Thermally Stable and Organo-soluble Polyamides Containing Triazine Rings and Ether Linkages in the Main Chain: Synthesis and Characterization

In order to synthesize new polyamide(PA) 5 and copolyamides(Co PA) 7a-7d, a new-type of dicarboxylic acid containing triazine ring was successfully synthesized from 2,4-dichloro-6-methoxy-s-triazine 1 and 4-aminobenzoic acid. New polyamide 5 containing triazine moiety was prepared from 4,4'-(6-methoxy-1,3,5-triazine-2,4-diyl)bis(azanediyl)dibenzoic acid 3 and 4,4′-diaminodiphenylether by direct polycondensation reaction. Then new series thermally stable copolyamides 7a-7d with high solubility in common organic solvents were synthesized from the direct polycondensation reaction of diacid 3 as a first monomer, aliphatic-aromatic diacids 6a-6d as second diacids and 4,4′-diaminodiphenylether. All of the above polymers were fully characterized by 1H-NMR and FTIR spectroscopy, elemental analysis(CHN), inherent viscosity, solubility tests, gel permeation chromatography(GPC), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). The resulted Co PAs 7a-7d have shown good inherent viscosities, solubility and thermal properties.     

Influence of imide functionalized organo‐modified Mg‐Al layered double hydroxide on the thermal and mechanical properties of new aliphatic‐aromatic poly (amide‐imide)

A new dicarboxylic acid modified Mg‐Al LDH (DLDH) containing imide groups was prepared and its effects on the thermal and mechanical properties of the new synthesized aliphatic‐aromatic poly (amide‐imide) (PAI) were investigated via preparation of PAI/nanocomposite films by solution casting method. The results of X‐ray diffraction (XRD), field emission‐scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM) showed a uniform dispersion for LDH layers into the PAI matrix. For comparison, the effects of polyacrylic acid‐co‐poly‐2‐acrylamido‐ 2‐methylpropanesulfonic acid (PAMPS‐co‐PAA) modified Mg‐Al LDH (ALDH) on the PAI properties were also studied. The thermogravimetric analysis (TGA) results exhibited that the temperature at 5 mass% loss (T₅) increased from 277 °C to 310 °C for nanocomposite containing 2 mass% of DLDH, while T₅ for nanocomposite containing 2 mass% of ALDH increased to 320 °C, along with the more enhancement of char residue compared to the neat PAI. According to the tensile test results, with 5 mass% DLDH loading in the PAI matrix, the tensile strength increased from 51.6 to 70.8 MPa along with an increase in Young's modulus. Also the Young's modulus of PAI nanocomposite containing 5 mass% ALDH reduced from 1.95 to 0.81 GPa.     

Preparation and Characterization of New Optically Active Poly(amide-imide)s from N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine and Aromatic Diamines

Five new optically active aromatic poly(amide-imide)s (PAIs) 5a–e were prepared from a direct polycondensation reaction of a new diacid of N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-isoleucine 3 with various aromatic diamines 4a–e in a medium consisting of triphenyl phosphite (TPP), calcium chloride (CaCl₂), pyridine (Py) and N-methyl-2-pyrrolidone (NMP). The polycondensation reaction produced a series of novel poly(amid-imide)s 5a–e in quantitative yields with inherent viscosities of 0.39–0.51 dL/g. The resulting polymers were fully characterized by means of ¹H-NMR, FT-IR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of them were investigated using TGA/DTG and differential scanning calorimeter (DSC). 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-isoleucine 2 in acetic acid solution.     

Novel Flame‐Retardant and Thermally Stable Poly(Amide‐imide)s Based on Bicyclo[2,2,2]oct‐7‐Ene‐2,3,5,6‐Tetracarboxylic Diimide and Phosphine Oxide in the Main Chain: Synthesis and Characterization

