bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of cardanol‐grafted natural rubber—The solution technique
Authors: Vikram T. , Nando G. B. 
Published: April 2007

AbstractCardanol, a by‐product of the cashew industry, has been recently proven to be a multifunctional additive (MFA) in rubbers. It is expected that grafting of cardanol onto natural rubber (NR) would impart inherent MFA characteristics to the rubber. Grafting has been carried out in solution using toluene as the solvent and a peroxide initiator. Optimized conditions of grafting reaction could be arrived at using a statistical tool namely orthogonal array testing strategy, keeping the maximum percentage of grafting as the selection criteria. Further studies were conducted to study the influence of monomer concentration and initiator concentrations. The effect of the reaction temperature and reaction time were also investigated. Characterization of grafted rubber was carried out with the help of infrared spectroscopy, nuclear magnetic resonance spectroscopy and thermal analysis. IR spectrum of cardanol exhibited the characteristic peak of cardanol at 3356 cm−1. Percent grafting (PG) of cardanol onto NR was determined by residual weight method. PG increased with increasing cardanol quantity reached an optimum and then decreased. The increase in reaction time and reaction temperature also caused increasing levels of the grafted cardanol. However, PG continuously increased with increasing initiator concentrations. Differential scanning calorimetry studies of the grafted NR showed a lower glass transition temperature than that of the raw NR, which is indicative of the plasticization effect of cardanol. The thermogravimetric analysis showed a higher thermo oxidative stability for cardanol‐grafted NR. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Comparison of model‐fitting kinetics for predicting the cure behavior of commercial phenol–formaldehyde resins
Authors: Wang Jinwu , Laborie Marie‐Pierre G. , Wolcott Michael P. 
Published: April 2007

AbstractPhenol–formaldehyde (PF) resins have been the subject of many model‐fitting cure kinetic studies, yet the best model for predicting PF dynamic and isothermal cure has not been established. The objective of this research is to compare and contrast several commonly used kinetic models for predicting degree of cure and cure rate of PF resins. Toward this objective, the nth‐order Borchardt–Daniels (nth‐BD), ASTM E698 (E698), autocatalytic Borchardt–Daniels (Auto‐BD), and modified autocatalytic methods (M‐Auto) are evaluated on two commercial PF resins containing different molecular weight distributions and thus cure behaviors. The nth‐BD, E698, and M‐Auto methods all produce comparable values of activation energies, while Auto‐BD method yields aberrant values. For dynamic cure prediction, all models fail to predict reaction rate, while degree of cure is reasonably well predicted with all three methods. As a whole, the nth‐BD method best predicts degree of cure for both resins as assessed by mean squared error of prediction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Study of the effects of melt blending speed on the structure and properties of phosphate glass/polyamide 12 hybrid materials
Authors: Urman Kevin , Iverson Douglas , Otaigbe Joshua U. 
Published: April 2007

AbstractThe effects of melt blending conditions on the rheology, crystallization kinetics, and tensile properties of phosphate glass/polyamide 12 hybrid systems were investigated for the first time, to understand their complex processing/structure/property relationships. Increasing amounts of phosphate glass (Pglass) caused an increase in hybrid viscosity. Hybrid viscosity was also affected by processing (melt‐mixing) speed and small‐amplitude oscillatory shear tests and scanning electron microscopy (SEM) were used for a qualitative examination of the hybrid morphology. The addition of Pglass caused a decrease in hybrid crystallinity that was unaffected by processing (melt‐mixing) speed. The two‐parameter Avrami equation was applied successfully to the hybrid systems, and Pglass was found to nucleate the growth of polyamide 12 crystals. The nucleation effect was found to be dependent on concentration and processing history. The tensile properties of the hybrids were also studied, and the Halpin–Tsai equation was applied to the results to determine the maximum packing fraction of the Pglass. These results provide a basis for the prediction of hybrid mechanical properties for different Pglass concentrations and processing histories. Further, because of their facile processibility and desirable characteristics, such as the strong physicochemical interaction between the hybrid components and favorable viscoelasticity, these Pglass/polyamide 12 hybrids can be used as model systems for exploring feasibility of new routes for driving organic polymers and inorganic Pglass to self‐assemble into useful organic/inorganic hybrid materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer
Authors: Wang Jia Sheng , Chen Xu Dong , Mai Bi Yun , Zhang Ming Qiu , Rong Min Zhi 
Published: April 2007

AbstractTo prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH2 provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Applications of rheological torque–time curves to the study of thermooxidative degradation of polypropylene powder
Authors: Wang Xiao , Chen Xiaoyun , Yu Wencan , Ji Yaodong , Hu Xiaobo , Xu Jiarui 
Published: April 2007

