bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of degradation on Nylon‐6 and Nylon‐6/montmorillonite nanocomposite by color measurement
Authors: Ito Mikiya , Nagai Kazukiyo 
Published: March 2008

AbstractAn evaluation of degraded level is an important subject for industrial products. Ordinarily, many kinds of polymer material changes its color through the degrading process by altering its chemical structure, and IR and UV are applicable to ensure the production of the functional groups. However, these methods are hardly applicable to measurements of product on site without the sample collection. A spectrophotometer is sufficiently lightweight, compact, and capable of measurements on site without the sample collection. With these backgrounds, the correlation of the color with the tensile strength and the molecular weight was studied by using the spectrophotometer. Through the thermal aging test at various temperatures, specimens became yellowish and the increase rate of color change was different between neat Nylon‐6 and Nylon‐6 nanocomposite. Such changes were closely related to the tensile strength and the molecular weight. As a method to evaluate the polymer degradation, the correlation of the difference of yellowness index (ΔYI) with the tensile strength and the molecular weight was sufficiently high and the ΔYI indicated a difference between neat Nylon‐6 and Nylon‐6 nanocomposite. From these results, it is found that the color measurement with the spectrophotometer is a practical method for evaluation of polymer degradation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Toughening effect of EPDM‐graft‐methyl methacrylate and styrene (EPDM‐g‐MMA‐St) on methyl methacrylate‐styrene copolymer (MS resin)
Authors: Fu Jinfeng , Wang Lianshi , Zhang Anqiang 
Published: March 2008

AbstractEPDM‐graft‐methyl methacrylate and styrene (EPDM‐g‐MMA‐St) was synthesized by solution graft copolymerization of methyl methacrylate (MMA) and styrene(St) onto ethylene‐proplene‐diene terpolymer (EPDM) in toluene/n‐heptane cosolvent using benzoyl peroxide as an initiator. Fourier transform infrared spectroscopy provides a substantial evidence of grafting of MMA and St onto EPDM. EPDM‐g‐MMA‐St/MS resin blends (MES) were prepared by melt blending EPDM‐g‐MMA‐St and MS resin, and the toughening effects of EPDM‐g‐MMA‐St on MS resin were studied. The results showed that the synthesized conditions of EPDM‐g‐MMA‐St influenced the toughening effect of EPDM‐g‐MMA‐St on MS resin. Notched Izod impact strength of MES increased with increasing grafting ratio, grafting chain polarity of EPDM‐g‐MMA‐St, and EPDM content in MES. Differential scanning calorimetry showed that EPDM‐g‐MMA‐St and MS resin are compatible partially and the compatibility improves with increasing grafting chain polarity of EPDM‐g‐MMA‐St. Transmission electron microscopy and scanning electron microscopy analysis showed that the phase structure was “sea‐island” structure, and the particle diameter of EPDM‐g‐MMA‐St increased, meanwhile, surface to surface interparticle distance decreased with an increase in EPDM content, which resulted in the toughening mechanism of MES changed into slight shear yielding of matrix from the damage mode of cavitation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Molecular relaxation behavior of fatty acid‐based vinyl ester resins
Authors: Boyd Steven E. , La Scala John J. , Palmese Guiseppe R. 
Published: March 2008

AbstractThe experimental characterization of the time‐dependent properties of fatty acid‐based vinyl ester resins with reduced styrene content and emissions was conducted and compared with that of various commercial vinyl ester (VE) resins. Constant heating rate and isothermal, multifrequency sweep experiments were conducted over a wide temperature range using dynamic mechanical analysis. Storage and loss modulus master‐curves were formed using time–temperature superposition (TTSP) and analyzed to quantify the molecular relaxation behavior using accepted techniques and theories. Special attention was focused on determining the effect of reducing styrene weight percent on the derived viscoelastic properties. The fatty acid‐based VE resins were found to have similar or slightly inferior thermomechanical properties and a more pronounced viscoelastic response compared with the commercial resins. However, the research definitively demonstrates that the evaluated fatty acid VE resins are a viable replacement to commercial resins in certain applications with concomitant attractive environmental benefits. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Ethylene homo‐ and copolymerization over MgCl2‐TiCl4 catalysts: Polymerization kinetics and polymer particle morphology
Authors: Hassan Nejad Mehdi , Ferrari Paolo , Pennini Gianni , Cecchin Giuliano 
Published: March 2008