Six novel poly(amide‐imide)s PAIs 5a‐f were synthesized through the direct polycondensation reaction of six chiral N,N′‐(bicyclo[2,2,2]oct‐7‐ene‐tetracarboxylic)‐bis‐L‐amino acids 3a‐f with bis(3‐amino phenyl) phenyl phosphine oxide 4 in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), triphenyl phosphite (TPP), calcium chloride (CaCl₂) and pyridine. The polymerization reaction produced a series of flame‐retardant and thermally stable poly(amide‐imide)s 5a‐f with high yield and good inherent viscosity of 0.39–0.83 dLg^?1. The resultant polymers were fully characterized by means of FTIR, ¹H NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Thermal properties and flame retardant behavior of the PAIs 5a‐f were investigated using thermal gravimetric analysis (TGA and DTG) and limited oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers show good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that resultant polymers exhibited good flame retardant properties. N,N′‐(bicyclo[2,2,2]oct‐7‐ene‐tetracarboxylic)‐bis‐L‐amino acids 3a‐f were prepared in quantitative yields by the condensation reaction of bicyclo[2,2,2]oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride 1 with L‐alanine 2a , L‐valine 2b , L‐leucine 2c , L‐isoleucine 2d , L‐phenyl alanine 2e and L‐2‐aminobutyric acid 2f in acetic acid solution. These polymers can be potentially utilized in flame retardant thermoplastic materials.     

OPTICALLY ACTIVE AND FLAME-RETARDANT POLY(AMIDE-IMIDE)S BASED ON PHOSPHINE OXIDE MOIETY AND N,N′-(PYROMELLITOYL)BIS-L-AMINO ACID IN THE MAIN CHAIN:SYNTHESIS AND CHARACTERIZATION

<正>Six new optically active and flame-retardant poly(amide-imide)s PAIs 5a-5f containing phosphine oxide moiety as a flame-retardant unit in the main chain were synthesized from direct polycondensation reaction of six chiral N,N′-(pyromellitoyl)-bis-L-amino acid 3a-3f with bis(3-aminophenyl)phenyl phosphine oxide 4 in a medium consisting of N-methyl-2-pyrrolidone(NMP),triphenyl phosphite(TPP),calcium chloride(CaCl_2) and pyridine.The polymerization reactions produced a series of optically active poly(amide-imide)s with good yield and good inherent viscosity of 0.34-0.70 dLg~(-1).The resulted polymers were fully characterized by means of FTIR and ~1H-NMR spectroscopy,gel permeation chromatography(GPC),elemental analyses,inherent viscosity and solubility tests.Thermal properties and flame-retardant behavior of the PAIs 5a-5f were investigated using thermal gravimetric analysis(TGA and DTG) and limiting oxygen index(LOI).Data obtained by thermal analysis(TGA and DTG) revealed that these polymers showed good thermal stability.Furthermore,high char yield in TGA and good LOI values indicated that the resulting polymers were capable of exhibiting good flame retardant properties.N,N′-(pyromellitoyl)-bis-L-amino acids 3a-3f were prepared in quantitative yields by the condensation reaction of pyromellitic dianhydride(1,2,4,5-benzenetetracarboxylicacid-1,2,4,5-dianhydride) 1 with L-alanine 2a,L-valine 2b,L-leucine 2c,L-isoleucine 2d,L-phenyl alanine 2e and L-2-aminobutyric acid 2f in acetic acid solution.     

Adaptive iterative multiscale finite volume method

The multiscale finite volume (MSFV) method is a computationally efficient numerical method for the solution of elliptic and parabolic problems with heterogeneous coefficients. It has been shown for a wide range of test cases that the MSFV results are in close agreement with those obtained with a classical (computationally expensive) technique. The method, however, fails to give accurate results for highly anisotropic heterogeneous problems due to weak localization assumptions. Recently, a convergent iterative MSFV (i-MSFV) method was developed to enhance the quality of the multiscale results by improving the localization conditions. Although the i-MSFV method proved to be efficient for most practical problems, it is still favorable to improve the localization condition adaptively, i.e. only for a sub-domain where the original MSFV localization conditions are not acceptable, e.g. near shale layers and long coherent structures with high permeability contrasts. In this paper, a space–time adaptive i-MSFV (ai-MSFV) method is introduced. It is shown how to improve the MSFV results adaptively in space and simulation time. The fine-scale smoother, which is necessary for convergence of the i-MSFV method, is also applied locally. Finally, for multiphase flow problems, two criteria are investigated for adaptively updating the MSFV interpolation functions: (1) a criterion based on the total mobility change for the transient coefficients and (2) a criterion based on the pressure equation residual for the accuracy of the results. For various challenging test cases it is demonstrated that iterations in order to obtain accurate results even for highly anisotropic heterogeneous problems are required only in small sub-domains and not everywhere. The findings show that the error introduced in the MSFV framework can be controlled and improved very efficiently with very little additional computational cost compared to the original, non-iterative MSFV method.     

