ISRN Polymer Science The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Removal of Toxic Metal Ions from Water Using Chelating Terpolymer Resin as a Function of Different Concentration Time and pH Thu, 22 May 2014 08:03:28 +0000 Terpolymer resin 4-ASAUF was synthesized by the condensation of 4-aminosalicylic acid (4-ASA) and urea (U) with formaldehyde (F) in the presence of 2 N hydrochloric acid. The structure of the resin was characterized by various spectral techniques like infrared (FTIR) and nuclear magnetic resonance (1H and 13C-NMR) spectroscopy. The empirical formula and empirical weight of the resin were determined by elemental analysis. The physiochemical properties of terpolymer resin were determined. The morphological feature of the 4-ASAUF terpolymer resin was studied by scanning electron microscopy (SEM). The chelating ion-exchange property of this copolymer was studied for eight metal ions, namely, Fe3+, Cu2+, Ni2+, Co2+, Hg2+, Zn2+, Cd2+, and Pb2+ ions by using batch equilibrium method. The chelating ion-exchange study was carried out over a wide pH range at different time intervals using different electrolyte of various ionic strengths. Mangesh S. Dhore, Suraj S. Butoliya, and Anil B. Zade Copyright © 2014 Mangesh S. Dhore et al. All rights reserved. Synthesis and Characterization of New Organosoluble and Thermally Stable Poly(thioether-amide)s Bearing Pyridine Subunit in the Main Chain Sun, 27 Apr 2014 14:02:04 +0000 We report the synthesis of new polyamides containing 2,6-bis(2-thio-2-(4-carboxyphenyl)-1-oxo)pyridine subunit, under microwave irradiation using Yamasaki phosphorylation method. The solubility, thermal behavior, and viscosity of polyamides were evaluated. The structures of polymers have been characterized using IR and 1H NMR spectroscopy. These polyamides showed good solubility, viscosity, high thermal stability, and glass transition temperatures. Their viscosities and glass transition temperatures are in the range of 0.63–0.88 and 223–295°C, respectively. Thermal stabilities for 10% weight loss (T10) are 137–173°C and for 50% weight loss (T50) are in the range of 483–523°C. The study of surface morphology showed particle and amorphous structures. Esmael Rostami, Maryam Bagherzadeh, Tahereh Alinassab, Maryam Mohammadpour, Masume Zangooei, Mahmood Feraidooni, Fatemeh Tavazo, and Zahra Keshavarz Copyright © 2014 Esmael Rostami et al. All rights reserved. In Situ Disassembling Behavior of Composite Hydrogels for the Efficient Removal of Crystal Violet Dye from Aqueous Solution Wed, 12 Mar 2014 14:54:39 +0000 A novel method for the disassembly of synthetic hydrogels in situ and thereby enhanced adsorption of crystal violet dye is reported. Silicon present in the husk ashes of Panicum miliare is used as the trigger for disassembly of poly(2-acrylamido-1-propane sulfonic acid-co-itaconic acid) hydrogels. Disassembling ability of the ash was determined by changing the temperature of the husk ash. Surface area and particle sizes of both the disassembled and assembled forms of the hydrogels were determined by E. Suito’s method. Removal of crystal violet dye from aqueous solution and the respective adsorption capacities of disassembled and assembled forms of hydrogels were compared by varying parameters such as pH, temperature, and agitation speed. Concentration of the dye in aqueous solution was determined by using UV-Visible spectrophotometer. FTIR analysis was carried out for the characterization of the hydrogels, ash blended hydrogels, and the free ashes. SEM imaging was carried out to differentiate the surfaces of the assembled and disassembled hydrogels. Venkatesan Srinivasan, Sundaram Thiraviam, Kullagounder Subramani, Sibi Srinivasan, Pragathiswaran Chelliah, and Stanley Anthuvan Babu Copyright © 2014 Venkatesan Srinivasan et al. All rights reserved. The Manufacture of Hot-Compacted Layered Composite Systems Made of Oriented Semifinished PP-Films Tue, 04 Mar 2014 11:13:38 +0000 Monoaxial stretched PP-films are used for the manufacture of hot-compacted layered composites. These are layered with stretched co-extruded coupling agent films, and are consolidated to laminates by means of a hot-compaction process, which employs pressure and temperature. This paper aims to examine the influence of the process settings on the properties of the composites during the hot-compaction process. For this purpose, the mechanical values will be determined by means of tensile testing variously compacted and configured layered film composites. Björn Rohde, Andrea Wibbeke, Hans-Peter Heim, and Volker Schöppner Copyright © 2014 Björn Rohde et al. All rights reserved. Preparation and Drug-Release Kinetics of Porous Poly(L-lactic