Journal of Polymers http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Thermal Stability and Kinetic Study of Isotactic Polypropylene/Algerian Bentonite Nanocomposites Prepared via Melt Blending Wed, 16 Apr 2014 12:33:20 +0000 http://www.hindawi.com/journals/jpol/2014/426470/ Isotactic polypropylene (iPP)/bentonite nanocomposites were prepared via melt blending using bentonite clay originated from Maghnia (Algeria). This clay was, at a first stage, used in its pure form (PBT) and then organically modified by Hexadecyl ammonium chloride (OBT). The effect of Maghnia bentonite dispersion on the iPP matrix was investigated by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). DSC results evidenced that unmodified or organomodified bentonite can act as a nucleating agent increasing the rate of crystallites formation. Moreover, a thermogravimetry analysis confirmed a significant enhanced thermal stability of IPP/clay nanocomposites compared to pure IPP. The Flynn-Wall-Ozawa and Tang methods were applied to determine the activation energy of the degradation process. The apparent activation energy   of thermal degradation for IPP/clay nanocomposites was much higher than that of virgin iPP. Comparatively to PBT, results indicate that OBT has an important effect on pure iPP thermal stability. Tensile modulus, tensile strength, and elongation at break were also measured and compared with those of pure iPP. Fayçal Benhacine, Farida Yahiaoui, and Assia Siham Hadj-Hamou Copyright © 2014 Fayçal Benhacine et al. All rights reserved. Thermal Degradation Studies of Terpolymer Derived from 2-Aminothiophenol, Hexamethylenediamine, and Formaldehyde Mon, 14 Apr 2014 11:36:23 +0000 http://www.hindawi.com/journals/jpol/2014/350832/ Terpolymer (2-ATPHMDAF-I) has been synthesized by the condensation of 2-aminothiophenol and hexamethylenediamine with formaldehyde in the presence of 2 M hydrochloric acid as a catalyst with 1 : 1 : 2 molar proportion of reacting monomers. The structure of newly synthesized terpolymer has been elucidated and confirmed on the basis of elemental analysis and various spectral techniques, that is, UV-visible, FT-IR, and 1H-NMR spectroscopy. Number average molecular weight () has been determined by conductometric titration in nonaqueous medium. The viscosity measurements in dimethyl sulfoxide (DMSO) have been carried out to ascertain the characteristic functions and constants. The studies have been further extended to nonisothermal thermogravimetric analysis for determination of their mode of decomposition and relative thermal stability. Activation energy , order of reaction , and frequency factor were calculated by Friedman, Chang, Sharp-Wentworth and Freeman-Carroll methods. Activation energy calculated by Friedman and Chang methods are in close agreement with each other while the results obtained from Freeman-Carroll and Sharp-Wentworth’s methods are found to be in a similar order. P. U. Belsare, A. B. Zade, P. P. Kalbende, and M. S. Dhore Copyright © 2014 P. U. Belsare et al. All rights reserved. Studies on Structural and Conducting Properties of Goethite Nanoparticles Doped HPMC Polymer Films Tue, 08 Apr 2014 09:10:32 +0000 http://www.hindawi.com/journals/jpol/2014/201464/ We have carried out systematic studies on Goethite nanoparticles doped (dispersed) HPMC polymer films to quantify the changes in their structural properties, the conductivity, and IR absorbance of films. It is observed that the addition of nanoparticles has significant influence on changing structural parameters and hence enhancing the conductivity of the polymer composite considerably. These polymer composites are water soluble. Thejas Gopal Krishne Urs, Mahadevaiah Dasaiah, and Rudrappa Somashekar Copyright © 2014 Thejas Gopal Krishne Urs et al. All rights reserved. Synthesis and Characterization of Polyesteramide Hot Melt Adhesive from Low Purity Dimer Acid, Ethylenediamine, and Ethanolamine Mon, 07 Apr 2014 11:49:24 +0000 http://www.hindawi.com/journals/jpol/2014/645832/ Polyesteramide hot melt adhesive (HMA) was synthesized using low purity dimer acid (composition: 3% linoleic acid, 75% dimer acid, and 22% trimer acid), ethanolamine, and ethylenediamine. Ethanolamine was added as a partial replacement (10, 20, and 30%) of ethylenediamine. Prepared HMAs were characterized for acid value, amine value, hydroxyl value, Fourier transform infrared spectroscopy, mechanical (tensile strength, percentage strain at brea, and shore D hardness), thermal (glass transition temperature, melting temperature, enthalpy of melting, crystallization temperature, and enthalpy of crystallization), rheological (viscosity versus shear rate and viscosity versus time), and adhesion properties (T-peel strength and lap shear strength). Replacement of ethylenediamine by ethanolamine replaced certain amide linkages by ester linkages, decreasing the intermolecular hydrogen bonding, leading to decrease in the crystallinity of the material, and thus the