AbstractThree procatalysts of the MgCl2/TiCl4 type, differing mainly in their morphological characteristics, were investigated in ethylene polymerization and ethylene‐1‐butene copolymerization. Apparently, hydrogen has an intrinsic and general deactivating effect but it can also play an activating effect in homopolymerization. This peculiarity was found to be related to a catastrophic breakage of the polymer/catalyst particles during growth and thus to the exposure of new active centers. In this case the kinetic profiles are irregular and characterized by one or more secondary peaks which reflect the moment when this morphology‐driven rate‐enhancement effect takes place. In general, the prepolymerization of the procatalysts with propylene tends to slightly enhance homopolymerization rate, to slow down copolymerization rate and to stabilize the morphology of the growing polymer particles, thus preventing the occurrence of the irregular kinetic profiles observed during homopolymerization in the presence of hydrogen. The behavior of the procatalysts investigated was found to depend on the distribution of their pore size rather than the absolute values of their porosity. Likely this is due to an easier diffusion of the monomer and a more regular and homogeneous growth of the polymer within larger as opposed to smaller pores. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Melting behavior, isothermal and nonisothermal crystallization kinetics of EPPE/mLLDPE blends
Authors: Qin Jianglei , Deng Kuilin , Li Zhiting 
Published: March 2008

AbstractMelting behavior and crystallization kinetics of easy processing polyethylene (EPPE) and the blends of EPPE/mLLDPE were studied using differential scanning calorimetry at various crystallization temperature and cooling rates. The Avrami analysis was employed to describe the isothermal and nonisothermal crystallization process of pure polymers and their blends, and a method developed by Mo was applied for comparison. Kinetic parameters such as the Avrami exponent (n), the kinetic crystallization rate constant (k and kc), the peak temperatures (Tp), and the half‐time of crystallization (t1/2), etc. were determined. The appearance of double melting peaks and the double crystallization peaks of the polymers showed that the main chain and the branches crystallize seperately, but the main chains of two polymers can crystallize together and mLLDPE act as nuclei while EPPE crystallizes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Spectral characterization of lysozyme adsorption on dye‐affinity beads
Authors: Basar Nilgün , Uzun Lokman , Güner Ali , Denizli Adil 
Published: March 2008

AbstractCibacron Blue F3GA‐attached magnetic poly(2‐hydroxyethyl methacrylate) [mPHEMA] beads were prepared by suspension polymerization of HEMA in the presence of magnetite (Fe3O4) nanopowder. Average diameter size of the mPHEMA beads was 150–200 μm. The characteristic functional groups of Cibacron Blue F3GA‐attached mPHEMA beads were analyzed by Fourier transform infrared spectrometer (FTIR) and Raman scattering spectrometer. The lysozyme adsorption and desorption characteristics of Cibacron Blue F3GA‐attached mPHEMA beads were also investigated using FTIR and Raman spectroscopic techniques. When the Raman spectrum of lysozyme adsorbed mPHEMA is evaluated characteristic Amide‐I band appears at 1657 cm−1. The intensity of this band decreases in the spectrum of lysozyme desorbed mPHEMA sample. When the characteristic bands of lysozyme adsorbed and desorbed mPHEMA samples are compared, the band intensities of desorbed sample are lower than those of lysozyme adsorbed sample except for the band appearing at 656 cm−1 (Tyr vCS). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of silane and MAPE coupling agents on the properties and interfacial adhesion of wood‐filled PVC/LDPE blend
Authors: Prachayawarakorn J. , Khunsumled S. , Thongpin C. , Kositchaiyong A. , Sombatsompop N. 
Published: March 2008

