bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repeated impacts tests and nanoindentation as complementary tools for mechanical characterization of polymer‐coated particles
Authors: Perfetti G. , Arfsten J. , Kwade A. , Wildeboer W. J. , Meesters G. M. H. 
Published: May 2010

AbstractPolymer‐coated particles have been produced by applying two grades of hydroxypropyl methylcellulose and one grade of polyvinyl alcohol onto sodium benzoate Purox‐S core particles by using top‐spray fluid bed coater and then stored under two different conditions, namely ambient conditions (23°C, 55% RH) and in the freezer (−18°C, 25% RH). Surface morphology has been firstly analyzed using scanning electron microscope and atomic force microscope. Resistance to attrition and viscoelastic properties have been measured by repeated impact tester (RIT) and nanoindentation, respectively. The resistance to attrition have been discussed as function of type of coating materials, breakage mechanisms, and storage temperature, and then compared with uncoated Purox‐S. The storage conditions is not influencing the morphology, whereas is strongly affecting the resistance to attrition. Coated particles stored at −18°C were found to be more resistant to attrition than ones stored at room conditions. Such differences negligible at low energies (low numbers of impacts) increase as soon as the number of impacts and the energy rise. The improvement in the resistance to attrition was related to the plasticizing effect of water content. Displacement, storage modulus (E′), loss modulus (E″), and damping factor (tan δ) have been measured for all coated particles. Quasistatic and dynamic nanoindentation were found to agree very well with each other. Comparison of the nanoindentation results and the RIT results showed that tan δ, as measure of viscoelasticity and flexibility of the polymeric coating material, is related to the attrition behavior. It was found, in fact, that a higher tan δ gives more resistance to attrition. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The mesh disturbance effects in a low‐temperature cascade arc torch for surface modification of low density polyethylene
Authors: Gilliam Mary , Ritts Andrew , Yu Qingsong 
Published: May 2010

AbstractA stainless steel mesh was placed in a low‐temperature cascade arc torch (LTCAT) to study its disturbance effects on the plasmas and on the surface modification of low density polyethylene (LDPE). It was found that the photoemitting species were deflected by the screen and only faint glow was observed after the mesh. Optical emission spectroscopy examination indicated that the amount of electronically excited species in the plasma was greatly reduced after passing through the mesh. Grounding the mesh altered the nature of the discharge and a greater intensity of O emission was observed in Ar LTCAT + O2 discharge, which indicated greater energy transfer to the oxygen. Although a decrease in surface damage was observed on the treated LDPE samples by placement of the mesh in the Ar LTCAT discharges, the wettability achieved was also greatly reduced. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Modification of poly acrylic acid using calix[4]arene derivative for the adsorption of toxic heavy metals
Authors: Hajipour Abdol Reza , Habibi Sakineh , Ruoho Arnold E. 
Published: May 2010

AbstractPoly acrylic acid (PAA) was grafted with p‐t‐butyl calix[4]arene diamine (distal cone) (2) to adsorb toxic heavy metal and alkali metal cations. The grafting method includes the amidation reaction of PAA with calixarene diamine derivative 2 which was carried out in N,N‐dimethylformamide (DMF) and N–methyl‐2‐pyrrolidone (NMP) as solvents. The modified PAAs (PAA‐C1 and PAA‐C2) were characterized by FTIR, 1H‐NMR, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). PAA‐C1 and PAA‐C2 were used to evaluate the sorption properties of some toxic heavy metal cations (Co2+, Cu2+, Cd2+, Hg2+), alkali metal cations (Na+, K+, Cs+), and Ag+. Results showed that the modified PAAs were good sorbents for heavy metal and alkali metal cations. The main goal of this project is to design hydrophobically modified PAA that is suitable for ion selective membranes and chemical sensor devices for adsorption of toxic heavy metals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crystal structure, curing kinetics, and thermal properties of bisphenol fluorene epoxy resin
Authors: Xiong Yuanqin , Liu Hanping , Ou Encai , Zeng Xiaoliang , Zhou Wei , Xu Weijian 
Published: May 2010

