bluuebunny/crossref_metadata_2025_split huggingface dataset:
Submicron nanoporous polyacrylamide beads with tunable size for verapamil imprinting
Authors: Nematollahzadeh Ali , Abdekhodaie Mohammad J. , Shojaei Akbar 
Published: December 2011

AbstractSubmicron sized polyacrylamide particles were prepared via modified precipitation polymerization method. Experimental design based on Taguchi approach was employed to study the influence of the polymerization composition including monomer (acrylamide), crosslinker (methylenebisacrylamide), initiator (azobisisobutyronitrile), and modifier (polyvinylpyrrolidone, K‐30), on the size and morphology of the particles. Varying the polymerization composition, submicron‐particles with sizes ranging between 100 and 600 nm were achieved. In all the cases, polydispersity index (PDI) of the particle size was found to be almost 1 indicating uniformity of the particle size. The concentration of crosslinker was found to be the most influential parameter on the particles size and the modifier concentration as an extra tunable parameter was believed to affect the nucleation mechanism and the viscosity of the medium to help controlling the particle size. To validate the optimization, particles with a preset diameter, i.e., 500 nm, were synthesized based on the composition predicted by the mathematical correlation. The polymer with the preset particle size was also imprinted with verapamil and characterized by FTIR, DSC, SEM, physisorption, elemental analysis, swelling, and batch rebinding experiments. The verapamil imprinted polymers bearing nano‐cavities exhibited high affinity with imprinting factor 2.17 towards the target molecule. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Linear and star branched perylene‐containing polyimides: Synthesis, characterization, and photovoltaic properties of novel donor–acceptor dyes used in solar cell
Authors: Niu Haijun , Luo Jun , Wu Wenjun , Mu Jingshan , Wang Cheng , Bai Xuduo , Wang Wen 
Published: December 2011

AbstractA series of novel linear and star branched triphenylamine‐containing aromatic polyimides (AI, AII, AIII) were designed and synthesized by the condensation of 4‐aminotriphenylamine(I), 4,4′‐diamino triphenylamine(II), 4,4′,4″‐triamino triphenyl‐amine(III) with perylene‐3,4,9,10‐tetra‐carboxylic dianhydride to investigate the influence of topological structure on the energy levels and photophysical performance. The polyimides were characterized by elemental analysis, FTIR, and 1H‐NMR. The onset temperatures for 5% weight loss determined by thermoanalysis were between 415 and 428°C. The results of UV–vis spectra, quantum chemical calculation, and cyclic voltammetry revealed that introduction of triphenylamine group changed the energy levels of entire dye system. The aggregation way of polymers was also studied by the methods of UV–vis spectra, X‐ray diffraction (XRD), atom force microscopy, and the molecular simulation. The dye‐sensitized solar cells prepared by using the series of dyes showed big photoelectric response. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Morphology formation in polypropylene impact copolymers under static melt conditions: A simulation study
Authors: Remerie Klaas , Groenewold Jan 
Published: December 2011

AbstractIn this article, the equilibrium morphology of a typical polypropylene (PP) impact copolymer (ICP) system is investigated by numerical self‐consistent field simulations. The ICP was fractionated using temperature rising elution fractionation (TREF) to obtain the data necessary to define the simulation parameters. The results demonstrated the formation of a stratified droplet structure, in which ethylene content decreases from the center of the droplet toward the PP interface. This structure is shown to be in accordance with observations from transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. The components are confined to a narrow layer whose position is primarily determined by its ethylene content. Leakage into a neighboring layer occurs to a degree that is determined by the component molecular weight and the difference in ethylene content between the layers. Simulations for a range of droplet sizes enable calculation of the interfacial tension. A typical drawback of TREF involves the inability to fractionate the amorphous part, leading to a large difference in ethylene content between the matrix and its neighboring layers. Although this effect is shown not to have a significant influence on the stratified structure, it is shown to have a significant influence on the derived interfacial tension. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Oxygen barrier and mechanical properties of masterbatch‐based PA6/nanoclay composite films
Authors: Fasihi Mohammad , Abolghasemi Mohammad Reza 
Published: December 2011