AbstractComposite samples were prepared from Poly(vinyl chloride)/low‐density polyethylene (PVC/LDPE) blend, compatibilized by PA20 (methyl methacrylate‐co‐butyl acrylate copolymer), and reinforced by different levels of rubber‐wood sawdust. To improve the mechanical properties of the composites, Silane A‐137 (Octyltriethoxy silane), Silane A‐1100 (γ‐aminopropyltriethoxy silane), or MAPE (maleic anhydride‐grafted‐polyethylene) were introduced. It was found that the additions of Silane A‐137, Silane A‐1100, and MAPE could improve tensile and impact properties of the composites, regardless of the sawdust contents. Physical or chemical interactions for all coupling agents with the wood‐PVC/LDPE composites used were proposed in this work. Silane A‐137 or MAPE tended to give better improvement in the mechanical properties of the composites than Silane A‐1100, because of the presence of the nonpolar chain ends of Silane A‐137 or MAPE molecules. Besides, the addition of either Silane A‐137 and MAPE or Silane A‐1100 and MAPE at different ratios into the wood‐PVC/LDPE composites was also studied. The experimental results suggested that the optimum mechanical properties could be obtained using Silane A‐137 : MAPE of 1% : 2% wt sawdust. The morphological and thermal properties of the composites were also examined using SEM and DMA techniques, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and properties of tung oil‐based composites using spent germ as a natural filler
Authors: Pfister Daniel P. , Baker Jeffrey R. , Henna Phillip H. , Lu Yongshang , Larock Richard C. 
Published: March 2008

AbstractNovel biocomposites have been prepared by the free radical polymerization of a tung oil‐based resin using spent germ, the coproduct of wet mill ethanol production, as a filler. The effect of filler particle size, amount of filler, amount of crosslinker, and molding pressure on the resulting composites has been investigated. When compared to the pure resin, an increase in storage modulus is observed when filler is added to the matrix. The thermal stabilities of the resulting composites lie between the stabilities of the resin and the spent germ. Decreasing the particle size results in an increase in both the storage modulus and the mechanical properties of the composites. As the amount of crosslinker, divinylbenzene, increases, an improvement in the thermal stabilities and mechanical properties is observed. The composites prepared are mainly composed of renewable resources, possess good thermal and mechanical properties, and have potential applications in the construction and automotive industries. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Conducting polymer blends prepared from polyaniline with n‐dodecylbenzenesulfonic acid zinc salt as the secondary dopant
Authors: Chao Liang , Han Yu‐Kai , Hiseh Bi‐Zen , Huang Ying‐Jie , Hsieh Tar‐Hwa , Lin Ching‐Mao , Lin Shih‐Zen , Tseng Po‐Hao , Ho Ko‐Shan 
Published: March 2008

AbstractA red‐shift of the UV–vis spectra of n‐dodecylbenzenesulfonic acid doped polyaniline (PANI (DBSA)0.5), resulting from the secondary doping of polyaniline backbones, was found in the presence of n‐dodecylbenzenesulfonic acid zinc salt (Zn(DBS)2). It is proved to behave as steric hindrance spacers to induce the extension of the conjugation length through the straightening effect on the polyaniline backbones and the obtained mixtures (PANI(DBSA)0.5 plus Zn(DBS)2) can be used as master batch materials (MB‐13) for blending with regular polypropylene polymer (PP). The thermal degradation accompanied with loss of conductivity for MB‐13 can be delayed to over 250°C when enough Zn(DBS)2 was secondarily doped on PANI(DBSA)0.5., which allow the performance of its blending with other nonconducting/regular polymers possible. Below 80 rpm, increasing shear rates would induce higher viscosity difference between the MB‐13 and PP matrix, resulting in elongation of MB‐13 in the PP matrix and higher conductivities of the polyblends. The deviation from the Taylor equation, which is used to estimate the degree of elongation for a polyblend, started when shear rate is over 80 rpm. The leakage of Zn(DBS)2 out of MB‐13 can be confirmed by comparing the DSC thermograms and X‐ray diffraction patterns with that of neat PP. Gradual deformation for the conductive fillers (MB‐13) and a well‐defined and expanded layered structure can be found when processing time is below 15 min with 60 rpm shear rate. The layers started to shrink back after 15 min of procession with the loss of the Zn(DBS)2 from MB‐13 in the PP matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Molecular dynamics simulations on the blends of poly(vinyl pyrrolidone) and poly(bisphenol‐A‐ether sulfone)
Authors: Jawalkar S. S. , Nataraj S. K. , Raghu A. V. , Aminabhavi T. M. 
Published: March 2008