AbstractDiglycidyl ether of 9,9‐bis(4‐hydroxyphenyl) fluorene (DGEBF) monomer was successfully synthesized and characterized in detail. The crystal structure of DGEBF was measured by single‐crystal X‐ray diffraction analysis. Curing kinetics of DGEBF with 4,4‐diaminodiphenyl sulfone (DDS), thermal properties, and decomposition kinetics were investigated using nonisothermal differential scanning calorimetry (DSC) according to Kissinger, Ozawa and Crane methods. The glass transition temperature (Tg), thermal properties of cured polymer were estimated by DSC, dynamic mechanical analysis, and thermogravimetric analyses. Epoxy value of DGEBF monomer up to theoretical value leads to higher crosslink density of cured polymers. The cured DGEBF/DDS system exhibited obvious higher Tg and better thermal stability compared to those of DGEBF/diamine systems reported previously. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Polymerization of linseed oil with phenolic resins
Authors: Çaylı Gökhan , Küsefoğlu Selim 
Published: May 2010

AbstractIn this study, linseed oil was directly polymerized with different oil soluble resoles. p‐Ethyl (PEP), p‐tertiary butyl (PTB), p‐tertiary octyl (PTO), and p‐phenyl (PPP) phenols were separately reacted with formaldehyde to give linseed oil soluble resoles. These were then reacted with linseed oil to give transparent rubbery polymers. A model reaction was performed with methyl oleate and PTB phenol resole to clarify the reaction mechanism. Reaction products were characterized with 1H‐NMR and IR techniques. Spectral examination of the model reaction showed that polymerization reaction proceeded via ene reaction of the quinone methide formed at the end group of the resole with the allylic positions of the fatty ester. Rubbery polymers were obtained with linseed oil using 10 to 40% of the different resoles. Hard, load bearing and tough materials were obtained at 40% phenolic resin loading. Mechanical properties of the materials were characterized by dynamic mechanical analyzer (DMA) and stress–strain tests. The best mechanical and thermal properties were obtained with PEP resole which showed a storage modulus of 350 MPa and a tan δ peak at 65°C. Storage moduli of 275, 250, and 30 were obtained for PPP, PTB, and PTO resoles‐linseed oil polymers, respectively. At the same phenolic resin loading, elongation at break and swelling ratios in CH2Cl2 increased with the longer alkyl substitution on the resole resins. The highest thermal stability was observed by PEP resole–linseed oil polymer which has a 5% weight loss temperature of 340°C as determined by TGA. The lowest thermal stability was observed for PTB resole‐linseed oil polymer at 220°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Experimental and statistical study of the effects of material properties, curing agents, and process variables on the production of thermoplastic vulcanizates
Authors: Trifkovic M. , Sheikhzadeh M. , Choo K. , Rohani S. 
Published: May 2010

AbstractA comprehensive experimental study together with statistical analysis was performed to identify the optimal process conditions, materials selection, and curing system for the production of thermoplastic vulcanizates (TPVs) based on EPDM rubber and polypropylene. Two types of curing systems were studied together with five different types of EPDM rubber. The TPV products were assessed according to elastic modulus and degree of swelling (indicators of crosslink density), ultimate tensile strength, ultimate elongation, tear strength, and compression set. A design of experiments method was applied to minimize the number of experiments and to obtain response surface and regression models for this complex and highly interactive system. From the modeling results, optimum values for the influential factors were obtained to achieve the target end product properties. It was found that a phenolic resin‐based curing system gave the best product properties and that the most influential factors were the rubber characteristics (ethylene content, ethylidene norbornene content, and molecular weight) and the polypropylene content in the formulation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Control of thermo reversible gelation of methylcellulose using polyethylene glycol and sodium chloride for sustained delivery of ophthalmic drug
Authors: Bain Mrinal Kanti , Bhowmik Manas , Maity Dipanwita , Bera Nirmal Kumar , Ghosh Santinath , Chattopadhyay Dipankar 
Published: May 2010