AbstractThis study focuses on the possibility of improving performance properties of polyamide‐6 (PA6) nanocomposite films for packaging application using nanoclay masterbatch. Different concentrations of nanoclay in PA6 were prepared through melt‐mixing of particulate nanoclay and nanoclay masterbatches in a twin screw compounder, then film samples were molded using a hot press. Oxygen barrier properties were then measured and interpreted on the basis of different theoretical approaches. Also, a correlation between morphology and properties of the studied nanocomposites was observed, and all prepared nanocomposites exhibited performance improvement with increasing the nanoclay content. The masterbatch‐based nanocomposite films showed more exfoliated regions that leading to the enhancement of the mechanical properties. Gas permeability through nanocomposite films decreased significantly just by loading a small amount of nanoclay. However, surprising behavior in oxygen permeability observed at higher levels of nanoclay in masterbatch‐based nanocomposite was attributed to the decreased crystallinity of PA6 matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effectiveness of silane monomer on chitosan films and PCL‐based tri‐layer films
Authors: Sharmin Nusrat , Khan Ruhul A. , Salmieri Stéphane , Dussault Dominic , Lacroix Monique 
Published: December 2011

AbstractChitosan films were prepared by casting from its 1% (w/w) solution. Tensile strength (TS), tensile modulus (TM), and elongation at break (Eb%) of chitosan films were found to be 30 MPa, 450 MPa, and 8%, respectively. Silane monomer (3‐aminopropyl tri‐methoxy silane) (1–7%, w/w) was added into the chitosan solution (1%, w/w), and films were casted. The highest TS (38 MPa) and TM (620 MPa) values were found at 5% (w/w) silane content films. Polycaprolactone (PCL) films were prepared by compression molding; the values of TS, TM, and Eb of PCL films were found to be 12 MPa, 226 MPa, and 70%, respectively. Using chitosan and silane containing chitosan films, PCL‐based tri‐layer films were prepared by compression molding. Chitosan (also silane‐incorporated chitosan) content in the tri‐layer films varied from 10 to 50% by weight. The values of TS and TM of the silane containing composites were found to be 21 and 410 MPa, respectively, which is significantly higher (40% TS and 34% TM) than control composites. Molecular interactions due to silane addition were supported by FT‐IR analysis. The surface of the films and the interface of the tri‐layer films were investigated by scanning electron microscope (SEM). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Substrate effect on the crystallization of isotactic polypropylene
Authors: Lin Yuan , Fan Yurun 
Published: December 2011

AbstractThe evolution of storage modulus measured by a rotational rheometer shows that the isothermal crystallization of isotactic polypropylene (iPP) melts in contact with aluminum plates (PP‐Al) are considerably faster than that with stainless‐steel plates (PP‐SS). The difference is bigger at higher temperatures, and this behavior is opposite to that expected by our numerical simulation considering uniform bulk phase transition and substrate's ability to remove the latent heat. Polarized optical observations and surface energy evaluations via contact angle measurement indicate that surface energy of the substrates, including the effects of submicrometer morphology and roughness, should be the key factor to affect the crystallization of iPP. Transcrystallization zones, in which the nucleation density is controlled by the surface energy of substrates, were observed to grow toward the bulk with the thickness of about 0.2 mm for iPP to affect the global crystallization behavior. The critical value of surface energy of substrate to promote the interfacial crystallization of a polymer melt is derived, in terms of which the aluminum and stainless steel as well as optical glass, promote the surface nucleation with respect to the bulk nucleation of iPP. As a consequence, the conventional differential scanning calorimetry measurement mainly gives the heat fluxes of interfacial crystallization rather than the bulk crystallization due to the large surface‐to‐volume ratio of the specimen and the aluminum pan used which is a high surface energy substrate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Adsorption behavior of As(III) onto chitosan resin with As(III) as template ions
Authors: Liu Bingjie , Lv Xin , Wang Dongfeng , Xu Ying , Zhang Li , Li Yujin 
Published: December 2011

AbstractA novel, biobased chitosan resin was successfully synthesized, characterized, and applied for the selective removal of As(III) from aqueous solutions. Batch adsorption experiments were performed to evaluate its adsorption conditions, selectivity, and reusability. The results showed that the maximum adsorption capacity was 2.16 mg/g, observed at pH 6 and 40°C. Equilibrium adsorption was achieved within 8 h. The kinetic data, obtained at optimal pH 6, could be fitted with a pseudosecond order equation. Adsorption process could be well described by Langmuir adsorption isotherm model and the maximum adsorption capacity calculated from Langmuir equation was 4.45 mg/g. The selectivity coefficient of As(III) ions and other metal cation onto As‐ICR indicated an overall preference for As(III) ions, which was much higher than nonimprinted chitosan resins. Finally, the adsorption mechanisms were studied by Fourier transform infrared spectra, X‐ray diffraction, and differential scanning calorimetry analysis. The result reveals that the adsorption of As‐ICR for As(III) is a chelation process. These results earlier confirmed that As‐ICR is a very promising sorbent for selective adsorption of As(III) ions from aqueous solutions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Ion imprinted beads embedded cryogels for in vitro removal of iron from β‐thalassemic human plasma
Authors: Ergün Bahar , Baydemir Gözde , Andaç Müge , Yavuz Handan , Denizli Adil 
Published: December 2011