AbstractMolecular simulations are the most important tools to predict the properties of polymers and their blends. In this work, we have predicted the blend incompatibility of poly(n‐vinyl pyrrolidone) (PVP) and poly(bisphenol‐A‐ether sulfone) (PES). Atomistic simulations were performed to compute the Flory‐Higgins interaction parameter over all the compositions ranging from 90 to 10% of the individual polymers, which confirmed that the blends are incompatible (Bhattacharya et al., J Membr Sci 2003, 227, 23). Kinetics of phase separation was examined via density profiles calculated using MesoDyn approach. For incompatible blends, the critical value of 0.32 computed from the Flory‐Huggins theory agreed with the value of 0.29, suggesting the validity of our approach. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Interfacial structure of poly(methyl methacrylate)/TiO2 nanocomposites prepared through photocatalytic polymerization
Authors: Wang Jiao , Ni Xiuyuan 
Published: March 2008

AbstractPoly(methyl methacrylate)/TiO2 nanocomposites have been prepared by the polymerization with photoexcited TiO2 nanoparticles as initiator. To reveal the interfacial structure, the composites obtained are investigated by FTIR and XPS analysis. The bound PMMA displays triply split IR bands attributed to the carbonyl stretching mode, meanwhile great changes also occur in the IR range closely related to the conformation of PMMA. Based on the area of the nonassociated and associated PMMA carbonyl stretching peaks in the FTIR spectrum, it is calculated out that the bound PMMA is constituted of 70% repeating units in nonassociated state and 30% units associated to TiO2 inorganic nanoparticles. Moreover, XPS analysis show that Ti2p doublet of the composites shift to lower binding energy by 1.0 eV, indicating the interaction between Ti atoms of TiO2 and oxygen atoms of PMMA. According to the observation that the interaction involves both carboxyl and carbonyl groups of PMMA, a bidentate complex is approved. In addition, compared with the extracted PMMA, certain backbone chains of bound PMMA have to change their rotational conformations from gauche to trans so as to bond to the surface active centers at TiO2 nanoparticles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Melt rheological properties of reactive compatibilized HDPE/PET blends
Authors: Li Shu‐Cai , Lu Li‐Nong 
Published: March 2008

AbstractMelt rheological properties of high density polyethylene and poly(ethylene terephthalate) (HDPE/PET) blends compatibilized by an ethylene–butyl acrylate–glycidyl methacrylate terpolymer (EBAGMA) were studied by means of a HAAKE torque rheometer and a capillary rheometer. The phase morphology of the blends was evaluated by a scanning electron microscope (SEM). The results showed that the melts of blends behave pseudoplasticity. The addition of EBAGMA strengthens the interfacial adhesion between HDPE and PET and improves the phase dispersion due to reactive compatibilization. It was observed that the balance torque, melt viscosity, and sensitivity of melt viscosity to shear rate of the melts increase with increasing content of EBAGMA, but the melt flow index and activation energy decrease. At the same time, the plasticizing time is shortened indicating that the processability of the compatibilized blends has been improved. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of molecular weight distribution on flow properties of commercial polyolefins
Authors: Zahedi Mostafa , Ahmadi Mostafa , Nekoomanesh Mehdi 
Published: March 2008

AbstractThe aim of this work is to investigate the effects of molecular weight distribution on some conventional flow properties of polyolefins like melt flow index, melt flow ratio, and power law index. The study is designed in two steps. First, the statistical correlation analysis was carried out for proper choice of input variables for each output property and to find the most relevant mathematical forms of the considered parameters for the modeling section. Then the considered property was correlated to the entire molecular weight distribution using spline functions. The best fit was achieved by variation of the number of spline nodes and their values. The proposed methodology is able to be coupled with a polymerization model to correlate the polymerization conditions to the final properties of the product and design a polymerization control loop. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Response error and processing biases in confidence judgment
Authors: Merkle Edgar C. , Sieck Winston R. , van Zandt Trisha 
Published: March 2008

