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In this study, mechanical, thermal, and morphological properties of the nanocomposites fabricated with the optimized blend of poly(ether ether ketone) (PEEK) and poly(ether sulfone) (PES) incorporated with nanobarium titanate (BT) were investigated. The optimized blend was based on the mechanical and thermal properties of the PEEK and PES in the ratio of 75 : 25 wt %. Nanoparticles were incorporated into the optimized blend with the help of twin-screw extruder. The concentration of nano-BT was varied from 2 to 6 wt % (0.41–1.28 vol %). With the increase in the nanosized BT concentrations, the tensile strength, tensile modulus, and elongation at break increased, whereas the crystallinity of the nanocomposites calculated by using differential scanning calorimetry method was found to decrease marginally. Morphological studies were carried out using scanning electron microscopy. The nanocomposites were evaluated by using theoretical predictive models according to “Pukanszky model” applicable to tensile strength and “Takayanagi's model” and “Guth and Smallwood model” applicable to tensile modulus. Upper and lower boundary of Hashin–Shtrikman model as well as Paul's model, applicable to tensile modulus, were also used to compare the experimental data. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In this article, we report the synthesis and characterization of chiral copolymers containing a photoactive azobenzene pendant group. The chiral copolymers of (S)-N-(1-phenyl ethyl) methacrylamide (S-NPEMAM) and disperse red 1 methacrylate (DR1MA) with two different feed compositions were synthesized by free-radical polymerization with 2,2′-azobisisobutyronitrile as an initiator. The purified chiral copolymers, poly[(S)-N-(1-phenyl ethyl) methacrylamide-co-disperse red 1 methacrylate], were characterized by Fourier transform infrared spectroscopy, NMR, ultraviolet–visible spectroscopy, and gel permeation chromatography analyses. The photoluminescence and chiroptical properties of the copolymers were evaluated. Induced circular dichroism (CD) was observed in the CD spectra, which arose because of the exciton splitting originated by the cooperative interactions between the pendant azobenzene chromophore of DR1MA and the benzene ring of the chiral monomer. The glass-transition temperatures of the chiral copolymers were observed to be above 117°C, and the chiral copolymers were thermally stable up to 250°C. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Novel nanocomposites of barium hexaferrite- and fullerene-containing polyurethane were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and energy-dispersive X-ray diffraction. The nanoparticles showed good dispersion in the polyurethane matrix. Their thermal, mechanical, and electromagnetic absorbance properties were studied. The complex permeability and permittivity were measured in the frequency range of 8.2–12.4 GHz. The maximum reflection loss of the nanocomposites was found to increase with increasing the ferrite content from 1% to 5%, with maximum value of −7.5 dB at only 5% composition. The incorporation of nanofiller not only imparts mechanical strength to the nanocomposite but also shows good radar-absorbing properties at only 5% filler concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A series of novel semi-2-interpenetrating polymeric networks (semi-2-IPNs) were prepared through blending in solution using two different polyimides, biscitraconamic acid as a precursor of biscitraconimide (MBMI) with various proportions of polyetherimide (PEI) to achieve optimum properties. Biscitraconamic acid was prepared by reacting citraconic anhydride (CA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) and bis(3-aminopropyl)phenyl phosphine (BAPPP) and it was characterized by differential scanning calorimetry (DSC), FTIR, and 1H-NMR spectroscopy. Both biscitraconamic acid and PEI were blended in N,N-dimethylacetamide (DMAc) solution, casted and thermally cured up to 300°C to give semi-2-IPNs. The MBMI/PEI semi-IPN systems were characterized by UV-Vis spectroscopy, FTIR spectroscopy and thermal techniques. The phase morphology, isothermal aging, and water uptake of semi-IPN systems have also been studied. The morphological studies on phase distribution were investigated by scanning electron microscopy (SEM). Thermal performance of MBMI/PEI semi-IPN systems were evaluated by DSC and thermo gravimetric analysis (TGA). All the compositions of semi-IPN polyimide system were stable up to 400°C and their thermal stability increased with increase in the content of PEI. Isothermal aging studies done at 300°C for various time periods showed good thermo-oxidative stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In this study, mechanical properties such as tensile properties, flexural properties, and Izod impact strength of poly(ether ether ketone) (PEEK) and poly(ether ketone) (PEK) blends at PEK concentration from 0 to 0.42 volume fraction were studied. The blends of PEEK and PEK of different compositions were prepared by extrusion in a single-screw extruder. With increase in the PEK concentrations, the tensile strength, flexural strength, and modulus increased whereas the tensile modulus and the impact strength decreased. Homogeneous dispersion and adhesion of PEK in PEEK was shown by the morphological studies. Crystallinity of blends influenced the tensile modulus and the impact strength. Using simple models to relate normalized tensile parameters where the data were divided by the crystallinity of the blends and of the PEEK matrix, respectively, supported the experimental results. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A series of epoxy/polymethyl methacrylate (E/PMMA) blends was synthesized through impregnation polymerization of methyl methacrylate at concentrations ranging (0–1.5 phr) into diglycidyl ether of bisphenol-A (0.1 mol) in presence of 2,2-azobisisobutyronitrile (2 × 10−2 mol) at 3000 psi, (60–90 ± 1)°C for 3 h in supercritical carbon dioxide, followed by curing of treated epoxy with triethylene tetramine (10 phr) at (40 ± 1)°C. The progress of all such impregnation polymerization reactions was monitored rheoviscometrically. Formation of E/PMMA blends was ascertained through of PMMA mass uptake (%) into epoxy, UV–vis and FTIR spectra, and TEM. With PMMA mass uptake (%), compression strength and resistance against wear of E/PMMA blends were increased with simultaneous decrease in their Rockwell hardness (R scale), charpy impact, and tensile strength, respectively. All E/PMMA blends have shown nonuniform photoelastic behavior at applied load ranging 4–20 kgf and significant stability against thermooxidation with Tg/Tm and char yield (%) ranging 0.53–0.59, 29.31–31.66, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1303–1310, 2007