mechanical, thermal, adhesion, and rheological properties. However, HMAs prepared using ethanolamine will have better low temperature flexibility due to low glass transition temperature and better adhesion process due to the lower viscosity. Pravin G. Kadam, Parth Vaidya, and Shashank T. Mhaske Copyright © 2014 Pravin G. Kadam et al. All rights reserved. Characterization by Confocal Laser Scanning Microscopy of the Phase Composition at Interfaces in Thick Films of Polymer Blends Sun, 30 Mar 2014 07:32:40 +0000 http://www.hindawi.com/journals/jpol/2014/541248/ Confocal Laser Scanning Microscopy (CLSM) has been used as a fast, user-friendly, and noninvasive tool for characterizing the phase composition differences at the substrate and air interfaces in thick films of polymer blends. A clearly different phase composition at the blend/glass interface and at the blend/air interface has been detected. We show that PCBM preferentially accumulates at the glass/blend interface, while P3HT preferentially accumulates at the blend/air interface, by comparing the integrated signal intensity of the luminescence coming from both interfaces. Our results demonstrate that CLSM can be used conveniently for the fast identification of a preferential phase segregation at interfaces in polymer blends. This is useful in the research field on devices (like sensors or planar waveguides) that are based on very thick layers (thickness higher than 1 μm). Sandro Lattante, Andrea Perulli, and Marco Anni Copyright © 2014 Sandro Lattante et al. All rights reserved. Synthesis, Characterization, and Biodegradation Studies of Poly(1,4-cyclohexanedimethylene-adipate-carbonate)s Tue, 25 Mar 2014 11:48:45 +0000 http://www.hindawi.com/journals/jpol/2014/547325/ Aliphatic/alicyclic poly(1,4-cyclohexanedimethylene-adipate-carbonate)s (PCACs) were synthesized by a transesterification from 1,4-cyclohexamethylendimethanol (1,4-CHDM), adipic acid (AA), diethyl carbonate (DEC), and titanium butoxide Ti(OBu)4 as a transesterification catalyst. The synthesized PCACs were characterized by the Fourier transform infrared (FTIR), X-ray diffraction analysis (XRD), solubility, solution viscosity, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) for their structural, physical, thermal, and morphological investigation. The structure of synthesized PCACs was confirmed by FTIR. All TGA curves of PCACs shows 10% weight loss above 270°C, and they reveal good thermal stability. Biodegradability of PCACs was investigated by hydrolytic degradation at (pH 7.2 and 11.5), enzymatic degradation using Rhizopus delemar lips at 37°C in phosphate buffer solution (PBS), and soil burial degradation at 30°C. The hydrolytic degradation shows the greater rate of weight loss in PBS at pH-11.5 than pH-7.2. The hydrolytic and soil burial degradation shows faster rate of weight loss as compared to enzymatic degradation. Biodegradation rate of PCACs follows the order: PCAC-20 > PCAC-40 > PCAC-60. SEM images show that degradation occurred all over the film surface, creating holes and cracks. These biodegradable PCACs may be able to replace conventional polymer in the fabrication of packaging film in near future. Ajay S. Chandure, Ganesh S. Bhusari, and Suresh S. Umare Copyright © 2014 Ajay S. Chandure et al. All rights reserved. Optimization of Variables for Aqueous Extraction of Gum from Grewia mollis Powder Sun, 23 Mar 2014 12:26:58 +0000 http://www.hindawi.com/journals/jpol/2014/926850/ Grewia gum is a polysaccharide derived from the inner stem bark of the edible plant Grewia mollis. Juss (family Tiliaceae). It is a savanna shrub that grows wildly but is usually cultivated in Nigeria and Northern part of Cameroon. The main goal of the present study was to investigate the effect of aqueous extraction conditions on the extraction yield and physicochemical properties of the Grewia mollis. The studied aqueous extraction variables were water/powder (W/P) ratio (10 : 1–80 : 1 w/p), temperature (25.0–85.0∘C), time (1–3 h), and pH (4.0–10.0). The results indicated that the aqueous extraction variables exhibited the least significant () effect on the yield and the viscosity of the gum. The result shows that the ratio of extraction is the main factor affecting the extraction of gum. The optimized extraction condition for higher viscosity was at the powder/water ratio of 1 : 55.4, pH of 7, time of 1 h, and temperature of 50∘C. However, the optimized extraction condition for higher yield was at the powder/water ratio of 1 : 80, pH of 4, time of 3 h, and temperature of . Emmanuel Panyoo Akdowa, Thaddee Boudjeko, Alice Louise Woguia, Nicolas Njintang-Yanou, Claire Gaiani, Joel Scher, and Carl Moses F. Mbofung Copyright © 2014 Emmanuel Panyoo Akdowa et al. All rights reserved. Effect of Acetylation on Stability to Retrogradation of Starch Extracted from Wild Polynesian Arrowroot (Tacca leontopetaloides (L.) Kuntze) for Utilization as Adhesive on Paper Thu, 13 Mar 2014 12:41:11 +0000 http://www.hindawi.com/journals/jpol/2014/732174/ Starch was isolated from T. leontopetaloides tubers, chemically modified by acetylation with varying amounts of acetic anhydride. Monolayer of the ten acetylated and control starch powders was exposed on roof top for five weeks and pastes of both exposed and unexposed (control) samples were prepared with distilled water (1 : 3 w/w). The effects of acetylation, degree of substitution (DS), and exposure to sunlight were investigated to evaluate the retrogradation tendency of the adhesive pastes from changes in syneresis, tack strength, optical clarity, viscosity, gelation time, and drying time. The results obtained showed that all the adhesive properties studied were affected by both DS and exposure to sunlight. While tack strength, viscosity, and drying time were found to increase with increase in DS, syneresis, optical clarity, and gelation time were found to decrease with increase in DS. Increase in tack strength and reduction in syneresis imply that the acetylation treatment has made T. leontopetaloides starch more suitable for use in remoistenable adhesive applications. The reduction in syneresis, optical clarity, and gelation time with increase in DS was attributed to the strengthening of the bonds between the amylose and amylopectin molecules, preventing water leaching out of the starch granules. Hamza Abba, Abdulqadir Ibrahim, Gideon A. Shallangwa, Sani Uba, and Yakubu A. Dallatu Copyright © 2014 Hamza Abba et al. All rights reserved. Amphiphilic Fluorescent Well-Defined Living Polymer from Indole-3-Carboxaldehyde and 4-Bromo-1, 8-Naphthalic Anhydride: Synthesis and Characterization Mon, 10 Mar 2014 13:06:56 +0000 http://www.hindawi.com/journals/jpol/2014/325930/ We reported a well-defined amphiphilic fluorescent polymer bearing indole repeating units with naphthalimide pendants obtained by ATRP followed by chemical modification. The obtained polymer poly (N-allyl indole-2-(4-hydroxybutyl)-1, 8-naphthalimide) (PAIHN) was characterized by 1H NMR, FTIR, and GPC. The polymer showed a specific fluorescence emission maximum at 538 nm excited at 435 nm in aqueous solution. The amphiphilic nature of the polymer was investigated in aqueous solution using two spectroscopic methods, namely, absorption and emission spectroscopy. The Critical Miceller Concentration values obtained by UV-visible and fluorescence are in good agreement with each other. The micelles were characterized by TEM at concentration of 0.014 mg/mL. The polymer PAIHN prepared after tweaking exhibits green fluorescence at 538 nm due to the significant effect of naphthalimide moieties, whereas before tweaking the polymer poly (1-allyl indole-3-carbaldehyde) (PAIC) exhibits blue fluorescence at 425 nm due to indole repeating units of the polymer. Ambika Srivastava, Pooja Singh, Arti Srivastava, and Rajesh Kumar Copyright © 2014 Ambika Srivastava et al. All rights reserved. Preparation and Characterization of Talc Filled Thermoplastic Polyurethane/Polypropylene Blends Mon, 03 Mar 2014 12:31:56 +0000 http://www.hindawi.com/journals/jpol/2014/289283/ The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends. Emi Govorčin Bajsić, Vesna Rek, and Ivana Ćosić Copyright © 2014 Emi Govorčin Bajsić et al. All rights reserved. Synthesis, Characterization, and Electrical Properties of Poly(azophenyleneazo-2,4-diamino-1,5-phenylenes) Sun, 23 Feb 2014 09:13:52 +0000 http://www.hindawi.com/journals/jpol/2014/594841/ Poly(azophenyleneazo-2,4-diamino-1,5-phenylenes) were synthesized via diazotization of m- and p-phenylenediamine and azocoupling with m-phenylenediamine. It is found that, simultaneously, dihydrobenztriazolic units were formed as a result of cyclization reaction between amino and azo groups located in ortho position to each other. Oxidation of poly(azo-p-phenyleneazo-2,4-diamino-1,5-phenylene) was carried out and new polymer with benzotriazolic units in the main polymer chain was obtained. The conductivities of obtained polymers doped with iodine were increased with doping levels increase from 10−9–5 × 10−8 S/m to 0,1–0,6 S/m. A. H. Durgaryan, R. H. Arakelyan, N. A. Durgaran, and E. E. Matinyan Copyright © 2014 A. H. Durgaryan et al. All rights reserved. Microstructural and Mechanical Studies of PVA Doped with ZnO and WO3 Composites Films Tue, 21 Jan 2014 13:54:58 +0000 http://www.hindawi.com/journals/jpol/2014/846140/ Polymer composites of ZnO and WO3 nanoparticles doped polyvinyl alcohol (PVA) matrix have been prepared using solvent casting method. The microstructural properties of prepared films were studied using FTIR, XRD, SEM, and EDAX techniques. In the doped PVA, many irregular shifts in the FTIR spectra have been observed and these shifts in bands can be understood on the basis of intra/intermolecular hydrogen bonding with the adjacent OH group of PVA. The chemical composition, phase homogeneity, and morphology of the polymer composites of the polymer film were studied using EDAX and SEM. These data indicate that the distribution of