AbstractPrevious studies showed that random error can explain overconfidence effects typically observed in the literature. One of these studies concluded that, after accounting for random error effects in the data, there is little support for cognitive‐processing biases in confidence elicitation. In this paper, we investigate more closely the random error explanation for overconfidence. We generated data from four models of confidence and then estimated the magnitude of random error in the data. Our results show that, in addition to the true magnitude of random error specified in the simulations, the error estimates are influenced by important cognitive‐processing biases in the confidence elicitation process. We found that random error in the response process can account for the degree of overconfidence found in calibration studies, even when that overconfidence is actually caused by other factors. Thus, the error models say little about whether cognitive biases are present in the confidence elicitation process. Copyright © 2008 John Wiley & Sons, Ltd.
Hybrid treatment of a symptomatic popliteal pseudoaneurysm due to type‐I endoleak after previous endovascular exclusion
Authors: de Koning Heleen D. , Zeebregts Clark J. , Reijnen Michel M.P.J. 
Published: March 2008

AbstractPurpose: The development of endovascular repair of popliteal aneurysms has provided an alternative, minimally invasive way of treatment. We present a case of a late type‐I endoleak, after previous exclusion of a popliteal pseudoaneurysm, leading to rupture and massive hematoma, which was excluded in a hybrid procedure. Case Report: A 95‐year‐old woman presented with progressive swelling with skin ulceration and necrosis cranial to the medial side of her left knee. Four years earlier, a left popliteal pseudoaneurysm was excluded with a stent‐graft. Rupture of the popliteal artery with massive hematoma was demonstrated by ultrasound examination and a spiral computed tomography scan, with high suspicion of a type‐I endoleak. Endovascular repair of the endoleak with a polytetrafluoroethylene‐covered stent‐graft was followed by surgical resection of the damaged skin and evacuation of the hematoma. Conclusion: Type‐I endoleaks after endovascular exclusion of popliteal pseudoaneurysms do occur and may lead to rupture. A symptomatic pseudoaneurysm may be successfully treated by a hybrid procedure. © 2008 Wiley‐Liss, Inc.
A novel approach for quantitative analysis of intracoronary optical coherence tomography: High inter‐observer agreement with computer‐assisted contour detection
Authors: Tanimoto Shuzou , Rodriguez‐Granillo Gaston , Barlis Peter , de Winter Sebastiaan , Bruining Nico , Hamers Ronald , Knappen Michiel , Verheye Stefan , Serruys Patrick W , Regar Evelyn 
Published: March 2008

AbstractObjective: This study aims to examine observer‐related variability of quantitative optical coherence tomography (OCT) derived measurements from both in vitro and in vivo pullback data. Background: Intravascular OCT is a new imaging modality using infrared light and offering 10 times higher image resolution (15 μm) compared to intravascular ultrasound. The quantitative analysis of in vivo intracoronary OCT imaging is complicated by the presence of blood, motion artifacts and the large quantity of information that has to be processed. Methods: We developed a standardized, automated quantification process for intracoronary OCT pullback data with inter‐observer variability assessed both in vitro by using postmortem human coronary arteries and in vivo by studying simple and complex coronary pathology and outcomes following stent implantation. The consensus between measurements by two observers was analyzed using the intraclass and interclass correlation coefficient and the reliability coefficients. Bland–Altman plots were generated to assess the relationship between variability and absolute measurements. Results: In vitro OCT assessment was performed in nine postmortem coronary arteries. The time needed for semiautomated contour detection of a 15‐mm long coronary segment was ∼40 min. The absolute and relative difference between lumen area measurements derived from two observers was low [0.02 ± 0.10 mm2; (0.3 ± 0.5)% respectively] with excellent correlation confirmed by linear regression analysis (R2 = 0.99; P < 0.001). Similarly, in vivo measurements demonstrated a high correlation with the main source of inter‐observer variation occurring as a result of coronary dissection and motion artifact. The absolute and relative difference between measurements were 0.11 ± 0.33 mm2 (1.57 ± 0.05)% for lumen area (R2 = 0.98; P < 0.001), 0.17 ± 0.68 mm2 (1.44 ± 0.08)% for stent area (R2 = 0.94; P < 0.001), and 0.26 ± 0.72 mm2 (14.08 ± 0.37)% for neointimal area (R2 = 0.78; P < 0.001). Conclusions: Highly accurate computer‐assisted quantitative analysis ofintracoronary OCT pullbacks is feasible with low inter‐observer variability. The presented approach allows for observer independent analysis of detailed vessel structures, and may be a valuable tool for future longitudinal studies incorporating OCT. © 2008 Wiley‐Liss, Inc.