Diffusion of seawater in unsaturated poly- ester resin (UPR) and its glass fiber reinforced composite in the presence of titanium dioxide has been studied by sorption method. Incorporation of glass and TiO2 to UPR alters the seawater diffusion process from Fickian to non- Fickian type. The dual mode sorption model is used to separate Fickian-controlled and relaxation-controlled diffu- sion in case of UPR-T, UPR-G, and UPR-GT. The presence of TiO2 seems to stabilize UPR and its glass reinforced samples but an increase in the rate of seawater diffusion is observed for these systems. The free volume determined from positron lifetime measurements support the diffusion data in these systems. Results further indicate that the con- tribution to diffusion in the later stages of sorption is due to the increased contribution from the interfaces. The plas- ticizing effect of TiO2 is clearly seen even in the glass rein- forced composite. DMA results show an increase in flexi- bility because of TiO2 presence both in the neat as well as glass reinforced resin which is well supported by decrease in Tg value from DSC data. 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2784-2794, 2006

A series of polyimides were synthesized from new diamine, Bis [4,4′-amino-5,5′ trifluoromethyl phenoxy-(hexafluoro isopropylidine) phenoxy phenyl] benzonitrile [BATFB] and various aromatic tetracarboxylic anhydrides by thermal and chemical imidization routes. The BATFB was synthesized in two steps by nucleophilic displacement reaction of 2,6-dichloro benzonitrile, 4,4′-(hexafluoro isopropylidine) diphenol and 2-amino-5-fluoro benzotrifluoride in the presence of anhydrous potassium carbonate in N,N′-dimethyl acetamide (DMAc) and the structure was confirmed by FTIR spectroscopy and CHNSO analyzer. The polymers were characterized by FTIR spectroscopy and thermal analysis were performed by differential scanning calorimetry and thermogravimetric analysis methods. The prepared polyimides had glass transition temperatures between 230 and 290°C and their 10% weight loss were recorded in the range 550–590°C in N2 atmosphere. Majority of polymers are found to be soluble in most of the organic solvents such as DMSO, DMF, DMAc, m-cresol, and THF even at room temperature and few becomes soluble on heating. The prepared polyimides showed water uptake values 0.34–0.54 wt % at room temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3455–3461, 2006

Thermochromic poly(vinyl alcohol) (PVA)-based material was synthesized and an extensive study of its thermochromic behavior with respect to response time was carried out. It was observed that it is possible to manipulate the response time by keeping control over chemical and physical parameters. The response time, which is the most important property of a smart material, has in this case been found to be very much influenced by rate of heat transfer into the material. Different compositions of the thermochromic material and their corresponding response time with respect to rate of heat transfer were studied and correlated. First, a theoretical equation was derived and later on it was experimentally verified to quantify the response time in PVA–metal complex-based thermochromic systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4832–4834, 2006

Ten nadicimide/methyl nadicimide end-capped oligomeric resins were prepared by reacting endo-5-norbornene-2,3-dicarboxylic acid anhydride (methyl nadic anhydride), pyromellitic dianhydride (PMDA)/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA)/2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6F), and bis(3-aminophenyl) methyl phospine oxide (BAP) in glacial acetic acid/ acetone. Structural characterization of the resins was done by elemental analysis, IR, and 1 H-NMR. Multistep decomposition was observed in the TG scan of uncured resins in a nitrogen atmosphere. Residual weight at 800°C depended on the structure and ranged between 25 and 51%. Isothermal curing of the resins was done at 300°C for 1 h in an air atmosphere. These cured resins were stable to 350 ± 30°C and decomposed in a single step above this temperature. The char yield of the resins increased on curing and was in the range 34-70%.