acid)/Rifampicin Blend Particles Sun, 23 Feb 2014 16:18:59 +0000 Porous polymer spheres are promising materials as carriers for controlled drug release. As a new drug-carrier material, blend particles composed of poly(L-lactic acid) (PLLA) and rifampicin were developed using the freeze-drying technique. The blend particles exhibit high porosity with a specific surface area of 10–40 m2 g−1. Both the size and porosity of the particles depend on the concentration of the original solution and on the method of freezing. With respect to the latter, we used the drop method (pouring the original solution dropwise into liquid nitrogen) and the spray method (freezing a mist of the original solution). The release kinetics of rifampicin from the blend particles into water depends significantly on the morphology of the blend particles. The results show that the release rate can be controlled to a great extent by tuning the size and porosity of the blend particles, both of which are varied by parameters such as the solution concentration and the method of freezing. Takashi Sasaki, Hiroaki Matsuura, and Kazuki Tanaka Copyright © 2014 Takashi Sasaki et al. All rights reserved. Damping Evaluation of Linseed Oil-Based Engineering Elastomers by Vibration Response Method Sun, 23 Feb 2014 13:44:35 +0000 A low cost experimental setup has been fabricated for evaluation of vibration damping properties of a variety of elastomers developed from linseed oil. Free and forced vibration principles were utilized in this experimental setup. Under forced vibration, the shear loss factor varies from 0.37 to 1.03 at 2nd bending vibration mode and 0.43 to 0.99 at 3rd bending vibration mode for different elastomers. The loss factor varies from 0.52 to 0.94 under free vibration. The loss factors determined by both forced and free vibration techniques are in good agreement with the loss factors obtained from dynamic mechanical analysis. The ultimate tensile strength and Young’s modulus of the elastomers vary from 0.37 to 3.71 MPa and 0.27 to 10.27 MPa, respectively, whereas these properties in compression are in the range of 3.1 to 72.9 MPa and 1.5 to 30.1 MPa, respectively. Thus, these elastomers are mechanically stable for vibration damping applications. Rakesh Das, Rajesh Kumar, and P. P. Kundu Copyright © 2014 Rakesh Das et al. All rights reserved. Synthesis of Carbon Nanotube Incorporated Molecular Imprinted Polymer with Binding Affinity towards Testosterone Wed, 19 Feb 2014 07:41:22 +0000 A novel polymer was synthesised using functionalized carbon nanotube and acrylamide as the polymer support for the separation of testosterone. The developed polymers were characterised using FT-IR, XRD, and SEM techniques. Imprinted polymer showed specificity towards the template testosterone. Among the various polymers, the MWCNT incorporated polymer showed high binding towards the used template. Investigation of the selectivity characteristics revealed that the developed polymer showed selectivity toward the template testosterone than similar compounds. The bound template could be totally recovered and regenerated polymer maintains its recognition property after repeated use. On the basis of the results, the imprinted polymer can be applied for the direct extraction of testosterone in clinical analysis. Anju Augustine and Beena Mathew Copyright © 2014 Anju Augustine and Beena Mathew. All rights reserved. Natural Rubber Latex: Study of a Novel Carrier for Casearia sylvestris Swartz Delivery Wed, 12 Feb 2014 07:12:43 +0000 Natural rubber latex (NRL) from Hevea brasiliensis has showed interesting biomedical properties as improving wound healing, cell adherence, tissue formation, and angiogenesis. It is used for biosynthesis of nanoparticles, sensors and prosthesis and for drug delivery systems (for drugs, plant extracts, and nanoparticles). To enhance its wound healing properties was incorporated Casearia sylvestris Swartz extract, whose pharmacological activity includes anti-inflammatory, analgesic, antiseptic, antiulcer, and antitumor due to its casearins and phenols. Results showed the prolonged release of its compounds (35 days) and the mechanism of release is super case II () by Korsmeyer-Peppas model. Although SEM shows different sizes of clusters at the surface, the release is homogeneous through the biomembrane. FTIR shows no interaction between the matrix and the extract, with computation of the presence of some casearins. Felipe Azevedo Borges, Luis Felipe Cesar Bolognesi, Alberto Trecco, Bruno de Camargo Drago, Larisa Baldo de Arruda, Paulo Noronha Lisboa Filho, Elaise Gonçalves Pierri, Carlos Frederico de Oliveira Graeff, André Gonzaga dos Santos, Matheus Carlos