nanosized ZnO and WO3 dopants is uniform and confirm the presence of ZnO and WO3 in the film. The crystal structure and crystallinity of polymer composites were studied by XRD. It was found that the change in structural repositioning and crystallinity of the composites takes place due to the interaction of dopants and also due to complex formation. The mechanical studies of doped polymer films were carried out using universal testing machine (UTM) at room temperature, indicating that the addition of the ZnO and WO3 with weight percentage concentration equal to 14% increases the tensile strength and Young’s modulus. N. B. Rithin Kumar, Vincent Crasta, Rajashekar F. Bhajantri, and B. M. Praveen Copyright © 2014 N. B. Rithin Kumar et al. All rights reserved. Poly Meta-Aminophenol: Chemical Synthesis, Characterization and Ac Impedance Study Sun, 19 Jan 2014 12:26:44 +0000 http://www.hindawi.com/journals/jpol/2014/827043/ The present work is an investigation of AC impedance behaviour of poly(meta-aminophenol). The polymer was prepared by oxidative chemical polymerization of meta-aminophenol in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymer was characterized by GPC, Elemental analysis, UV-VIS-NIR, FT-IR, 1H NMR, XRD, SEM, and TGA-DTA. The AC conductivity and dielectric response were measured at a temperature range from 303 to 383 K in the frequency range of 20 Hz to 106 Hz. The AC conductivity data could be described by the relation , where the parameter “” and values decrease in the entire range of study and hence follow Correlated Barrier Hopping conduction mechanism. Both dielectric constant and dielectric loss increase with the decrease of frequency exhibiting strong interfacial polarization at low frequency and the dissipation factor also decreases with frequency. Complex electric modulus and dissipation factor exhibit two relaxation peaks, indicating two-phase structure as indicated by a bimodal distribution of relaxation process. The activation energies corresponding to these two relaxation processes were found to be 0.07 and 0.1 eV. Thenmozhi Gopalasamy, Mohanraj Gopalswamy, Madhusudhana Gopichand, and Jayasanthi Raj Copyright © 2014 Thenmozhi Gopalasamy et al. All rights reserved. Role of Hard-Acid/Hard-Base Interaction on Structural and Dielectric Behavior of Solid Polymer Electrolytes Based on Chitosan-XCF3SO3 (X = Li+, Na+, Ag+) Thu, 16 Jan 2014 09:58:09 +0000 http://www.hindawi.com/journals/jpol/2014/906780/ Solid films of pure chitosan, chitosan-LiCF3SO3, chitosan-NaCF3SO3, and chitosan-AgCF3SO3 were prepared using solution cast technique. The influence of cation size on the chitosan structure has been investigated by X-ray diffraction technique. The interaction between the alkali metal ions and the donor atoms of chitosan polymer is a strong hard-acid/hard-base interaction. It was found that the intensity of crystalline peaks of chitosan decreases with increase of cation size. The impedance analysis shows that ionic transport is high for the high amorphous system. The second semicircle in - plots and the surface plasmonic resonance (SPR) peaks in chitosan-AgCF3SO3 sample system reveal the formations of silver metal nanoparticles. It was found that the high amorphous sample exhibits the high dielectric constant and dielectric loss values. The increase of dielectric constant and dielectric loss with temperature for chitosan-salt membranes indicated an increase of charge carrier concentration. Shujahadeen B. Aziz and Zul Hazrin Z. Abidin Copyright © 2014 Shujahadeen B. Aziz and Zul Hazrin Z. Abidin. All rights reserved. Adsorption of Chromium(VI) from Aqueous Solutions by Coffee Polyphenol-Formaldehyde/Acetaldehyde Resins Thu, 26 Dec 2013 14:25:08 +0000 http://www.hindawi.com/journals/jpol/2013/798368/ Removal of chromium(VI) from wastewater is essential as it is toxic. Thus, removal of chromium(VI) was performed using coffee polyphenol-formaldehyde/acetaldehyde resins as adsorbents. Adsorbent resins were prepared by condensation of decaffeinated coffee powder with formaldehyde/acetaldehyde and used for the removal of Cr(VI) ions from aqueous solutions. A simple and sensitive solid phase extraction procedure was applied for the determination of chromium at trace levels by spectroscopic method using 1,5-diphenylcarbazide reagent. The adsorption of Cr(VI) on the coffee polyphenol-formaldehyde/acetaldehyde resins was monitored by FTIR and EDX analysis. The metal adsorption parameters such as contact time, pH, Cr(VI) ion concentration, and adsorbent dose were investigated. For Cr(VI), the maximum adsorption capacity of coffee polyphenol-formaldehyde resins was 98% at pH 2. The experimental results showed that Cr(VI) bound strongly with coffee polyphenol-formaldehyde/acetaldehyde resins and utilization of resins could be improved greatly by reuse. Khudbudin Mulani, Siona Daniels, Kishor Rajdeo, Sanjeev Tambe, and Nayaku Chavan Copyright © 2013 Khudbudin Mulani et al. All rights reserved. Structure/Property