AbstractThe torque–time curves of polypropylene (PP) powder treated under various thermooxidative degradation conditions were obtained through processing in the mixing chamber of a rheometer. Meanwhile, the Fourier transform infrared (FTIR) spectra of the corresponding samples were determined, and the quantitative analysis of the carbonyl indices of the FTIR spectra of the samples of the PP powder was carried out to provide evidence for the rheological characterization. PP granules, to which an antideteriorant was added before they were commercially supplied so good antidegradation could be achieved, was investigated for the sake of contrast. The analysis of the experimental results showed that the height of the torque–time curve of the PP powder and the corresponding value of the equilibrium torque could be used to characterize or evaluate the variations of the thermooxidative degradation of the PP powder. Under the same processing conditions, the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque decreased with the enhancement of the thermooxidative degradation treatment before mixing; on the contrary, the heights and areas of the characteristic bands of the carbonyl groups in the FTIR spectra of the PP powder and the corresponding values of the carbonyl index increased. The quantitative analysis of the FTIR spectra provided evidence for the conclusion that the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque could be used to characterize or evaluate the thermooxidative degradation of the PP powder. If the treatment under thermooxidative degradation conditions weakened or the degradation of the PP powder just began (i.e., in the viscosity range for processability), the evaluation method using the heights of the torque–time curves of the PP powder or the corresponding values of the equilibrium torque could provide more sensitivity than the method using the values of the carbonyl index. Consequently, the method using the heights of the torque–time curves to evaluate the thermooxidative degradation of the PP powder had its advantages. The application of the torque–time curves could be used to evaluate not only the variation of the thermooxidative degradation of the PP powder treated under aging conditions before mixing but also the variation of the degradation, including the mechanochemical degradation, of the PP powder during the period of mixing. The dependence of the variation of the degradation of the polymer on the processing time during mixing could be evaluated by the study of the variation of the torque–time curves. It can be concluded that the application of torque–time curves to the evaluation of degradation of PP powder has the advantages of being convenient, real‐time, in situ, online, and production‐oriented. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and characterization of micron‐sized magnetic microspheres by one‐step suspension polymerization
Authors: Liu Zuli , Liu Cuicui , Yao Kailun , Liu Pandong , Ning Qin 
Published: April 2007

AbstractMicron‐sized magnetic microspheres with different functional groups were prepared by one‐step suspension copolymerization of styrene, divinyl benzene, and methyl methacrylate in the presence of oleic acid‐coated magnetic nanoparticles. In the present work, we used benzoyl peroxide as an initiator and poly(vinyl alcohol) (PVA‐1788; degree of polymerization: 1,700; degree of hydrolysis: 88%) as a stabilizer. We also added acrylamide (AM) monomer in the aqueous phase and methacrylic acid (MAA) in the oil phase. The morphology and properties of the resulting magnetic microspheres were examined by optical micrographs (OMs), vibrating‐sample magnetometer (VSM), and Fourier transform infrared spectrometer (FT IR). The results showed the three products have uniform and spherical form with superparamagnetism and well dispersion. Moreover, we found that monomer AM had a little contribution to the copolymerization, and MAA could strikingly decrease the diameter of the final microspheres. The magnetic microspheres with functional groups could be linked well with the IgG‐FITC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of poly(pyridylurea) and poly(pyridylthiourea), potentially semiconducting polymers
Authors: Díaz F. R. , Godoy A. , Moreno J. , Bernède J. C. , Del Valle M. A. , Tagle L. H. , East G. A. 
Published: April 2007

AbstractPoly(pyridylureas) and poly(pyridylthioureas) were synthesized by reacting 2,6‐diaminopyridine with phosgene and thiophosgene, respectively, using THF and pyridine as solvent. The synthesized polymers were characterized by IR‐spectroscopy, elemental analysis, and X‐ray photoelectron spectroscopy. Thermal stability of the polymers was determined by thermal degradation between 35°C and 700°C. The 50% weight loss of polypyridylureas was above 400°C while for the polypyridylthioureas it was above 450°C. Undoped poly(pyridylureas) and poly(pyridylthioureas) behave as semiconductors, σ = 10−9 (Ω cm)−1. After doping with I2 and SbF5, the electrical conductivity increases several orders of magnitude, σ = 10−7(Ω cm)−1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
In situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through an electrospinning process
Authors: Faridi‐Majidi Reza , Sharifi‐Sanjani Naser 
Published: April 2007