Romeiro Miranda, and Rondinelli Donizetti Herculano Copyright © 2014 Felipe Azevedo Borges et al. All rights reserved. Characterization of Some Spelt Wheat Starches as a Renewable Biopolymeric Material Wed, 05 Feb 2014 10:01:05 +0000 The aim of this work was to analyze selected physical, chemical, thermal, and rheological properties of starches isolated from different spelt wheat varieties. The analyzed starches contained from 22.5 to 24.6 g/100 g of amylose and from 45.9 to 50.6 mg/100 g of phosphorus. Ranges of characteristic gelatinization temperatures, , , and , were 55.7–58.5°C, 61.1–62.6°C, and 67.4–68.2°C, respectively, while gelatinization enthalpy ranged from 8.87 to 9.96 J/g. The pasting curves showed significant differences in pasting characteristics of the starches. The values of maximum viscosity () and viscosity after cooling () determined for the starch pastes were in the range of 82.3–100.7 B.U. and 149.3–172.7 B.U., respectively. The starch pastes demonstrated non-Newtonian, shear thinning flow behaviour and thixotropy phenomenon. After cooling the resulting starch gels were characterized by different viscoelastic properties, with a dominance of elastic features (). The starches exhibited different tendency to retrogradation, with its degree () in the range of 21.1–37.4%. Dorota Gałkowska, Teresa Witczak, Jarosław Korus, and Lesław Juszczak Copyright © 2014 Dorota Gałkowska et al. All rights reserved. Thermal Expansion Behavior of Nonoriented Polypropylene/Clay Composites Mon, 03 Feb 2014 06:11:26 +0000 Linear thermal expansion coefficient (LTEC) was measured for compression molding samples of polypropylene (PP)/clay composites with clay loading of 0 to 7 wt%. Composites were prepared by internal batch mixer and specimens were prepared by compression molding. These processing methods are not anticipated to have a preference for orientation; therefore effect of anisotropy was minimal. The LTEC was measured along three different faces of the compression molding sheets, parallel to compression direction S1 and perpendicular to compression directions S2 and S3. The LTEC for neat PP measured by current research,  mm/mm/°C, was not found to be altered by direction of the measurements. Similar behavior was observed with composites having very moderate clay content, that is, 5 wt%. An interesting finding by current study was that incorporating clay particles into the PP matrix led to better shrinkage or contraction behavior of the samples prepared by compression molding. Fares D. Alsewailem and Metin Tanoglu Copyright © 2014 Fares D. Alsewailem and Metin Tanoglu. All rights reserved. Polydimethylsiloxane and Castor Oil Comodified Waterborne Polyurethane Tue, 17 Dec 2013 10:07:36 +0000 In view of both improving properties of waterborne polyurethane (WPU) and sufficient utilization of renewable resources, a series of polydimethylsiloxane (PDMS) and castor oil (C.O.) comodified anionic WPUs with internal cross-linking was prepared through a prepolymer mixing process. The chemical structure of synthesized polymers was characterized by Fourier transforms infrared spectroscopy (FT-IR). In comparison with traditional linear WPU synthesized from petroleum-based polyols, these novel WPU films exhibited superior properties in solvent and water resistance, thermal stability, and mechanical strength, which suggest promising applications of these new environmentally friendly materials, particularly in the area of decorative and protective coatings. In addition, the results showed that with the increase in PDMS content in these co-modified WPUs the average particle size, the water resistance, and the thermal stability increased accordingly while the solvent resistance and the mechanical properties decreased. Xuan Ji, Yanming Zhou, Baoling Zhang, Caiying Hou, and Guozhang Ma Copyright © 2013 Xuan Ji et al. All rights reserved. The Addition of Graphene to Polymer Coatings for Improved Weathering Thu, 21 Nov 2013 14:18:58 +0000 Graphene nanoflakes in different weight percentages were added to polyurethane top coatings, and the coatings were evaluated relative to exposure to two different experimental conditions: one a QUV accelerated weathering cabinet, while the other a corrosion test carried out in a salt spray chamber. After the exposure tests, the surface morphology and chemical structure of the coatings were investigated via atomic force microscopy (AFM) and Fourier transform infrared (FTIR) imaging. Our results show that the addition of graphene does in fact improve the resistance of the coatings against ultraviolet (UV) degradation and corrosion. It is believed that this process will improve the properties of the polyurethane top coating