bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(vinyl chloride) hollow‐fiber membranes for ultrafiltration applications: Effects of the internal coagulant composition
Authors: Alsalhy Qusay F. , Rashid Khalid T. , Noori Wallaă A. , Simone S. , Figoli A. , Drioli E. 
Published: October 2011

AbstractPoly(vinyl chloride) (PVC) hollow‐fiber membranes were spun by a dry/wet phase‐inversion technique from dopes containing 15 wt % PVC to achieve membranes with different pore sizes for ultrafiltration (UF) applications. The effects of the N,N‐dimethylacetamide (DMAc) concentration in the internal coagulant on the structural morphology, separation performance, and mechanical properties of the produced PVC hollow fibers were investigated. The PVC membranes were characterized by scanning electron microscopy, average pore size, pore size distribution, void volume fraction measurements, and solubility parameter difference. Moreover, the UF experiments were conducted with pure water and aqueous solutions of poly(vinyl pyrrolidone) as feeds. The mechanical properties of the PVC hollow‐fiber membranes were discussed in terms of the tensile strength and Young's modulus. It was found that the PVC membrane morphology changed from thin, fingerlike macrovoids at the inner edge to fully spongelike structure with DMAc concentration in the internal coagulant. The effective pores showed a wide distribution, between 0.2 and 1.1 μm, for the membranes prepared with H2O as the internal coagulant and a narrow distribution, between 0.114 and 0.135 μm, with 50 wt % DMAc. The results illustrate that the difference in the membrane performances was dependent on the DMAc concentration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Chemical interaction between carbon fibers and surface sizing
Authors: Dai Zhishuang , Zhang Baoyan , Shi Fenghui , Li Min , Zhang Zuoguang , Gu Yizhuo 
Published: October 2011

AbstractFunctional groups on the surface of Polyacrylonitrile (PAN)‐based carbon fibers and in fiber surface sizing are likely to react during the curing process of composites, and these reactions could affect the infiltration and adhesion between the carbon fibers and resin. T300B‐3000‐40B fibers and fiber surface sizing were heat‐treated at different temperatures, and the structural changes of both the fiber surface sizing and extracted sizing after heat treatment were investigated by Fourier transform infrared spectroscopy. The results show that the concentration of epoxy groups in both the fiber surface sizing and extracted sizing decreased with increasing heat‐treatment temperature and decreased to zero after treatment at 200°C. The concentration of epoxy groups in the extracted sizing was lower than that of the fiber surface sizing after treatment under the same conditions; this indicated that the rate of reaction between the carbon fibers and fiber surface sizing was higher than the reaction rate of the fiber surface sizing system. X‐ray photoelectron spectroscopy analysis reveals that the content of CO bonds and activated carbon atoms on the surface of the desized treated carbon fibers was the highest when the heat‐treatment temperature was 150°C; this proved the reaction between the carbon fibers and the fiber surface sizing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Atom transfer radical copolymerization of glycidyl methacrylate and methyl methacrylate
Authors: Neugebauer Dorota , Bury Katarzyna , Wlazło Michał 
Published: October 2011

AbstractGlycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (rGMA = 1.24 ± 0.02 and rMMA = 0.85 ± 0.03) and by the Mayo–Lewis method (rGMA = 1.19 ± 0.04 and rMMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by 1H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (Tg) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and anticoagulant activity of pectin sulfates
Authors: Fan Lihong , Gao Song , Wang Libo , Wu Penghui , Cao Mi , Zheng Hua , Xie Weiguo , Zhou Jinping 
Published: October 2011