AbstractThe effect of molecular weight of polyethyleneglycol (PEG) and sodium chloride (NaCl) on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ophthalmic drug. The gelation temperature of 1% MC was 60 ± 0.40°C. It was found that the gelation temperature of MC was reduced with the addition of 10% PEG and extent of reduction of gelation temperature was depended on the molecular weight of PEG at same PEG concentration of 10%. The gelation temperature of MC was reduced by 10.4 to 5.9°C with the increasing molecular weight of PEG starting from 400 to 20,000 (Mn) depending on the method of determination of gelation temperature. To reduce the gelation temperature of MC close to physiological temperature (37°C), 6% NaCl was added in the different MC‐PEG combinations containing different molecular weight of PEG. It was observed that the drug release time increased from 5 to 8 h with the increase in molecular weight of PEG from 400 to 20,000 (Mn) and this was due to the maximum viscosity and gel strength of MC‐PEG20000‐NaCl ternary combination. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Mechanical and dynamic mechanical analysis of hybrid composites molded by resin transfer molding
Authors: Ornaghi Heitor Luiz , Bolner Alexandre Sonaglio , Fiorio Rudinei , Zattera Ademir Jose , Amico Sandro Campos 
Published: May 2010

AbstractThis work aims to evaluate the performance of glass/sisal hybrid composites focusing on mechanical (flexural and impact) and dynamic mechanical analyses (DMTA). Hybrid composites with different fiber loadings and different volume ratios between glass and sisal were studied. The effect of the fiber length has also been investigated. The densities of the composites were compared with the theoretical values, showing agreement with the rule of mixtures. The results obtained in the flexural and impact analysis revealed that, in general, the properties were always higher for higher overall reinforcement content. By DMTA, an increase in the storage and loss modulus was found, as well as a shift to higher values for higher glass loading and overall fiber volume. It was also noticed an increase in the efficiency of the filler and the calculated activation energy for the relaxation process in the glass transition region. The fiber length did not significantly change the results observed in all analyses carried out in this work. The calculated adhesion factor increased for higher glass loadings, meaning the equation may not be applied for the system studied and there are other factors, besides adhesion influencing energy dissipation of the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of different salts on PVAc/PVdF‐co‐HFP based polymer blend electrolytes
Authors: Ulaganathan M. , Rajendran S. 
Published: May 2010

AbstractSolid polymer electrolytes comprising poly(vinyl acetate) (PVAc), and poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐co‐HFP), low molecular weight plasticizer [Ethylene Carbonate (EC)] and different lithium salts (LiBF4, LiClO4, and LiCF3SO3) are prepared by solution casting technique. The electrolyte films are subjected to various characterization techniques such as XRD, FTIR, DSC, SEM and ac impedance analysis. Ionic conductivity is obtained as a function of frequency at various temperatures ranging from 302 to 363 K. The maximum room temperature ionic conductivity is found to be 1.18 × 10−3 S cm−1 for the film containing LiBF4 and the temperature dependent ionic conductivity values seem to obey VTF relation. Microstructure of the samples has been depicted by means of scanning electron microscope. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structure and properties of biaxial‐oriented crystalline polymers by solid‐state crossrolling
Authors: Yang Y. , Keum J. , Zhou Z. , Thompson G. , Hiltner A. , Baer E. 
Published: May 2010

AbstractThe effect of biaxial orientation by solid‐state crossrolling on the morphology of crystalline polymers including polypropylene (PP), high density polyethylene (HDPE) and Nylon 6/6 was investigated with polarized optical microscopy, atomic force microscopy, wide‐angle X‐ray scattering, and small‐angle X‐ray scattering techniques. It was found that crossrolling gradually changed the initial spherulitic structure into a biaxially oriented crystal texture with chain axis of crystals becoming parallel to the rolling direction for all three polymers. The effect of microstructure change on the macromechanical properties was studied in tension at both ambient temperature and −40°C. In tension at room temperature, the localized necking deformation of HDPE and PP control changed upon orientation into homogeneous deformation for the entire sample length. This was attributed to that the oriented crystal morphology eliminated the stress concentration, which existed in the original spherulitic structure from lamellae orientation in the polar and equatorial regions. At ambient conditions, the elastic moduli of HDPE and PP were found to decrease slightly with orientation whereas the modulus of Nylon 6/6 increased with increasing orientation. This was due to the fact that the amorphous chains of HDPE and PP are in a rubbery state and orientation increased the shear relaxation in the orientation direction but the amorphous chains of Nylon 6/6 are in the glassy state inhibited the shear relaxation. Both the yield stress and strain hardening exponent increased with increasing orientation for all three polymers. In tension at −40°C, orientation changed the failure mechanism of all three polymers from brittle fracture into ductile failure, as the original spherulitic structure was changed into an oriented structure with chain axis of crystals becoming parallel to the tension direction, which allowed chain slip deformation of crystals and resulted in oriented samples showing ductile failure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effects of isocyanate index on the properties of aliphatic waterborne polyurethaneureas
Authors: Wang Ke , Peng Ya , Tong Rongbai , Wang Yan , Wu Zengyong 
Published: May 2010