used in many industries against environmental factors. Nurxat Nuraje, Shifath I. Khan, Heath Misak, and Ramazan Asmatulu Copyright © 2013 Nurxat Nuraje et al. All rights reserved. Mechanical Properties and Failure Topography of Banana Fiber PF Macrocomposites Fabricated by RTM and CM Techniques Mon, 19 Aug 2013 11:43:48 +0000 Banana fiber reinforced phenol formaldehyde composites with different fiber lengths and fiber loadings were prepared by compression molding (CM) and resin transfer molding (RTM) techniques. The mechanical properties such as tensile, flexural, and impact behavior were studied. RTM composites showed improved tensile and flexural properties as compared to CM composites. On the other hand, impact strength of RTM composites is slightly lower than that of CM composites. From the studies, it was found that mechanical properties increased with the increase in fiber loading, reached a plateau at 30–40 wt%, and then subsequently decreased with an increase in fiber loading in both techniques. At high fiber weight fractions, the strength decreased due to poor wetting and very poor stress transfer. The stress value increased up to 30 mm fiber lengths and then decreased. In order to examine the fracture surface morphology of the composites, scanning electron microscopy (SEM) was performed on the composite samples. A good relationship between morphological and mechanical properties has been observed. Finally, tensile strength of the composites fabricated by RTM and CM was compared with theoretical predictions. K. N. Indira, Jyotishkumar Parameswaranpillai, and Sabu Thomas Copyright © 2013 K. N. Indira et al. All rights reserved. Geopolymer Binders: A Need for Future Concrete Construction Tue, 30 Jul 2013 09:36:05 +0000 Applications of polymer based binder material can be an ideal choice in civil infrastructural applications since the conventional cement production is highly energy intensive. Moreover, it also consumes significant amount of natural resources for the large-scale production in order to meet the global infrastructure developments. On the other hand the usage of cement concrete is on the increase and necessitates looking for an alternative binder to make concrete. Geopolymer based cementitious binder was one of the recent research findings in the emerging technologies. The present study is aimed at providing a comprehensive review on the various production processes involved in the development of a geopolymer binder. More studies in the recent past showed a major thrust for wider applications of geopolymer binder towards a cost economic construction practice. This also envisages the reduction of global warming due to carbon dioxide emissions from cement plants. K. Srinivasan and A. Sivakumar Copyright © 2013 K. Srinivasan and A. Sivakumar. All rights reserved. Selective Cu(II) Adsorption from Aqueous Solutions Including Cu(II), Co(II), and Ni(II) by Modified Acrylic Acid Grafted PET Film Mon, 29 Jul 2013 13:13:35 +0000 Acrylic acid (AAc) grafted polyethylene terephthalate (PET) films were prepared by γ irradiation. The graft films showed little metal ion adsorption due to compact structure of the graft chains as shown by the scanning electron microscopy (SEM) images which restricted the access of metal ions to the functional groups. Therefore, the graft films were modified with KOH treatment for expansion of the graft chains to facilitate the access of metal ions to the functional groups. The modified films were used to study the selective Cu2+ adsorption from aqueous solution containing Cu2+, Co2+, and Ni2+. Langmuir and Freundlich isotherm models were used for interpretation of selective equilibrium adsorption data and Langmuir model showed better fitting with experimental data. Again pseudo-first-order and pseudo-second-order equations were used for interpretation of selective kinetic adsorption data and pseudo-second-order equation showed better prediction of experimental data. The adsorbent film showed high selectivity towards Cu2+ in presence of Cu2+, Co2+, and Ni2+ in the pH range of 1.5 to 4.5. Desorption and reuse of the adsorbent film were also studied which indicated that the film can be used repeatedly for selective Cu2+ sorption from aqueous solution. Nazia Rahman, Nobuhiro Sato, Satoru Yoshioka, Masaaki Sugiyama, Hirotaka Okabe, and Kazuhiro Hara Copyright © 2013 Nazia Rahman et al. All rights reserved. Studies on Wear Properties of Polystyrene in the Presence of Fibrillated Network of Polytetrafluoroethylene Sun, 28 Jul 2013 08:27:08 +0000 Polystyrene (PS) is an important commodity plastic; however, it is not known as a suitable material for tribological applications. It has a relatively high friction