     

A spectroscopic study of Cu(II)-complexes of chelating resins containing nitrogen and sulfur atoms in the chelating groups

The structures of different Cu(II)-thiol, dithiocarbamate, methylthiourea and amino complexes have been investigated on the basis of their spectroscopic properties. The influence of the chemical structure, both the nature of the functional groups and the spacers, on the resin chelating behaviour towards Cu(II) ions in diluted solution has been evaluated. The resins are macroporous polystyrene–divinylbenzene polymer functionalized with two spacer groups, poly(ethylene glycol) and poly(ethylene imine) chains, supporting thiol, dithiocarbamate, methylthiourea and amino groups. Electron paramagnetic resonance (EPR) was employed to show the coordination of Cu(II) ions into the complexes. Cu(II)-dithiocarbamate complexes have a square planar coordination with two dithiocarbamate groups bound to the metal. The resins with methylthiourea as functional group form Cu(II)-complexes in tetragonal symmetry with four nitrogen atoms as equatorial ligands. Further, a partial reduction of Cu(II) to diamagnetic Cu(I) with formation of Cu(I)-methylthiourea complexes, where copper is S-bonded to the methylthiourea group, could be suggested. In Cu(II)-thiol complexes, Cu(II) ions are bound through sulfur bridges.