AbstractThe aliphatic waterborne polyurethaneureas (WPU) with different isocyanate index (R) were synthesized by isophorone diisocyanate (IPDI) and polyester glycol via prepolymer mixing method. The effects of the R value on the structure and the properties of the resultant polymers have been analyzed. The polymer with a certain R value (R = 1.44) exhibited excellent mechanical properties with both high tensile strength (55 MPa) and high elongation at break (1400%). The water resistance and the thermal stabilities of WPUs have been improved with the increase of R. The results were interpreted in terms of the structures associated with the micro‐phase separation. According to differential scanning calorimeter (DSC) analysis, the microphase separation degree was elevated by increasing R value. FTIR spectrum showed the more R value, the more hydrogen bonded urea groups. No crystallinity was found in X‐ray diffraction (XRD) patterns showing the typical amorphous morphologies of IPDI‐based WPUs. Thus the primary driving force for microphase separation was the hydrogen bonding between urethane and urea groups, making significant influence on the properties of WPUs, as shown in dynamic mechanical analyzes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Molecular activation energies (Δμ*2) of L‐lysine, L‐tyrosine, L‐proline, DL‐alanine, glycerol, orcinol, iodine, DTAB, and TMSOI for blending with melamine‐formaldehyde‐polyvinylpyrrolidone polymer resin illustrated with SEM
Authors: Singh Man , Kumar Vinod , Kale R. K. , Jain C. L. 
Published: May 2010

AbstractEfficient molecular mixing together is a key precondition for industrial exploitation of individual macromolecules for potential product development and quality assurance with resource saving mechanism. Conceptually, MFP (melamine‐formaldehyde‐polyvinylpyrrolidone) polymer resin was mixed with amino acids (L‐lysine, L‐tyrosine, L‐proline, DL‐alanine), nonionic surfactants (glycerol, orcinol), iodine as metal and cationic surfactants (DTAB, TMSOI) as dispersants, in 4 : 1 ratio, w/w. A mutual molecular dispersion occurs at a cost of molecular activities with utilization of a sufficient amount of activation energies. The activation energies (Δμ*2, kJ mol−1) were derived from intrinsic viscosities ([η], kg/L) and partial molar volumes (V2, 10−6 m3/mol), which were calculated from experimental data of viscosities (η, N s m−2) and apparent molar volumes (V2, 10−6 m3/mol) of 0.005, 0.007, 0.009, and 0.0011 g/mL aqueous samples of the dispersants at 304.15 K. The limiting data were fitted to standard activation energy equations and were analyzed to assess potential of their micromixing. Densities (ρ/103 kg m−3) for apparent molar volume (V2/10−6 m3 mol−1) and viscosity (η, 0.1N, s m−2 = 0.1 kg m−1 s−1, = 1 poise, SI unit) were also measured with weight method. The Δμ*2< 0, in arrange of −48.35 to −118.03 kJ/mol were noted that inferred effective micromixing evidenced with SEM images of the blends. The Δμ*2, kJ mol−1 data are as glycerol (−118.03) > TMSOI (−117.55) > DTAB (−102.93) > orcinol (−101.54) > MFP‐R (−93.71) > iodine (−59.32) > L‐proline (−59.27) > L‐lysine (−55.87) > DL‐alanine (−55.04) > L‐tyrosine (−53.04) > water (−48.35) orders with maximum utilization of Δμ*2, glycerol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A systematic study on notched impact strength of super‐toughened polyamide 6 nanocomposites using response surface methodology
Authors: Ramezani‐Dakhel Hadi , Garmabi Hamid 
Published: May 2010