coefficient in contact with metallic surfaces and high abrasion loss factor. Polytetrafluoroethylene (PTFE) is a known friction modifier, has a low friction coefficient, and is extensively used to reduce the friction coefficient and wear rate (with engineering plastics to improve tribological properties). It is known for fluoroelastomers and engineering plastics that fine particles of PTFE have the greatest effect on improving the specified properties. Here, oriented, fibrillated network morphology of PTFE in PS matrix was prepared. The wear studies show a large reduction in both the friction coefficient (45% reduction) and the wear rate (2% incorporation of PTFE leads to a 49% reduction). But the friction coefficients do not show any significant change on increasing PTFE. A similar observation was made for the wear rate. Scanning electron microscope (SEM) images of the worn surfaces show a crack tip bridging mechanism, and it was observed that with the increase in PTFE content, the extent of crack tip bridging increases. This extensive improvement may be attributed to the unique morphology of the blend system. Sumanda Bandyopadhyay, Rajgopal Iyer, Rajdeep Majumder, B. Satapathy, and Anup K. Ghosh Copyright © 2013 Sumanda Bandyopadhyay et al. All rights reserved. Synthesis and Characterization of All Renewable Resources Based Branched Polyester: Poly(2,5-furandicarboxylic acid-co-glycerol) Sun, 21 Jul 2013 14:14:31 +0000 Condensation of all renewable resources based monomers 2,5-furandicarboxylic acid and glycerol in the presence of 2 mol% Sb2O3 catalyst at 210°C gives a branched polyester resin in 70% yield. This resin was characterized by elemental analysis, 1H, 13C NMR, FT-IR, and TGA-DTG. Ananda S. Amarasekara, Ashfaqur Razzaq, and Paul Bonham Copyright © 2013 Ananda S. Amarasekara et al. All rights reserved. Effect of Filler Dimensionality on Mechanical Properties of Nanofiller Reinforced Polyolefin Elastomers Wed, 26 Jun 2013 08:56:59 +0000 The object of this study has been to investigate the effect of filler dimensionality on morphology and mechanical properties of polymer nanocomposites using various kinds of nanofillers (such as multiwalled carbon nanotubes (1D filler), layered silicate (2D filler), and boehmite (3D filler)) dispersed in the matrix of ethylene-1-octene copolymer (EOC), a polyolefin-based elastomer. The morphological features were studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) while mechanical properties were characterized by tensile testing and depth sensitive recording microindentation hardness measurements. It has been demonstrated that the filler dimensionality may have dramatic influence on the mechanical properties of the samples. Based on the results obtained by tensile testing and microhardness measurements, the reinforcing effect of the nanofiller was found to follow the order: 1D filler > 2D filler > 3D filler. Sharmila Pradhan, Ralf Lach, Hong Hai Le, Wolfgang Grellmann, Hans-Joachim Radusch, and Rameshwar Adhikari Copyright © 2013 Sharmila Pradhan et al. All rights reserved. Effect of Sugar, Urea, and Molasses and the Influence of Radiation on the Plasticization of Acacia catechu Extract Incorporated Starch/Poly-(Vinyl Alcohol) Based Film Thu, 06 Jun 2013 10:23:30 +0000 Acacia catechu extract was incorporated in the starch/PVA (60% : 40%) based films (0% to 15%) to the total weight of starch/PVA based film. The tensile strength (TS) of the starch/PVA blend film was 24 MPa whereas the acacia incorporated film shows the highest tensile strength (TS) of 33.8 MPa at 0.5%. Again, 0.5% acacia based film was treated with 10% urea, sugar, and molasses separately both at nonirradiated and irradiated conditions. At the nonirradiated condition molasses incorporated film gives the best results (TS 16 MPa, EB 59%), while sugar incorporated film shows a value of 10 MPa TS and EB of 123% at 200 krad. The films were investigated by FTIR. Thermal studies were carried out by TG/DTA. Water absorption experiment showed a different uptake of water by the different films. Soil degradation test revealed that after 70 days molasses incorporated film (both irradiated and nonirradiated) degrades to 100% into the soil. Marufa Naznin and Md. Zainul Abedin Copyright © 2013 Marufa Naznin and Md. Zainul Abedin. All rights reserved. Poly(Arylene Ether Sulfone)s with HEPES Pendants: Synthesis, Thermal, and Dielectric Studies Wed, 29 May 2013 14:10:44 +0000 Polyethersulfone with active carboxylic acid pendants was prepared from solution polymerization via nucleophilic displacement polycondensation reaction among 4,4′-dichlorodiphenyl sulfone (DCDPS) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). The conditions