AbstractIron oxide nanoparticle coated poly(ethylene oxide) nanofibers as organic–inorganic hybrids with 200–400‐nm diameters were prepared by the in situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through the electrospinning of a poly(ethylene oxide) solution having Fe2+ and Fe3+ ions in a gaseous ammonia atmosphere. Transmission electron microscopy analysis proved the presence of iron oxide nanoparticles on the polymer nanofibers. The thermal properties of the nanofiber mat were also studied with differential scanning calorimetry and thermogravimetric analysis techniques. X‐ray diffraction showed that the formed iron oxide nanoparticles were maghemite nanoparticles. The results were compared with those of the electrospinning of a poly(ethylene oxide) solution having Fe2+ and Fe3+ ions and a pure poly(ethylene oxide) solution in an air atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis, characterization, and thermal stability of azomethine oligomer and its metal complexes
Authors: Kaya İsmet , Bilici Ali 
Published: April 2007

AbstractThe oxidative polycondensation reaction conditions of N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (2‐HNMU) has been accomplished using NaOCl, H2O2, and air O2 oxidants in an aqueous alkaline medium. The structures of the obtained monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13C NMR, and elemental analysis. The characterization was made by TG‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo‐N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (O‐2‐HNMU) was found to be 95% (for air O2 oxidant), 51% (for H2O2 oxidant), 96% (for NaOCl oxidant). According to the SEC analysis, the number‐average molecular weight (Mn), weight‐average molecular weight (Mw), and polydispersity index values of O‐2‐HNMU was found to be 1036, 1225 g/mol, and 1.182, respectively, using H2O2, and 765, 1080 g/mol, and 1.412, respectively, using air O2, and 857, 1105 g/mol, and 1.289, respectively, using NaOCl. TG‐DTA analyses showed that O‐2‐HNMU was more stable than 2‐HNMU. According to TG analyses, the carbonaceous residue of 2‐HNMU and O‐2‐HNMU was found to be 0.49% and 2.11% at 1000°C, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Modification of the physical, mechanical and thermal properties of poly(vinyl chloride) by blending with poly(ethyl methacrylate)
Authors: Chakrabarti Rupa , Chakraborty Debabrata 
Published: April 2007

AbstractBlends of poly(vinyl chloride) (PVC) with different ratio of poly(ethyl methacrylate) were characterized with respect to their physical, mechanical, thermal, and morphological properties. The blends indicated a gradual rise in the modulus and ultimate tensile strength values followed by a reduction in the percent elongation at break and toughness values after an initial rise compared to the base reference compound PVC. The effect of composition of the PVC‐PEMA blends on the thermal stability was investigated. Differential scanning calorimetric curves of the blends showed an inward shift of the PVC glass transition temperature and an upward shift in the degradation temperature. The thermomechanical analysis results also indicated thermal stability over unmodified base reference compound PVC from the softening characteristics of the different samples under study. The biphasic cocontinuous systems as explicit from the scanning electron and optical micrographs supported phase‐mixing at the initial stages with subsequent phasing out tendency with increasing percentage of PEMA incorporation. The thermomechanical parameters are in conformity to their mechanicals, which have been further supported by their morphological studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and characterization of polystyrene modified single‐walled carbon nanotube
Authors: Guojian Wang , Yue Dong , Lin Liu , Caixia Zhao 
Published: April 2007

AbstractA halogen atom terminated Polystyrene (PSt) was prepared by means of atom transfer radical polymerization. Then, the halogen atom was converted into ‐N3 group and a ‐N3 terminated PSt was obtained. Finally PSt was grafted onto the surface of single walled carbon nanotube (SWNT) by the reaction of azide group with SWNT. Comparison of X‐ray photoelectron spectrometer of N1s electron belonging to ‐N3 and the surface of SWNT demonstrated that three‐membered rings were formed by releasing N2 from ‐N3 during the reaction. The structure of PSt modified SWNT was characterized by FTIR, UV, Raman spectrum, and TEM. The experimental results showed that the PSt was connected assuredly to SWNT by the covalent bond. TGA data showed that the amount of PSt on the surface of SWNT firstly increased with growing
$ \overline{M}_n $
of PSt and then decrease when $ \overline{M}_n $
continues to grow. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of soft segment composition on the physical properties of nonionic aqueous polyurethane containing side chain PEGME
Authors: Yen Meng‐Shung , Tsai Hsiang‐Chin , Hong Po‐Da 
Published: April 2007