AbstractIn this article, we describe the first use of trisulfonated sodium amine as a sulfating reagent for preparing pectin sulfate in aqueous solution. The main reaction parameters that were expected to affect the degree of substitution (DS) were studied. The optimal reaction conditions for the synthesis of pectin sulfate were found to be as follows: the pH of the reaction medium, the reaction temperature, the reaction time, and the ratio of the mole of sodium nitrite (nNaNO2) to the mass of pectin (mpectin) were 6, 60°C, 12 h, and 2.5/190 mol/g, respectively. Pectin and pectin sulfate were characterized by Fourier transform infrared (FTIR) spectroscopy and 13C‐NMR. The FTIR spectra showed the characteristic absorptions of sulfate ester bonds at 1264 and 830 cm−1. Furthermore, the anticoagulant activity of pectin sulfates with different DSs, concentrations, and molecular weights were investigated with respect to the activated partial thromboplastin time (APTT), thrombin time (TT) and prothombin time. The clotting assay indicated that the pectin sulfate prolonged APTT and TT through inhibition of the activity of antithrombin. These results suggest that the introduction of sulfate groups into the pectin structure improved its anticoagulant activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of crosslinked polyacrylonitrile via atom transfer radical polymerization with activators regenerated by electron transfer and use of the resin in mercury removal after modification
Authors: Zong Guangxi , Ma Jing , Chen Hou , Wang Chunhua , Ji Naiyi , Liu Delong 
Published: October 2011

AbstractCrosslinked polyacrylonitrile (PAN) was synthesized with divinylbenzene as the crosslinker with an iron(III)‐mediated atom transfer radical polymerization method with activators regenerated by electron transfer. The polymerization exhibited first‐order kinetics with respect to the polymerization time. Hydroxylamine hydrochloride (NH2OH·HCl) was used to modify the cyano groups of the crosslinked PAN to obtain amidoxime (AO) groups. The AO‐crosslinked PAN was used to remove Hg(II). The optimum pH, adsorption kinetics, and adsorption isotherms were investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fractional thermoelectric viscoelastic materials
Authors: Ezzat Magdy A. , El‐Karamany Ahmed S. 
Published: October 2011

AbstractA new mathematical model of thermoelectro viscoelasticity theory was constructed in the context of a new consideration of heat conduction with fractional order. The state space approach developed earlier by Ezzat was adopted for the solution of a one‐dimensional problem in the presence of heat sources. The Laplace‐transform technique was used. A numerical method was employed for the inversion of the Laplace transforms. According to the numerical results and their graphs, a conclusion about the new theory was constructed. Some comparisons are shown in figures to estimate the effect of the fractional order parameter on all of the studied fields. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Crystallization kinetics of poly (L‐lactic acid)/montmorillonite nanocomposites under isothermal crystallization condition
Authors: Hwang Jiunn‐Jer , Huang Su‐Mei , Liu Hsin‐Jiant , Chu Hawn‐Chung , Lin Li‐Huei , Chung Chen‐Sheng 
Published: October 2011

AbstractPoly(L‐lactic acid)/o‐MMT nanocomposites, incorporating various amounts of organically modified montmorillonite (o‐MMT; 0–10 wt %), were prepared by solution intercalation. The montmorillonite (MMT) was organically modified with dilauryl dimethyl ammonium bromide (DDAB) by ion exchange. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) reveal that the o‐MMT was exfoliated in a poly(L‐lactic acid), (PLLA) matrix. A series of the test specimens were prepared and subjected to isothermal crystallization at various temperatures (T1–T5). The DSC plots revealed that the PLLA/o‐MMT nanocomposites that were prepared under nonisothermal conditions exhibited an obvious crystallization peak and recrystallization, but neat PLLA exhibited neither. The PLLA/o‐MMT nanocomposites (2–10 wt %) yielded two endothermic peaks only under isothermal conditions at low temperature (T1), and the intensity of Tm2 (the higher melting point) was proportional to the o‐MMT content (at around 171°C). The melting point of the test samples increased with the isothermal crystallization temperature. In the Avrami equation, the constant of the crystallization rate (k) was inversely proportional to the isothermal crystallization temperature and increased with the o‐MMT content, especially at low temperature (T1). The Avrami exponent (n) of the PLLA/o‐MMT nanocomposites (4–10 wt %) was 2.61–3.56 higher than that of neat PLLA, 2.10–2.56, revealing that crystallization occurred in three dimensions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of clay‐dispersed poly(styrene‐co‐methyl methacrylate) nanocomposite via miniemulsion atom transfer radical polymerization: A reverse approach
Authors: Khezri Khezrollah , Haddadi‐Asl Vahid , Roghani‐Mamaqani Hossein , Salami‐Kalajahi Mehdi 
Published: October 2011