necessary to synthesize and purify the polymer were investigated in some details. The synthesized polyethersulfone comprises sulfone and ether linkages in addition to reactive carboxylic acid functionality; this reactive carboxylic acid group was exploited to hold the HEPES moiety via ester linkage and is achieved by simple DCC coupling condition at ambient temperature. Without impairing the primary polymeric backbone, three modified polymers were prepared by varying the stoichiometric ratio of HEPES. Characterization of the polymers by 1H & 13C NMR, FT-IR, and TGA demonstrated that HEPES was quantitatively incorporated into the prime polymer. All the prepared polymers were pressed into tablets, and electrical contacts were established to study the dielectric properties. Finally, the influence of the HEPES on the dielectric properties was examined. S. D. Ganesh, M. N. K. Harish, B. J. Madhu, Husnasarvari Maqbool, K. V. Pai, and M. Y. Kariduraganavar Copyright © 2013 S. D. Ganesh et al. All rights reserved. Mechanical and Abrasive Wear Behavior of Metal Sulphide Lubricant Filled Epoxy Composites Tue, 28 May 2013 18:45:33 +0000 The present work reveals the effect of the addition of commercial MoS2 (10 wt%) particles on mechanical and two-body abrasive wear behavior of epoxy with/without glass fiber mat reinforcement. The composites were fabricated using casting and simple hand lay-up techniques followed by compression molding. The mechanical properties such as density, hardness, tensile, and flexural properties were determined as per ASTM standards. The abrasive wear testing was carried out using pin-on-disc wear tester for different loads and abrading distances at constant speed of 1 m/s. A significant reduction in wear loss and specific wear rate was noticed after the incorporation of MoS2 filler allowing less wear of matrix during abrasion which in turn facilitated lower fiber damage. However the incorporation of MoS2 particles had a detrimental effect on most of the mechanical properties of the composites. The worn surface features were investigated through scanning electron microscopy (SEM) in order to investigate the wear mechanisms. M. Sudheer, N. Karthik Madhyastha, M. Kewin Amanna, B. Jonthan, and K. Mayur Jayaprakash Copyright © 2013 M. Sudheer et al. All rights reserved. Physicochemical, Thermomechanical, and Swelling Properties of Radiation Vulcanised Natural Rubber Latex Film: Effect of Diospyros peregrina Fruit Extracts Mon, 13 May 2013 15:20:43 +0000 A range of radiation vulcanised natural rubber latex (RVNRL) films were prepared using various concentrations of aqueous extracts of mature Diospyros peregrina fruit, which acted as a cross-linking agent. The surface of the RVNRL films exhibited an aggregated morphology of the rubber hydrocarbon with increasing roughness due to increasing fruit extract contents in the latex. An improvement in tensile strength, tensile modulus, and storage modulus of RVNRL films was observed with the addition of fruit extracts compared to the control film due to their cross-linking effect. The glass transition () temperature of all the RVNRL films was found to be at around −61.5°C. The films were also observed to be thermally stable up to 325°C, while the maximum decomposition temperature appeared at around 375°C. The incorporation of fruit extracts further revealed a significant influence on increasing the crystallinity, gel content, and physical cross-link density of the RVNRL films. Kazi Md Zakir Hossain, Nashid Sharif, N. C. Dafader, M. E. Haque, and A. M. Sarwaruddin Chowdhury Copyright © 2013 Kazi Md Zakir Hossain et al. All rights reserved. Temperature Dependent Mechanical Analysis of Chalcogenide (CdS, ZnS) Coated PET Films Wed, 03 Apr 2013 15:21:20 +0000 Commercial polyethylene terephthalate (PET) film has been used as flexible substrate, and chalcogenide materials such as CdS, ZnS have been coated separately on PET film using vacuum thermal evaporation method. The structural characterisation of CdS-PET and ZnS-PET films has been performed by X-ray diffraction (XRD) pattern and Fourier transforms infrared (FTIR) spectroscopy. The surface morphology of CdS-PET and ZnS-PET films has also been investigated using scanning electron microscope (SEM). Temperature dependent mechanical study of chalcogenide-PET films has been carried out using Dynamic Mechanical Analyser (DMA). The stress-strain curves of chalcogenide coated PET films at room and elevated temperatures explain the mechanical response of these films under the different temperature. Sandhya Gupta, Kananbala Sharma, and N. S. Saxena Copyright © 2013 Sandhya Gupta et al. All rights reserved. Fatigue Failure Model for Polymeric