Thermal,combustion and optical properties of new polyimide/ODA-functionalized Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanocomposites containing xanthene and amide groups

Polypropylene (PP), due to its chemical stability, is considered one of the main responsible of the increasing amount of plastic wastes on earth. To overcome this problem and to reduce the dependence of oil feedstocks, the use of lignocellulosics as fillers or reinforcements in thermoplastic materials has been increasing enormously in the last decades. In the present work, Liquid Wood (a mixture of cellulose, hemp, fax and lignin) was used to prepare, by mechanical mixing followed by thermal extrusion, blends of various PP/Liquid Wood ratios. Differential scanning calorimetry and thermogravimetric analysis experiments were performed in order to verify whether and how much the composition of the blends affects the thermal properties of the obtained compounds. Both calorimetric and thermogravimetric results indicate that the application of PP as a matrix does not limit the processing temperature of Liquid Wood, which may lead to a perfect marketable composite from these components. The addition of Liquid Wood also resulted in enhanced mechanical properties for the PP/Liquid Wood blends.     

Synthesis and characterization of new thermally stable poly(amide-imide)s based on bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide and aromatic diamines

N,N′-bis-(4-carboxyphenyl)bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide was prepared by reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic dianhydride with p-aminobenzoic acid in a mixture of acetic acid and pyridine (3: 2). Polycondensation of N,N′-bis-(4-carboxyphenyl)bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide with six different aromatic diamines produced a series of new poly(amide-imide)s (PAIs) in high yields with inherent viscosities between 0.49–0.95 dl/g. All PAIs were characterized by means of elemental analysis, viscosity measurement, solubility test, FTIR spectroscopy and ¹H-NMR spectroscopy. Dynamic TGA of PAIs shows 10% weight loss temperatures from 410 to 435°C under nitrogen.     

Synthesis and characterization of organo-soluble poly(amide-imide)s based on 1,2-bis[4-(trimellitimido)phenoxy]ethane and aromatic diamines

<正>New organo-soluble poly(amide-imide)s(PAIs) 8a-8f were prepared from newly synthesized 1,2-bis[4,4'-(trimellitimido) phenoxy]ethane 6 via direct polycondensation with various aromatic diamines.The diacid 6 was synthesized by the condensation reaction of 12-bis[4-atninophenoxy]ethane 4 with trimellitic anhydride 5 in acetic acid.All polymers were obtained in quantitative high yields with inherent viscosities of 0.48-0.61 dL/g.All of these polymers were highly soluble in organic solvents such as,N-methyl-2-pyrrolidone(NMP),dimethylformamide(DMF),N,N'-dimethylacetamide (DMAc) and dimethylsulfoxide(DMSO) at room temperature and were fully characterized by means of NMR spectroscopy, FTIR spectroscopy,elemental analyses,inherent viscosity,solubility test,specific rotation,differential scanning calorimetry (DSC) and thermogravimetric analysis(TGA).     

Organosoluble Aliphatic-Aromatic Poly（ether-amide）s Based on Pyridine Moiety in the Main Chain： Synthesis,Characterization and Thermal Studies

A series organosoluble and heterocyclic poly（ether-amide）s （PEA）s were synthesized from a new diamine containing pyridine moiety and four aliphatic-aromatic dicarboxylic acids by direct polycondensation reactions. Dicarboxilic acids 4a-4d containing ether groups were synthesized in two step reactions. At first, dialdehydes 3a-3d were synthesized from four dibromo alkanes la-ld and 4-hydroxybenzaldehyde 2, then dicarboxilic acids 4a-4d were synthesized from dialdehydes 3a-3d and malonic acid in a solvent free reaction. On the other hand, the new diamine 8 containing pyridine ring was synthesized in two step reactions. The structures of synthesized monomers and polymers were proven by FTIR, NMR spectroscopy and elemental analysis. Also all of the above polymers were fully characterized by inherent viscosity, solubility tests, gel permeation chromatography （GPC）, differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. The resulted PEAs have shown good inherent viscosities, solubility and thermal properties.