Synthesis and properties of fluorescent light‐emitting polyamide hybrids with reactive nanosilica by epoxide functionalization

A series of poly(carbazole‐quinoxaline‐amide)s (PCQAs) containing phenyl and long alkyl chain as pendants was synthesized from polycondensation between a new diamine with a synthesized and several commercial dicarboxylic acids using Yamazaki's method. PCQAs had inherent viscosities and weight average molecular weights ( ) in the range of 0.48–0.62 dL g^?1 and 51,600–58,500 g mol^?1, respectively. These luminescent polymers are readily soluble in a variety of organic solvents and formed low‐colored and tough thin films. In this study, silane modified SiO₂ (mSiO₂) nanoparticles were prepared, characterized and used with PCQAs in preparation of nanocomposites via solution blending method. The interfacial interaction strength between mSiO₂ and the polymer–matrix enhanced thermal stability (T_10%, from 463°C to 500°C) and mechanical strength (from 100 MPa to 150 MPa) for composite containing 30 wt % mSiO₂ in comparison with the pure polyamide. These materials showed good ability for extraction–elimination of metal ions such as Cr⁶⁺, Cr³⁺, Co²⁺, Zn²⁺, Pb²⁺, Cd²⁺, and Hg²⁺ from aqueous solutions either individually or in the mixture at various pH. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40219.     

EFFECT OF NANOSILICA ON THE KINETICS OF CURE REACTION AND THERMAL DEGRADATION OF EPOXY RESIN

Nanocomposites from nanoscale silica particles (NS), diglycidylether of bisphenol-A based epoxy (DGEBA), and 3,5-diamino-N-(4-(quinolin-8-yloxy) phenyl) benzamide (DQPB) as curing agent were obtained from direct blending of these materials. The effect of nanosilica (NS) particles as catalyst on the cure reaction of DGEBA/DQPB system was studied by using non-isothermal DSC technique. The activation energy (Ea) was obtained by using Kissinger and Ozawa equations.The Ea value of curing of DGEBA/DQPB/10% NS system showed a decrease of about 10 kJ/mol indicating the catalytic effect of NS particles on the cure reaction. The Ea values of thermal degradation of the cured samples of both systems were 148 kJ/mol and 160 kJ/mol, respectively. The addition of 10% of NS to the curing mixture did not have much effect on the initial decomposition temperature (Ti) but increased the char residues from 20% to 28% at 650℃.     

Synthesis of soluble and thermally stable polyimides from 3,5‐diamino‐N‐(4‐(8‐quinolinoxy) phenyl) aniline and various dianhydrides

Three novel polyimides (PIs) having pendent 4‐(quinolin‐8‐yloxy) aniline group were prepared by polycondensation of a new diamine with commercially available tetracarboxylic dianhydrides, such as pyromellitic dianhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bicyclo[2.2.2]‐oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride. These PIs were characterized by FTIR, ¹H NMR, and elemental analysis; they had high yields with inherent viscosities in the range of 0.4–0.5 dl g⁻¹, and exhibited excellent solubility in many organic solvents such as N,N‐dimethyl acetamide, N,N′‐dimethyl formamide, N‐methyl pyrrolidone (NMP), dimethyl sulfoxide, and pyridine. These PIs exhibited glass transition temperatures (T_g) between 250 and 325° C. Their initial decomposition temperatures (T_i) ranged between 270 and 450°C, and 10% weight loss temperature (T₁₀) up to 500°C with 68% char yield at 600°C under nitrogen atmosphere. Transparent and hard polymer films were obtained via casting from their NMP solutions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of soluble and thermally stable polyamides from diamine containing (quinolin‐8‐yloxy) aniline pendant group

A novel diamine monomer having pendant 4‐(quinolin‐8‐yloxy) aniline group was successfully synthesized via aromatic substitution reaction of 8‐quinolinol with p‐fluoronitrobenzene followed by Pd/C catalyzed hydrazine reduction, amidation reaction between 4‐(quinolin‐8‐yloxy) aniline and 3,5‐dinitrobenzoylcholoride followed by Pd/C catalyzed hydrazine reduction. The diamine monomer was fully characterized by using FTIR, ¹H‐NMR, ¹³C‐NMR, and elemental analysis. The diamine monomer was polymerized with various aromatic and aliphatic dicarboxylic acids to obtain the corresponding polyamides. The polyamides had inherent viscosity in the range of 0.30–0.41 dL/g and exhibited excellent solubility in the polar aprotic solvents such as DMAc, NMP, N,N‐dimethylformamide, Pyridine, and DMSO. The glass transition temperatures (T_g) of the polymers are high (up to 313°C) and the decomposition temperatures (T_i) range between 200 and 370°C, depending on the diacids residue in the polymers backbone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study properties of nanocomposites prepared with new polyimides and reactive nanosilica by epoxide functionalization

In this article, new types of organosoluble polyimides, poly(carbazole‐quinoxaline‐imide)s (PCQI), were synthesized and used in preparation of nanocomposites with modified nanosilica (mNS). The synthesized polyimides bearing different solubilizing functional moieties were casted into thin films at room temperature. SiO₂ nanoparticles were surface modified with γ‐glycidoxypropyltriethoxysilane (GPTES) to obtain mNS containing epoxide functional groups. The PCQI/mNS nanocomposites were prepared via cure reaction of epoxide groups and polymer functional units. The PCQIs and nanocomposites films were tested for different properties including thermal using TGA and DMTA, mechanical, thermomechanical, photophysical, solubility, water uptake, and metal ions adsorption. The strong chemical bonding between mNS particles and polymer matrix reduced solubility of nanocomposite and enhanced thermal stability in term of 10% weight loss temperature (T_10%, from 509°C to 582°C) and tensile strength (from 110 MPa to 155 MPa). These polyimides and nanocomposites were also efficient chelating agents for removal of metal ions such as , Cr³⁺, Pb²⁺, Cd²⁺, and Hg²⁺ from aqueous solutions either individually or in the mixture and at different pH values. POLYM. COMPOS. 36:545–555, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of new fluorescent polyimides bearing 1,2,4-triazole and 1,2-diaryl quinoxaline: Study properties and application to the extraction/elimination of metallic ions from aqueous media

In this article, synthesis and characterization of triazole-based polyimides for solid-phase extraction of metal cations is described. For this purpose, new aromatic diamines containing 1,2,4-triazole and substituted 1,2-diaryl quinoxaline units were synthesized and used in polycondensation reaction with aromatic dianhydrates to yield poly(triazole-imide)s (PTAI)s. These polymers had inherent viscosities in the range of 0.58–0.62 dL/g and were readily soluble in a variety of organic solvents; they formed low-colored and tough thin films via solution casting. The PTAIs exhibited T_g between 280 and 338 °C, and their 10% weight loss temperatures were in excess of 540 °C with up to 76% char yield at 700 °C in N₂. These polymers emitted green or blue fluorescence in dilute NMP solution and in the solid state. The triazole groups in the polymer chain were efficient chelating/host units for heavy metal ions. One of these polymers, PTAI(1b), was investigated for its extraction capability for environmentally deleterious metal ions such as Cr^VI, Cr^III, Co^II, Zn^II, Pb^II, Cd^II, Hg^II and Mn^II from aqueous solutions either individually or in the mixture and at different pH values.