AbstractPoly(styrene‐co‐methyl methacrylate) nanocomposites were synthesized using reverse atom transfer radical polymerization (RATRP) in miniemulsion. Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant applicable at higher temperatures was used for miniemulsion stabilization. Successful RATRP was carried out by using 4,4′‐dinonyl‐2,2′‐bipyridine (dNbPy) as ligand. Monodispersed droplets and particles with sizes in the range of 200 nm were revealed by dynamic light scattering (DLS). Conversion and molecular weight study was carried out using gravimetry and size exclusion chromatography (SEC) respectively. By adding clay content, a decrease in the conversion and molecular weight and an increase in the PDI value of the nanocomposites are observed. Thermal stability of the nanocomposites in comparison with the neat copolymer is revealed by thermogravimetric analysis (TGA). Increased Tg values by adding clay content was also obtained using differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) images of the nanoconposite with 1 wt % of nanoclay loading, display monodispersed spherical particles with sizes in the range of ∼ 200 nm. SEM findings are more compiled with dynamic light scattering (DLS) results. Well‐dispersed exfoliated clay layers in the polymer matrix of the nanocomposite with 1 wt % nanoclay loading is confirmed by transmission electron microscopy (TEM) images and X‐ray diffraction (XRD) data. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of poly(N‐isopropylacrylamide) under atmospheric pressure plasma conditions
Authors: Spridon Delia , Curecheriu Lavinia , Dobromir Marius , Dumitrascu Nicoleta 
Published: October 2011

AbstractThis work is focused on obtaining and characterizing thin films of a certain thermosensitive polymer, i.e., poly(N‐isopropylacrylamide). To obtain such polymers dielectric barrier discharge plasma working at atmospheric pressure in plan–plan geometry was used. The plasma parameters were monitored during polymerization reaction by its electrical and optical signals. The obtained films were analyzed by different techniques such as X‐photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, contact angle, impedance spectroscopy measurements, and light interferometry for thickness measurements. Chemical analyses of obtained films showed that they sort well with the polymers obtained by other methods in literature. It has been proved that plasma polymerized films have a superhydrophilic character at room temperature, the measured contact angle being around 13°, the lower critical solution temperature was also identified at about 30–31°C. The films' thickness for a 10‐min duration deposition was 400 nm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Production of melamine fortified urea‐formaldehyde resins with low formaldehyde emission
Authors: Paiva Nádia T. , Henriques Ana , Cruz Paulo , Ferra João M. , Carvalho Luisa H. , Magalhães Fernão D. 
Published: October 2011

AbstractMelamine can be incorporated in the synthesis of urea‐formaldehyde (UF) resins to improve performance in particleboards (PB), mostly in terms of hydrolysis resistance and formaldehyde emission. In this work, melamine‐fortified UF resins were synthesized using a strong acid process. The best step for melamine addition and the effect of the reaction pH on the resin characteristics and performance were evaluated. Results showed that melamine incorporation is more effective when added on the initial acidic stage. The condensation reaction pH has a significant effect on the synthesis process. A pH below 3.0 results on a very fast reaction that is difficult to control. On the other hand, with pH values above 5.0, the condensation reaction becomes excessively slow. PBs panels produced with resins synthesized with a condensation pH between 4.5 and 4.7 showed good overall performance, both in terms of internal bond strength and formaldehyde emissions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of an amphoteric copolymer on the properties of cementitious materials
Authors: Sheen Yeong‐Nain , Ho Chung‐Da , Weng Wei‐Hung , Hsu Kung‐Chung 
Published: October 2011