Relationships of Poly(L-lactic Acid)/Mesoporous Silica Nanocomposites Tue, 24 Dec 2013 08:59:46 +0000 http://www.hindawi.com/journals/jpol/2013/162603/ Biodegradable poly(L-lactic acid) (PLLA)/mesoporous silica nanocomposites were prepared by grafting L-lactic acid oligomer onto silanol groups at the surface of mesoporous silica (SBA-15). The infrared results showed that the lactic acid oligomer was grafted onto the mesoporous silica. Surface characterization of mesoporous silica proved that the grafted oligomer blocked the entry of nitrogen into the mesopores. Thermal analysis measurements showed evidence that, once mixed with PLLA, SBA-15 not only nucleated the PLLA but also increased the total amount of crystallinity. Neat PLLA and its nanocomposites crystallized in the same crystal habit and, as expected, PLLA had a defined periodicity compared with the nanocomposites. This was because the grafted macromolecules on silica tended to cover the lamellar crystalline order. The g-SBA-15 nanoparticles improved the tensile moduli, increasing also the tensile strength of the resultant nanocomposites. Overall, the silica concentration tended to form a brittle material. Javier Gudiño-Rivera, Francisco J. Medellín-Rodríguez, Carlos Ávila-Orta, Alma G. Palestino-Escobedo, and Saúl Sánchez-Valdés Copyright © 2013 Javier Gudiño-Rivera et al. All rights reserved. Creep and Recovery Behavior of Compression Molded Low Density Polyethylene/Cellulose Composites Wed, 18 Dec 2013 10:12:17 +0000 http://www.hindawi.com/journals/jpol/2013/209529/ Low density polyethylene (LDPE) is an important industrial material because it is durable, light-weight, easily processed and characteristically inert, but its everyday use is hazardous to the environment. The solution to this seems to consist of incorporation of biopolymers in the structure of LDPE to form composites. Compression molded composites at different cellulose loading were subjected to creep tests at 30, 40, 50, and 60°C. The samples were displaced for 12 minutes and allowed to recover for 12 minutes. Creep behavior of the polymer composites was governed by temperature, time, and cellulose loading. Creep performance decreased with increase in temperature and improved with cellulose loading while creep modulus decreased with increase in time and temperature. Time temperature superposition was used to predict the long time (up to 106 s) creep behavior of the samples. William-Landel-Ferry (WLF) model offered a better description of the shift factors based on the short term data that was used to predict the long time behavior of the polymer composites by shifting the curves along the logarithmic time axis. The deformation was dependent on free volume. Martin M. Riara, Abdallah S. Merenga, and Charles M. Migwi Copyright © 2013 Martin M. Riara et al. All rights reserved. Optimization of Cultural Conditions for Production of Extracellular Polymeric Substances (EPS) by Serpentine Rhizobacterium Cupriavidus pauculus KPS 201 Mon, 09 Dec 2013 10:16:21 +0000 http://www.hindawi.com/journals/jpol/2013/692374/ Extracellular polymeric substances (EPS) are complex biopolymers produced by a wide array of microorganisms for protection against dessication, aggregation, adhesion, and expression of virulence. Growth associated production of EPS by Ni-resistant Cupriavidus pauculus KPS 201 was determined in batch culture using sodium gluconate as the sole carbon source. The optimum pH and temperature for EPS production were 6.5 and 25°C, respectively. Optimal EPS yield (118 μg/mL) was attained at 0.35% Na-gluconate after 72 h of growth. Cupriavidus KPS 201 cells also utilized glutamate, acetate, pyruvate, fumarate, malate, malonate, formate, citrate, and succinate for EPS production. Although EPS production was positively influenced by the increase of nitrogen and phosphate in the growth medium, it was negatively influenced by nickel ions. Compositional analysis of the purified EPS showed that it is a homopolymer of rhamnose containing uronic acid, protein, and nucleic acid. Presence of lipids was also detected with spectroscopy. Non-destructive EPS mediated biofilm formation of KPS 201 was also visualized by epifluorescence microscopy. Arundhati Pal and A. K. Paul Copyright © 2013 Arundhati Pal and A. K. Paul. All rights reserved. Porous and Cross-Linked Cellulose Beads for Toxic Metal Ion Removal: Hg(II) Ions Thu, 28 Nov 2013 16:05:41 +0000 http://www.hindawi.com/journals/jpol/2013/309136/ Mercury is a highly toxic and hazardous pollutant even in trace quantity which poses a major threat to the ecosystem on deposition in the environment. Removal of mercury from aqueous systems has been a subject of immense interest for researchers. The synthesis of highly cross-linked cellulose beads embedded with ferric oxide for removal of Hg(II) ions from aqueous systems has been investigated. The beads were synthesized by solution polymerization technique. The impact of solution pH, ferric oxide content, and initial