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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

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

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 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

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

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