Compliant Systems Sun, 31 Mar 2013 18:34:01 +0000 Fatigue analysis and lifetime evaluation are very important in the design of compliant mechanisms to ensure their safety and reliability. Earlier models for the fatigue prediction of compliant mechanisms are centred on repeated and reversed stress cycles. Compliant mechanisms (CMs) are now being applied to situations where the fatigue is caused by random varying stress cycles. It is, therefore, necessary to consider fatigue resulting from random varying stress cycles and damage caused to the compliant material. A continuum damage mechanics (CDM) model is proposed to assess the fatigue life of polymeric compliant mechanisms. The elastic strain energy is computed on the basis of a nearly incompressive hyperelastic constitution. The damage evolution equation is used to develop a mathematical formula that describes the fatigue life as a function of the nominal strain amplitude under cyclic loading. Low density polypropylene (LDP) is used for the fatigue tests conducted under displacement controlled condition with a sine waveform of 10 Hz. The results from the theoretical formula are compared with those from the experiment and fatigue software. The result from the prediction formula shows a strong agreement with the experimental and simulation results. Theddeus T. Akano and Omotayo A. Fakinlede Copyright © 2013 Theddeus T. Akano and Omotayo A. Fakinlede. All rights reserved. Study of Dielectric Relaxation Behavior of Liquid Crystal Copolyester Vectra-A by Thermally Stimulated Discharge Current Technique Wed, 27 Mar 2013 11:15:18 +0000 The dielectric relaxation behavior of thermotropic liquid crystal copolyester of 73% of p-hydroxy-benzoic acid (HBA) and 27% of 2-hydroxy-6-naphthoic acid (HNA) (Vectra-A) at poling temperature 80°C has been studied using thermally stimulated depolarization current (TSDC) technique in the temperature range from 15°C to 250°C. The TSD currents were obtained for different polarizing fields ranging from 3.8 kV/cm to 19.2 kV/cm. TSD current spectra in the temperature range from 15°C to 250°C show three current maxima around 25°C, 110°C, and 220°C. The maxima around 25°C and 110°C correspond to characteristic dipolar relaxations β and α, respectively. The peak around 220°C is due to space charge effects named as δ-relaxation. The various relaxation parameters like activation energy (U), relaxation strength , preexponential factor , the quantity of charge released (Q) and concentration of trap for β- and α-relaxations at polarizing temperature 80°C for different polarizing fields were evaluated using Bucci-Fieschi fit. The linear variation between activation energy and natural logarithm of preexponential factor indicates the presence of compensation effect for dipolar relaxations of Vectra-A under present poling conditions. Sapna Kalia, J. K. Sharma, and Vandana Sharma Copyright © 2013 Sapna Kalia et al. All rights reserved. 50 Years of the K-BKZ Constitutive Relation for Polymers Sun, 24 Mar 2013 11:46:35 +0000 The K-BKZ constitutive model is now 50 years old. The paper reviews the connections of the model and its variants with continuum mechanics and experiment, presenting an up-to-date recap of research and major findings in the open literature. In the Introduction a historical perspective is given on developments in the last 50 years of the K-BKZ model. Then a section follows on mathematical modeling of polymer flows, including governing equations of flow, rheological constitutive equations (with emphasis on viscoelastic integral constitutive equations of the K-BKZ type), dimensionless numbers, and boundary conditions. The Method of Solution section reviews the major developments of techniques necessary for particle tracking and calculation of the integrals for the viscoelastic stresses in flow problems. Finally, selected examples are given of successful application of the K-BKZ model in polymer flows relevant to rheology. Evan Mitsoulis Copyright © 2013 Evan Mitsoulis. All rights reserved. Preparation of Nanocomposite Based on Exfoliation of Montmorillonite in Acrylamide Thermosensitive Polymer Sun, 17 Mar 2013 10:32:30 +0000 Poly(N-isopropylacrylamide) (PNIPAM) was synthesized in the presence of AIBN as radical initiator. The structure of polymer was elucidated using IR, 1H NMR, and 13C NMR spectroscopies and TGA thermogram. Exfoliated nanocomposite based on thermosensitive polymer (PNIPAM) was prepared utilizing montmorillonite (MMT) by solution blending. Its dispersion characteristics were investigated using SEM, X-ray diffraction, and particle size analysis. XRD showed exfoliation of MMT in polymer matrix above lower critical solution temperature (LCST). SEM