AbstractThe effects of an amphoteric copolymer, poly(acrylamide‐co‐(2‐(3‐carboxyacryloyloxy)‐N‐(carboxymethyl)‐N,N‐dimethyl‐ethanaminium) (PAC) on the properties of cement pastes or mortars were investigated. PAC was prepared from acrylamide and 2‐(3‐carboxy‐acryloyloxy)‐N‐(carboxymethyl)‐N,N‐dimethylethanaminium (CAC) through free radical polymerization. The results indicate that the presence of the polymer delayed the setting of cement pastes; it also reduced the water demand so that the resulting mortars showed improved compressive strength and reduced length change. PAC with about 16.7% CAC and a weight‐average molecular weight of about 5 × 104 was effective in promoting the material properties of mortars. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electro‐optical properties of polymer‐dispersed liquid crystal prepared by controlled graft living radical polymerization
Authors: Qin Ailin , Zhang Yuliang , Wang Yinghan 
Published: October 2011

AbstractLiving graft macromolecule has been prepared through reversible addition‐fragmentation chain transfer (RAFT) living radical polymerization in one step. Then, it was used to make polymer‐dispersed liquid crystal (PDLC) by controlling the mole ratio of styrene (St) to 1,6‐hexanediol diacrylate (HDDA) and adjusting the content of prepared graft macromolecule. The results showed that electro‐optical properties of PDLC have been optimized. Different concentration of living graft macromolecule and different mole ratio of St/HDDA led to substantial improvement of driving voltage (threshold voltage and saturation voltage) and memory effect of PDLC simultaneously. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal aging on mechanical properties and crosslinked network of natural rubber/zinc Dimethacrylate composites
Authors: Xu Chuanhui , Chen Yukun , Huang Jing , Zeng Xingrong , Ding Jianping 
Published: October 2011

AbstractThis article dealt with the relationship between mechanical properties and crosslinked networks of natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) after thermal aging. After thermal aging at the present experimental conditions, the covalent crosslink density showed a decrease all the time, whereas the ionic crosslink density was stable at 80°C but decreased at a higher temperature. The decrease in the total crosslink density after aging indicates the degradation of the crosslinked network. However, an experimental phenomenon observed was that the tensile strength and tear strength increased in a certain degree after aging at 80°C or at a 100°C for a short time. In addition, the thermal stability of the NR/ZDMA composite was evaluated by thermal gravimetric analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mixtures of poly(vinyl chloride) and copolyesters based on ε‐caprolactone and L‐lactide: Miscibility, thermal stability, and weathering resistance
Authors: Brožek Jiří , Žídková Markéta , Malinová Lenka , Kalousková Radka 
Published: October 2011

AbstractProperties of the blends of Poly(vinyl chloride) (PVC) and poly(ε‐caprolactone) (PCLO) and copolyesters based on ε‐caprolactone and L‐lactide (LLA) prepared by rolling were studied. Incorporating the LLA units into the structure of PCLO the content of the crystalline phase was controlled. Miscibility of the blends was assessed using DMA, and basic mechanical properties were correlated with the type and content of the polymer plasticizer. The PVC blends containing up to 20 wt parts polyesters were miscible. The presence of the LLA units in the copolyester influenced negatively the thermal stability. On the other hand even small content of copolyester in the blend enhanced the resistivity against aging. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Solvent‐free diazotization–azidation of aryl amine using a polymer‐supported azide ion
Authors: Karimi Zarchi Mohammad Ali , Nabaei Rahman 
Published: October 2011