AbstractMolecular recognition based Fe3+ imprinted poly(GMA‐MAC) (MIP) beads embedded PHEMA composite cryogel was prepared for selective removal of Fe3+ ions from β‐thalassemia patient plasma. The precomplexation was achieved by the coordination of Fe3+ ions with N‐methacryloyl‐(L)‐cysteine methyl ester (MAC‐Fe3+). MIP beads were prepared by dispersion polymerization in the presence of MAC‐Fe3+ complex and glycidyl methacrylate (GMA) monomer. Then the MIP beads were embedded into poly(hydroxyethyl methacrylate) (PHEMA) cryogel. The specific surface area and the swelling degree of the PHEMA‐MIP composite cryogel were found to be 76.8 m2/g and 7.7 g H2O/g cryogel, respectively. The maximum adsorption amount of Fe3+ ions was 2.23 mg/g. The relative selectivity of PHEMA‐MIP composite cryogel towards the Fe3+ ions was 135.0, 61.4, and 57.0 times greater than that of the PHEMA‐NIP cryogel as compared with the Ni2+, Zn2+, and Fe2+ ions, respectively. PHEMA‐MIP composite cryogel was recovered and reused many times without any significant decrease in its adsorption capacity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mild synthesis of benzylated bamboo in LiCl/DMSO solution
Authors: Li Ming‐Fei , Sun Shao‐Ni , Xu Feng , Sun Run‐Cang 
Published: December 2011

AbstractBenzylated bamboo was mildly synthesized in nonaqueous medium without mercerization pretreatment. The ball‐milled bamboo was firstly preswelled in lithium chloride/dimethyl sulfoxide (LiCl/DMSO) solution and then reacted with benzyl chloride in the presence of solid NaOH with varying molar ratios of benzyl chloride to OH groups of bamboo (1–4), reaction times (1–8 h), and temperatures (60–90°C). Benzylated bamboo products with yields from 51.1 to 106.9% and with degrees of substitution [DS, apparent value evaluated by Fourier transform infrared (FTIR) spectra] between 0.2 and 1.2 were synthesized. FTIR and 13C cross polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy confirmed the incorporation of benzyl groups into bamboo; SEM observations of the highly benzylated bamboo showed porous surface with small irregular slices ascribed to the disruption of intermolecular and intramolecular hydrogen bonds between cellulose. Because of the degradation of amorphous components, the crystallinity decreased negligibly after modification and the thermal stability increased slightly but was lower than that of cellulose. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterization of new soluble multisite phase transfer catalysts and their catalysis in free radical polymerization of methyl methacrylate aided by ultrasound—A kinetic study
Authors: Murugan Eagambaram , Tamizharasu Gurusamy 
Published: December 2011

AbstractFour different soluble phase transfer catalysts (PTCs) containing single, di, tri, and tetra active sites have been prepared and proved by FT‐IR, 1H NMR, 13C NMR, mass, elemental analysis, and conductivity measurement. The presence of the number of active sites in each catalyst was also been confirmed by determining their rate of polymerization of methyl methacrylate (MMA) using potassium peroxydisulfate (PDS) as a water soluble initiator in biphase medium. The comparative study reveals that the Rp of MMA determined in the presence of PTC combined with ultrasound has shown twofold enhancement in the activity than PTC alone. The observed order of activity was found to be of single‐site < di‐site < tri‐site < tetra‐site. Further, the thorough kinetic study of free radical polymerization of MMA has been investigated using superior tetra site viz., HBTAMPDTC and by varying the experimental parameters such as [MMA], [K2S2O8], [MPTC], and the temperature. Based on the observed kinetic results and activation parameters, a suitable mechanism was proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Surface modification of silica–PAN composite nanofibers induced by CO2‐pulsed laser
Authors: Salehi Esfandarani M. , Johari M. , Amrollahi R. , Karimi M. 
Published: December 2011

AbstractIn this study, the modification induced by CO2‐pulsed laser on the surface morphology of silica–polyacrylonitrile composite nanofibers has been investigated. Applied surface modification method is based on different infrared adsorption of materials. Two types of composite nanofibers containing silica nanoparticles with various diameters are irradiated with CO2‐pulsed laser of 1084 wavenumber (cm−1). Surface morphology of irradiated composite nanofibers was analyzed using field emission scanning electron microscope (FE‐SEM). FE‐SEM scans show characteristic modification on the surface of nanofibers with controlled distribution and dimension. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Formation mechanism of microvoids and microcracks of poly(vinyl chloride) under an artificial aging environment
Authors: Xiang Jun , Wang Jiliang , Chen Xiaofeng , Lei Jingxin 
Published: December 2011