concentration of Hg(II) ions on the uptake of Hg(II) ions revealed that maximum adsorption occurs at pH 6.0 with beads having 10 wt% Fe2O3 content. Equilibrium adsorption of Hg(II) ions followed the Langmuir isotherm model. Adsorption was observed to follow pseudo second-order kinetic model and intraparticle diffusion model. Renuka R. Gonte, K. Balasubramanian, and Jyothi D. Mumbrekar Copyright © 2013 Renuka R. Gonte et al. All rights reserved. Effects of Polarity on the Filler-Rubber Interaction and Properties of Silica Filled Grafted Natural Rubber Composites Sun, 27 Oct 2013 17:45:37 +0000 http://www.hindawi.com/journals/jpol/2013/279529/ The grafting of an olefinic monomer like acrylonitrile (AN), methyl methacrylate (MMA), and styrene (ST) onto natural rubber (NR) was carried out to enhance the polarity of the new chemical groups on the NR backbone and, in turn, to improve the filler-rubber interaction. The grafted natural rubber (GNR) produced was compounded and then vulcanization was carried out in the presence of silica as a reinforcing filler. The physical properties and aging resistance provided by the presence of the polar functional groups of the GNR composites were investigated and compared with other rubbers such as SBR, NBR, and NR. The GNRs provided significant improvements in resistance of the composites to thermal, oil, and ozone while maintaining the mechanical properties of the rubber. Therefore, these properties can be controlled as a function of the polarity of functional groups on the NR backbone. Morphological studies confirmed a shift from ductility failure to brittle with the presence of the polar group on the rubber chains. Wanvimon Arayapranee and Garry L. Rempel Copyright © 2013 Wanvimon Arayapranee and Garry L. Rempel. All rights reserved. Phototrophic Growth and Accumulation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Purple Nonsulfur Bacterium Rhodopseudomonas palustris SP5212 Mon, 21 Oct 2013 08:56:58 +0000 http://www.hindawi.com/journals/jpol/2013/523941/ The ability of the phototrophic bacterium Rhodopseudomonas palustris SP5212 to produce polyhydroxyalkanoates (PHAs), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] in particular was, assessed in acetate medium supplemented with hydroxybutyrate and valerate as cosubstrates. The isolate accumulated the polymer accounting for some 49.06% and 30% of cell dry weight when grown in hydroxybutyrate and valerate, respectively. PHA accumulation as well as 3HV monomer incorporation (30 mol%) was maximum at 0.1% hydroxybutyrate, while valerate at 0.1% and 0.3% was suitable for total polymer accumulation and 3HV monomer incorporation, respectively. Cosupplementation of hydroxybutyrate and valerate in the ratio of 3 : 1 led to the accumulation of PHA accounting for 54% of cell dry weight, which contained more than 50 mol% of 3HV monomer. Moreover, the biphasic cultivation conditions with hydroxybutyrate as cosubstrate have improved the quality as well as quantity of the accumulated copolymer significantly. M. Mukhopadhyay, A. Patra, and A. K. Paul Copyright © 2013 M. Mukhopadhyay et al. All rights reserved. Studies on Ion-Exchange Properties of Polyaniline Zr(IV) Tungstoiodophosphate Nanocomposite Ion Exchanger Mon, 07 Oct 2013 08:33:38 +0000 http://www.hindawi.com/journals/jpol/2013/356058/ Organic-inorganic hybrid materials prepared by sol-gel approach have attracted a great deal of attention in material science. Organic polymeric part of the composite provides mechanical and chemical stability whereas the inorganic part supports the ion-exchange behaviour and thermal stability and also increases the electrical conductivity. Such modified composite materials can be applied as an electrochemically switchable ion exchanger for water treatment, especially water softening. Polyaniline zirconium(IV) tungstoiodophosphate nanocomposite ion exchanger is prepared by sol-gel method. Polyaniline zirconium(IV) tungstoiodophosphate nanocomposite ion exchanger is synthesized and characterized by Fourier transform-infrared spectra, ultraviolet-visible spectra, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, ion exchange, conductivity, and antimicrobial studies. A mechanism for the formation of the polyaniline zirconium(IV) tungstoiodophosphate nanocomposite ion exchanger was discussed. The route reported here may be used for the preparation of other nanocomposite ion exchangers. K. Jacinth Mispa, P. Subramaniam, and R. Murugesan Copyright © 2013 K. Jacinth Mispa et al. All rights reserved. Rheological Properties and Reverse Micelles Conditions of PEO-PPO-PEO Pluronic F68: Effects of Temperature and Solvent Mixtures Sat, 28 Sep 2013 11:31:08 +0000 http://www.hindawi.com/journals/jpol/2013/768653/ The rheological properties of Pluronic F68 were dissolved in various water/organic liquid mixtures over a wide range of temperatures, all at a concentration of 20 mg/mL. We have considered the following binary mixtures: Pluronic F68/water, F68/p-xylene, and F68/phenol. Various conformational transitions were detected and interpreted. We have also shown that these mixtures retain a Newtonian behavior independently of temperature and conformational changes. For ternary F68/p-xylene/water, F68/phenol/water, and F68/water/phenol mixtures, the behaviour of the solution is intimately related to the temperature and the amount of water and organic solvent added. Mouna Ben Henda, Naoufel Ghaouar, and Abdelhafidh Gharbi Copyright © 2013 Mouna Ben Henda et al. All rights reserved. Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles and Utilization to Impart Antibacterial Finishing for Wool and Acrylic Fabrics Thu, 26 Sep 2013 08:58:42 +0000 http://www.hindawi.com/journals/jpol/2013/792035/ The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride/UV system is used in the synthesis of silver nanoparticles (AgNPs). Green synthesis method involved using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. AgNPs obtained had a spherical shape morphology and a size of 1–7 nm. To impart antibacterial properties, wool and acrylic fabrics were treated with AgNPs obtained. The PI/UV system was further utilized to fix AgNPs onto wool and acrylic fabrics by photocrosslinking to impart durable antibacterial properties. The effect of irradiation time on the antibacterial performance before and after repeated washing cycles was studied. S. aureus (as G +ve) and E. coli (as G −ve) were used to estimate the antibacterial performance of the finished fabrics. The antibacterial performance was directly proportional to the irradiation time but inversely proportional to the number of washing cycles. However, after the 15th washing cycle, samples still have bacteriostatic effect; that is, although they show zero inhibition zone, they cannot be attacked by the bacterial growth and do not inhibit the bacterial growth. AgNPs finished wool fabrics showed more antibacterial activity than those of AgNPs finished acrylic fabrics. M. A. El-Sheikh, L. K. El Gabry, and H. M. Ibrahim Copyright © 2013 M. A. El-Sheikh et al. All rights reserved. Structural, Dielectric, Optical and Magnetic Properties of Ti3+, Cr3+, and Fe3+: PVDF Polymer Films Tue, 24 Sep 2013 11:50:37 +0000 http://www.hindawi.com/journals/jpol/2013/295291/ Highly transparent and very clear nature of PVDF: Ti3+, PVDF: Cr3+, and PVDF: Fe3+ polymer films of good quality have been synthesized by employing solution casting method. XRD profiles have confirmed semicrystalline structures in -, -, and -PVDF phases. IR spectra have confirmed these findings and revealed some structural defects such as monofluorinated alkenes. Emission spectra reveal that PVDF: Ti3+ has a blue emission, PVDF: Cr3+ has blue emission, and PVDF: Fe3+  red emission was observed. The conductivity and dielectric measurements have also been carried out as function of frequency and temperature changes. Due to the presence of the transition metal ions in these films, significant improvement in the ionic conductivity has been noticed. The dielectric behaviors of these films have been analyzed using dielectric permittivity (), dissipation factor (tan ), and impedance spectra (Z1 and Z11). VSM measurements have confirmed that the PVDF: Ti3+ exhibits antiferromagnetic nature, PVDF: Cr3+ film ferromagnetic nature, and PVDF: Fe3+ film strong paramagnetic nature. Thus, the present study has successfully explored the fact that these optical materials are also potential enough in both conductivity and magnetic properties for their use in applications suitably. M. Obula Reddy and L. Raja Mohan Reddy Copyright © 2013 M. Obula Reddy and L. Raja Mohan Reddy. All rights reserved. Evaluation of Effect of Various Nanofillers on Technological Properties of NBR/NR Blend Vulcanized Using BIAT-CBS System Tue, 17 Sep 2013 10:54:29 +0000 http://www.hindawi.com/journals/jpol/2013/798232/ Owing to processing ease and resistance to oils and chemicals, NBR is widely used in many industries. But since neat NBR has only poor tensile properties, it is better to use suitable blends of NR and NBR after incorporating appropriate nanoingredients before vulcanization. It is well established that nanoparticles can be easily dispersed in a more uniform pattern in polymer matrix, thereby enhancing the technological properties of the elastomer vulcanizate. Since there are no systematic comparative studies on technological properties of NBR/NR blend containing different nanoingredients, efforts have been made in this study to investigate cure and technological properties like tensile properties, tear resistance, compression set, hardness, abrasion loss and swelling value of NBR/NR (80/20) blend vulcanizates containing stearic acid-coated nano-zinc oxide (ZOS), nano-BIAT, nano-silicate-coated CaCO3, PEO-coated calcium silicate, and surface-modified carbon nanotubes (CNT). XRD and electron microscopy have been used for morphological analysis. The nano ingredients were effective in enhancing the technological properties