indicated that polymer chains were dispersed among the layers of MMT. Particle size analysis showed two distinctive regions at 311 (31/5%) and 1160 (68/5%) nm. Nader Zabarjad Shiraz, Elham Enferad, Aazam Monfared, and Mohammad Ali Mojarrad Copyright © 2013 Nader Zabarjad Shiraz et al. All rights reserved. Biodiesel as a Plasticizer of a SBR-Based Tire Tread Formulation Mon, 11 Mar 2013 17:55:25 +0000 The solubility parameter of a series of methyl esters of fatty acids, the components of biodiesel, was calculated using the group incremental method proposed by Van Krevelen. The solubility parameter of biodiesel was compared with that of a series of rubbers like EPDM, butyl rubber, polyisoprene, polybutadiene, SBR (with different content of styrene), and nitrile rubber (with different content of acrylonitrile) showing that biodiesel is an effective solvent of all the above mentioned rubbers with the exclusion of nitrile rubber. Indeed, it was experimentally verified that polyisoprene, polybutadiene and SBR are easily soluble in biodiesel while polystyrene gives a cloudy solution. Considerations on the solubility parameter of the biodiesel and of a series of rubbers have led to the conclusion that biodiesel behaves essentially as an internal lubricant in a diene rubber matrix, the same situation occurs with the common aromatic mineral oil plasticizer known as T-RAE. The experimental evaluation of biodiesel as plasticizer in an SBR-based rubber compound in comparison to an aromatic mineral oil have led to the primary conclusion that biodiesel is reactive with the sulphur curing agent subtracting sulphur to the crosslinking polymer chains and leading to a vulcanizatewith lower moduli, tensile and hardness and higher elongationsin comparison to a reference compound fully plasticized with an aromatic mineral oil. However, biodiesel seems a good low temperature plasticizer because the low elastic modulus observed is desired in a winter tire tread for a good grip on snow and ice. The present work is only an exploratory work, and the tire tread formulation with biodiesel was not optimized. Franco Cataldo, Ornella Ursini, and Giancarlo Angelini Copyright © 2013 Franco Cataldo et al. All rights reserved. Blending of Cellulose and Chitosan in Alkyl Imidazolium Ionic Liquids Mon, 03 Dec 2012 08:54:45 +0000 The production of cellulose/chitosan blends in alkyl imidazolium ionic liquids (ILs) was studied in this work. Selected organic solvents, such as dimethyl sulfoxide, ethyl acetate, and diethyl ether, were used as cosolvents. The addition of cosolvents decreased the viscosity of cellulose/chitosan solutions in ILs and facilitated the dissolution of polysaccharides, thereby decreasing the and polymer aggregates sizes in the solutions. The cellulose/chitosan films were produced from the studied solutions. The presence of one of cosolvent and ILs in the blended films was confirmed by FTIR spectroscopy. The blended film is stronger than pure cellulose film, and the addition of cosolvents has an influence on its mechanical properties. Olga Kuzmina, Thomas Heinze, and Dariusz Wawro Copyright © 2012 Olga Kuzmina et al. All rights reserved. Swelling of Elastomers in Solutions of Nanoparticles Mon, 26 Nov 2012 08:49:20 +0000 Elastomers used in protective gloves can be sensitive to the action of solvents used to disperse commercial solutions of nanoparticles. These effects may include the swelling of the polymer, leading to a modification of its mechanical and chemical properties. Modifications to the properties of the polymer will impact the protection provided by the protective gloves. The goal of this work was therefore to study the swelling of several elastomers when exposed to commercial solutions of nanoparticles. The study involved four elastomers and three commercial solutions of colloidal titanium dioxide (). Swelling was assessed by measurements of mass gain and length change. Tests were also performed with technical and ultrapure solvents corresponding to the liquid carriers. The solutions had a significant effect on the swelling of nitrile rubber, latex, and neoprene. A large mass gain was recorded for short immersion times, indicating a possible penetration of the nanoparticle liquid carrier into these elastomers. Length change measurements revealed a swelling anisotropy effect with nitrile rubber and latex in the solutions of colloidal . No effect was measured with butyl rubber. The results show that great care must be taken when selecting protective gloves for the handling of nanoparticle dispersions. Ludwig Vinches, Gérald Perron, Patricia Dolez, Kevin J. Wilkinson, and Stéphane Hallé Copyright © 2012 Ludwig Vinches et al. All rights reserved.