AbstractResponse surface methodology was utilized to optimize the impact strength of polyamide 6 based nanocomposites using three different types of tougheners (ethylene‐methyl acrylate, ethylene‐ethyl acrylate‐maleic anhydride, and hydrogenated butadiene acrylonitrile rubber) at three different levels of clay and rubber. Melt mixing method using a lab scale twin screw extruder was applied to prepare the samples. The wide‐angle X‐ray diffraction, transmission electron microscopy, and atomic force microscopy results indicated intercalated/exfoliated morphology for all of the prepared nanocomposites. The tensile properties as well as the Izod impact strength of the designed samples were evaluated. Impact resistance was correlated to material variables by using a second order polynomial function. The best balanced mechanical properties, between 15 designed experiments, was achieved using ethylene‐ethyl acrylate‐maleic anhydride as toughener, 4 wt % of clay and 17.5 wt % of the toughener, whereas 900% improvement in impact strength and 15% enhancement of Young's modulus was obtained compared with pristine polyamide 6 resin. The formulation meeting the simultaneous optimization of Young's modulus and impact strength was proposed based on mathematical quadratic modeling. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic modeling of polypropylene thermal oxidation during its processing by rotational molding
Authors: Sarrabi S. , Colin X. , Tcharkhtchi A. 
Published: May 2010

AbstractThe main drawback of rotational molding is a long stay (several dozens of minutes) of polymer in melt state at high temperature in atmospheric air. To prevent any significant polymer thermal degradation, it is necessary to define, preliminary, a processing window in a temperature‐molar mass map. The objective of this article is to elaborate and check the validity of a general thermal degradation model devoted to determine, in a near future, some important boundaries of this processing window. This model is composed of two distinct levels: (i) The first level is derived from the thermal transfer mechanisms occurring during a processing operation, polymer phase changes (i.e., melting and crystallization) being simulated by the enthalpy method; and (ii) The second level is derived from the oxidation mechanistic scheme of free additive polymer in melt state established in a previous study, but completed, here, by adding the main stabilization reactions of a common synergistic blend of antioxidants, widely used for rotational molding polymer grades. By juxtaposing such “thermal” and “chemical” levels, it is possible to predict the polymer thermal degradation during a whole processing operation. The validity of both levels is successfully checked in real rotational molding conditions for polypropylene (PP). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000–000, 2010
Elaboration and characterization of composites of castor oil‐based polyurethane and fibers from alfa stems
Authors: Maafi El Miloud , Tighzert Lan , Malek Fouad 
Published: May 2010

AbstractPolyurethane (PU) based on castor oil and hexamethylene diisocyanate (HDI) was synthesized by a two‐step method in the presence of dibutyltin dilaurate (DBTDL) as catalyst. The PU obtained was blended with various amounts of cellulose fibers extracted from alfa stems to prepare composite materials. The influence of cellulose fibers on the thermal and mechanical properties of different composites was demonstrated by means of several characterization techniques, such as thermomechanical, structural, and morphological analyses. The hydrogen bonding interaction and the possible formation of urethane links between PU and hydroxyl groups of cellulose provide a good fiber‐matrix interface. The infrared absorption vibration of the NH bond, which is 3336 cm−1 for pure PU, in fact shifts to 3319 cm−1 for a composite containing 25% of cellulose. Moreover, the variation of glass transition temperature, Tg, versus cellulose content is linear, for example, Tg of pure PU and of a composite containing 40% of cellulose is −35 and −24°C, respectively. Furthermore, the mechanical properties rise steadily up to 20 wt % of fibers and decrease beyond this value. The novelty of this article lies in the fact that over 95% of starting materials used are obtained from agro‐resource. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010