of the vulcanizates. Among the nanofillers, modified CNT was found to impart superior properties to NBR/NR blend due to more intercalation. Shaji P. Thomas, Saliney Thomas, C. V. Marykutty, and E. J. Mathew Copyright © 2013 Shaji P. Thomas et al. All rights reserved. Synthesis of Polyethers Containing Triazole Units in the Backbone by Click Chemistry in a Tricomponent Reaction Sat, 14 Sep 2013 12:41:32 +0000 http://www.hindawi.com/journals/jpol/2013/167106/ A series of linear aromatic polyethers containing triazole units were synthesized via the direct click reaction of dibromide and bisethynyl compounds in the presence of sodium azide as one pot reaction. The structures of polymers were approved by using IR and 1H NMR techniques. The solubility experiments showed that polymers have good solubility in polar aprotic solvents such as DMSO, DMF, and NMP at higher temperatures. Thermal stability of the polymers was measured using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) which indicated that they possessed good thermal stability ( up to 558°C) and high (191.7–260°C) under N2 atmosphere. All the polymers were amorphous according to the DSC and X-ray diffraction. These polymers exhibited strong UV-vis absorption maxima near to 400 nm and up to 500 nm in DMSO solution. Moslem Mansour Lakouraj, Vahid Hasantabar, and Nazanin Bagheri Copyright © 2013 Moslem Mansour Lakouraj et al. All rights reserved. A Preliminary Investigation of Ductility-Enhancement Mechanism through In Situ Nanofibrillation in Thermoplastic Matrix Composites Mon, 09 Sep 2013 13:21:37 +0000 http://www.hindawi.com/journals/jpol/2013/424015/ A preliminary investigation of interrelationships between tensile stress-strain characteristics and morphology evolution during deformation is conducted on a commercially available thermoplastic composite with a low-surface-energy nanofibrillating poly(tetrafluoroethylene) (PTFE) additive. In this class of composites, the deformation-associated nanofibrillation of the low-surface-energy additive has been hypothesized to provide an additional dissipation mechanism, thereby enhancing the ductility of the composite. This class of composites offers potential for automotive light weighting in exterior and interior body and fascia applications; it is therefore of interest to investigate processing-structure-property interrelationships in these materials. This study specifically probes the interrelationships between the plastic deformation within the matrix and the fibrillation of the low-surface-energy additive; tensile tests are carried out at two different temperatures which are chosen so as to facilitate and suppress plastic deformation within the matrix polymer. Based on these preliminary investigations, it is noted that PTFE fibrillation acts synergistically with the ductile deformation of the matrix resin resulting in higher strains to failure of the composite; the results also suggest that the mechanism of fibrillation-assisted enhancement of strains to failure may not operate in the absence of matrix plasticity. Bhaskar Patham and M. P. Poornendu Thejaswini Copyright © 2013 Bhaskar Patham and M. P. Poornendu Thejaswini. All rights reserved. Rheological and Mechanical Characterization of Renewable Resource Based High Molecular Weight PLA Nanocomposites Tue, 27 Aug 2013 08:16:10 +0000 http://www.hindawi.com/journals/jpol/2013/403467/ The present study discusses structural aspects of nanocomposites and the ability of layered nanosilicates to alter the flow behaviour of poly(lactic acid) (PLA) melts. In addition, dynamic and static mechanical properties of PLA nanocomposites prepared from melt mixing method have been also discussed. A comparative study of nanocomposite properties has been conducted using two different nanoclays, natural montmorillonite modified with alkyl ammonium surfactant (OMMT), and commercially available organosilicate, Cloisite 30B, as reinforcements within the PLA matrix. Since OMMT has undergone better intercalation within the matrix, the corresponding nanocomposite showed superior mechanical and rheological characteristics than its C30B counterpart. P. J. Jandas, S. Mohanty, and S. K. Nayak Copyright © 2013 P. J. Jandas et al. All rights reserved. Hydrogen Sorption onto Hypercrosslinked Polymer Decorated with Metal-Organic Framework Mon, 12 Aug 2013 17:49:55 +0000 http://www.hindawi.com/journals/jpol/2013/684584/ Metal-organic framework decorated styrene-maleic acid (SMA) co-polymer beads were synthesized by slow diffusion of TEA. The obtained materials were characterized by FTIR, scanning electron microscopy, and thermogravimetric analysis. The different dicarboxylic acid linkers influenced the crystal morphologies and hydrogen-storage behavior of the polymer beads. Hydrogen-storage measurements revealed slow micropore opening mechanism involved in adsorption of hydrogen. Renuka R. Gonte, P. C. Deb, and K. Balasubramanian Copyright © 2013 Renuka R. Gonte et al. All rights reserved.