AbstractIn this study, a series of nonionic waterborne polyurethanes containing side chain poly(ethylene glycol) monomethyl ether (PEGME) were synthesized using 4,4‐methylene bis(isocyanatocyclohexane), the nonionic dispersing center produced by isophorone diisocyanate, N‐diethanol amine, and PEGME, and a series of soft segments [polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), and polycaprolactone (PCL)] with a different molecular weight. The solution properties of the polyurethane (PU) dispersions, thermal properties of the PU casting films, and the water vapor permeability (WVP) of the PU coated fabrics were investigated. Our results show that the surface tension of PU dispersion and its contact angle to untreated nylon fabric are higher for the ether‐based PU dispersion than for the ester‐based PU dispersion, with a sequence of PEG‐PU ≫ PTMG‐PU ≫ PPG‐PU ≫ PCL‐PU. Both the surface tension and the contact angle between PU dispersion and nylon fabric increase upon increasing the Mw of the soft segment. As for the thermal property of PU film, the Tgs of PCL‐PU is the highest, followed by PEG‐PU, PTMG‐PU, and PPG‐PU, and the Tgs decreases with the increase in the length of the soft segment. The Tms follows the order: PEG‐PU ≫ PCL‐PU ≫ PPG‐PU ≫ PTMG‐PU, and the Tms increases upon increasing the soft segment length. As regard to PU coated fabric, the trend of WVP is PEG‐PU ≫ PTMG‐PU ≫ PPG‐PU ≫ PCL‐PU, which increases with the increasing the soft segment length. With regarding to application for the coating, the Coated‐PU with PEG‐PU has an excellent WVP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Properties of poly(urea‐formaldheyde) microcapsules containing an epoxy resin
Authors: Cosco S. , Ambrogi V. , Musto P. , Carfagna C. 
Published: April 2007

AbstractPhysical properties of urea‐formaldehyde microcapsules containing an epoxy resin are presented and discussed. Microcapsules were prepared by in situ polymerization of monomers in an oil‐in‐water emulsion. Differential scanning calorimetry, thermogravimetric analysis, and scanning electronic microscopy were applied to investigate thermal and morphological microcapsule properties. Microencapsulation was detected by means of FTIR and Raman techniques. It was found that the amount of encapsulated epoxy resin as well as the extent of urea‐formaldehyde polymerization depends on the reaction temperature and the stirring speed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis of SBR/PMMA core/shell latices: The role of initiator and surfactant on particle morphology and instability performance
Authors: Moghbeli M. R. , Mohammadi N. , Bagheri R. 
Published: April 2007

AbstractPoly(butadiene‐stat‐styrene)/poly(methylmetacrylate), SBR/PMMA, structural latices were synthesized by using equal moles of different kinds of surfactants: anionic, nonionic, and anionic/nonionic mixture in a two‐stage emulsion polymerization. The results indicate that the application of anionic surfactants for the first stage, accompanying sodium persulfate initiator, KPS, for both stages led to core/shell and raspberry morphologies depended upon the hydrophilic lipophilic balance (HLB) of the surfactant. On the other hand, a core/shell structure was observed for structural latices which were synthesized via application of nonionic or anionic/nonionic mixed surfactants along with azobisisobutyronitrile, AIBN, and KPS as first and second‐stage initiators, respectively. The surface polarity and wettability of the seed particles and finally the tendency of the systems to gain the minimum surface free energy change are the basis for the observed morphologies. On the other hand, the stability of core/shell particles was investigated via incremental addition of an electrolyte, ammonium acetate, at temperature close to the glass transition of PMMA shell, 85°C. The particle size measurement on destabilized samples showed that the core/shell latex only stabilized by anionic surfactant was considerabely microagglomerated with increasing the electrolyte content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Processing of mica/epoxy nanocomposites by ultrasound mixing
Authors: Boukerrou Amar , Duchet Jannick , Fellahi Said , Sautereau Henry 
Published: April 2007

AbstractRubbery mica/epoxy nanocomposites are synthetized by in situ polymerization, and their morphology, mechanical, and viscoelastic properties were investigated by wide angle X‐ray scattering (WAXS), transmission electron microscopy (TEM), tensile testing, and dynamic mechanical thermal analysis (DMTA). Ultrasonicator was used as a means of applying external shearing forces to disperse the silicate clay layers in the epoxy matrix. The first step of the nanocomposite preparation consisted of swelling the mica in a curing agent, i.e., aliphatic diamine based on polyoxypropylene backbone having a low viscosity for better diffusion into the intragalleries. Then, the epoxy prepolymer was added into the mixture. It was expected to have better dispersion and intercalation of the nanoclay in the matrix. The study showed that the organomodification of mica with octadecylammonium ions leads to an increase in the initial d‐spacing ([d001] peak) from 12.3 to 28.1 Å, determined by WAXS, indicating the occurrence of an intercalation. The addition of 5 per hundred resin (phr) of MICAC18 into the epoxy matrix resulted in finer dispersion as evidenced by both the disappearance of the diffraction peak in the WAXS pattern and TEM images. The mechanical and viscoelastic properties were improved for both MICA and MICAC18 nanocomposites, however, more pronounced for the modified ones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007