AbstractCrosslinked poly (4‐vinylpyridine)‐supported azide ion was used as an effective azidating agent for deazodination of stable arenediazonium salts under solvent‐free conditions in high yields. The diazotization of aromatic amines was prepared by grinding the combination of an aromatic amine, sodium nitrite (NaNO2), p‐toluene sulfonic acid (p‐TsOH), and 0.2 mL H2O in a mortar. Grinding was continued for deazodination–azidation of the obtained relatively stable diazonium salts, with addition of crosslinked poly (4‐vinylpyridine) supported azide ion to obtain the corresponding aryl azides. The spent polymeric reagents can usually be removed and regenerated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of the compatibilizer on the morphology and properties of dynamically cured PP/POE/epoxy blends
Authors: Jiang Xue Liang , Fan Yihong 
Published: October 2011

AbstractDynamic vulcanization was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene‐octene copolymer (POE) blends, and the effects of different compatibilizers on the morphology and properties of dynamically cured PP/POE/epoxy blends were studied. The results show that dynamically cured PP/POE/epoxy blends compatibilized with maleic anhydride‐grafted polypropylene (MAH‐g‐PP) have a three‐phase structure consisting of POE and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride‐grafted POE (MAH‐g‐POE) as a compatibilizer, the structure of the core‐shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH‐g‐POE in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilized with MAH‐g‐PP were more efficient nucleating agents for PP than they were in the blends compatibilized with MAH‐g‐POE. WAXD analysis shows that compatibilization do not disturb the crystalline structure of PP in the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of curing temperature on properties and solvent welding strength of ovalbumin
Authors: Lin Yi‐chuan , Chang Z. C. , Lin C. B. , Shen Chien‐Chin , Su Yen‐Li 
Published: October 2011

AbstractEffect of curing temperature on properties of ovalbumin has been investigated. Functional basis, crosslinking degree, tensile strength, and hardness increases with rising curing temperature. The increase of visible transmittance and the decrease of absorption accompany with increasing wavelength. The absorptive peak shows at 440–450 nm and the wavelength of the absorptive peak increases with the rising curing temperature. The relationship of joint strength with solvent welded joints of ovalbumin to their microstructure is also investigated. Ovalbumin can promote joint strength after the treatment of distilled water and curing. Comparing joint strength with fracture morphology, the smoother fracture surface morphology is related to the maximum tensile and shear joint strength, respectively. The joint strength is increasing with curing temperature and compressive stress, and the joint strength of treatment with 150°C curing temperature and 0.12 kgf/mm2 compressive stresses are larger than its original tensile fracture strength of cured ovalbumin at same curing temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Assessing Damage to Archaeological Artefacts in Compacted Soil Using Microcomputed Tomography Scanning
Authors: McBride R. A. , Mercer G. D. 
Published: October 2011

ABSTRACTThis laboratory study investigated the susceptibility of subsurface archaeological ecofacts/artefacts to incidental damage from utility construction activities, as it pertains to the cultural heritage aspects of environmental impact assessment and municipal planning. The research objective was to use X‐ray microcomputed tomography (micro‐CT) imaging to non‐destructively determine the nature and extent of any damage inflicted on a range of ecofact and artefact types (authentic and replica) embedded in repacked, plastic clay soil by pure soil strain at variable levels of static load compactive effort up to 600 kPa. Uniaxial soil compression testing and micro‐CT imaging were combined procedurally to meet this objective. It was concluded that lithic artefacts were largely immune to damage from stresses up to 600 kPa due to their high strength properties, while moderately fragile ecofacts (replica charred maize kernels) exhibited evidence of dimensional distortion, but not of breakage. Very fragile ecofacts (unionid freshwater clam shells) showed dimensional distortion and minor structural damage at lower stresses (50 and 100 kPa), but significant breakage and fragmentation at higher stresses (300 and 600 kPa). Overall, the micro‐CT technique was shown to be useful in monitoring and describing any breakage or morphometric distortion in a wide range of test ecofacts/artefacts compressed in a clay‐rich soil matrix. However, earthen artefacts, such as terra cotta pottery sherds, were found to be problematic using the micro‐CT imaging technique for this application due to similarities in the densities of the ceramic sherds and the surrounding compressed soil matrix. Copyright © 2011 John Wiley & Sons, Ltd.