We herein report the preparation and properties of the first polymer blend using pyrene functionalized polyaniline (pf-PANI). The pf-PANI has been synthesized and its blend has been prepared with the copolymer of vinylidene fluoride and hexafluoropropylene P(VDF-HFP). The FTIR results reveal intermolecular interaction between the polar amide group of pf-PANI and the polarized CH2 group of P(VDF-HFP). The crystalline phase of PVDF of the copolymer revealed a transformation from α to β crystalline form after blending with pf-PANI, as found from FTIR and XRD measurements. The calorimetric measurements together with DMA results revealed the blend is partially miscible. The SEM measurements showed that the pf-PANI has been dispersed uniformly in the P(VDF-HFP) matrix. The solution photoluminescence spectrum of the pf-PANI exhibited emission in the purple–blue region and is slightly red shifted for the blend. The possible applications of this flexible fluorescent pf-PANI/P(VDF-HFP) has been suggested. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40162.

Hybrid composites based on isophthalate polyester and vinyl ester resin were fabricated with glass and bamboo fibers. 25, 50, and 75 wt % of glass fibers were replaced by bamboo fibers of the optimized glass fiber reinforced composites and were subjected to dynamical mechanical analysis to determine the dynamic properties as a function of temperature and frequency. The storage modulus E′ was found to decrease with the increase of weight fraction of bamboo fibers. Loss modulus was also found to decrease with loading while the damping property was found to increase marginally. Scanning electron micrographs of flexural fracture surfaces of composites demonstrated fiber-matrix bonding. Cole–Cole analysis was made to understand the phase behavior of the composite samples. Kubat parameter was calculated to study the adhesion between matrix and fibers of the fabricated composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Novel flexible polyurethane (PU) composite films containing nano-barium hexaferrite (BaF) and nano-barium titanate (BT) have been synthesized and characterized. The PU nanocomposites were synthesized from fullerenol and prepolymer of hexamethylene diisocyante and polytetramethylene glycol by adding 1–3% each of BaF (high permeability) and BT (high permittivity). The incorporation of the nanopowders was confirmed by X-ray diffraction (XRD), transmission electron microscopy, and energy dispersive X-ray diffraction (EDX). Study of thermal properties by thermogravimetric analysis and dynamic mechanical analysis revealed enhanced thermal stability of the nanocomposites. Study of mechanical properties showed that the tensile strength had increased remarkably in the nanocomposites. The electromagnetic-absorbing properties were studied by measuring the complex permeability and permittivity in the frequency range of 8.2 to 12.4 GHz. The good reflection loss of the nanocomposites at such low filler content suggests its potential applicability as a radar absorber. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The synthesis and characterization of several methyl nadimides endcapped resins based on tris (3-aminophenyl) phosphine oxide are described. These resins were prepared by reacting methyl nadic anhydride, pyromellitic dianhydride/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride/2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and tris(3-aminophenyl) phosphine oxide (TAP) in glacial acetic acid/acetone. Structural characterization of the resins was done by elemental analysis, IR, and 1 H-NMR. Thermal characterization of uncured resins using DSC and TGA techniques revealed an exothermic transition accompanied by a weight loss in the temperature range of 200-350°C

A terpolymer resin was synthesized by the condensation of 2,2′-dihydroxybiphenyl with guanidine and formaldehyde in the presence of 2M HCl as a catalyst. The resin obtained was characterized on the basis of elemental analysis, infrared spectroscopy, NMR spectroscopy, ultraviolet–visible spectroscopy, and thermogravimetric analysis/differential thermal analysis. The number-average molecular weight was determined by nonaqueous conductometric titration. A thermal study of the resin was carried out to determine its mode of decomposition, activation energy, order of reaction, frequency factor, entropy change, free energy, and apparent entropy change. The Freeman–Carroll and Sharp–Wentworth methods were applied for the calculation of the kinetic parameters, and the data from the Freeman–Carroll method were used to determine various thermodynamic parameters. The chelation ion-exchange properties of this resin were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+, and Pb2+ ions. A batch equilibrium method was used in the study of the selectivity of the metal-ion uptake that involved the measurements of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymer showed a higher selectivity for Fe3+ ions than for the other metal ions in this study. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010