AbstractDegradation behaviors of both the unplasticized and plasticized poly(vinyl chloride) (UPVC and PPVC) under an artificial accelerating aging condition were extensively studied. The dependence of mechanical properties, average molecular weight (MW), and surface morphology of the earlier PVC on aging time was investigated by tensile tests, gel penetrate chromatogram (GPC), and scanning electron microscope (SEM), respectively. Fourier transform infrared and ultraviolet (UV)–visible spectroscopy were used to evaluate the probable formation of both the oxygen‐containing groups and the conjugated sequences during aging. The results reveal that UPVC is much easier to be degraded than PPVC under the same testing conditions. The irradiated surface is detected to change from an even topology into a rough topology initially, and then follows the appearance of many voids even cracks in the SEM morphology. During the aging process, oxygen‐containing groups and conjugation of PVC molecular chains around the cracks are observed, and noticeably increase with aging time. However, visible difference of the corresponding MWs of PVC before and after aging is not detected. Moreover, a novel degradation mechanism nearly related to the formation of microvoids and microcracks based on the cohesion energy of groups along PVC molecular chains is developed and semiquantitatively discussed. It is detected that the formation of microvoids and microcracks is attributed to both the thermodynamic changes of PVC backbone during the aging and the aggregation of oxygen‐containing groups with relatively large volumes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and properties of an amphoteric polycarboxylic acid‐based superplasticizer used in sulfoaluminate cement
Authors: Guo Wenjuan , Sun Na , Qin Jianjian , Zhang Jin , Pei Meishan , Wang Yingfei , Wang Shengnian 
Published: December 2011

AbstractA novel amphoteric polycarboxylic (APC) acid‐based superplasticizer was prepared by solution copolymerization from maleic anhydride, allyl polyethylene glycol, and methacryloxyethyltrimethyl ammonium chloride (DMC). The cationic monomer DMC was introduced for improving the performances of sulfoaluminate cement (SAC) with APC. The condition on preparation of APC was determined by the orthogonal experiment, and the performances of fresh and hardened superplasticized mortars were assessed. APC was characterized by FTIR spectra. Adsorption amount and dispersing effectiveness of APC were also investigated. Results indicated that APC could improve the fluidity and enhance the mechanical performances of SAC mortars. Adsorption amount of APC in SAC is large. Compared with an anionic PC superplasticizer and a commercial superplasticizer Visco Crete 3390, APC has the better performance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical properties and fire retardant behavior of polyurethane foam reinforced with oil palm empty fruit bunch
Authors: Tay G. S. , Ong L. N. , Rozman H. D. 
Published: December 2011

AbstractThe objective of this study was to investigate the effects of isocyanate/hydroxyl ratio and ammonium polyphosphate (APP) content on the properties of polyurethane foam. Polyurethane (PU) foam was prepared from polymeric diphenylmethane diisocyanate and polyethylene glycol with molecular weight of 200, reinforced with oil palm empty fruit bunch (EFB) using one shot process. The effect of EFB content on the properties of PU foam was also studied. It was noticed that EFB enhanced the properties of the PU foam. This was due to EFB acting as hard segment in PU foam system. The NCO/OH ratio played an important role in determining the properties of the PU foam produced. However, since EFB is a highly flammable material, APP was introduced to the PU foam system. From the results, APP improved the fire retardant behavior of the PU foam. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation of the surface area and polarity of porous copolymers of maleic anhydride and divinylbezene
Authors: Maciejewska M. , Szajnecki Ł. , Gawdzik B. 
Published: December 2011

AbstractPorous copolymers of maleic anhydride (MA) and divinylbezene (DVB) in the form of regular microspheres were prepared by suspension polymerization. During copolymerization the mixture of 1,4‐dioxane and n‐dodecane as a pore‐forming diluent was used. It was found that specific surface area of the obtained beads is strongly dependent on the diluent system and polymerization medium and achieves a value from 4 to 535 m2/g. To determine the influence of polymerization medium on the selectivity and polarity of the copolymers, inverse gas chromatography (IGC) was applied. To determine these parameters, three procedures were applied: overall polarity, the selectivity triangle, and the ΔC method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Graphite functionalization for dispersion in a two‐phase lubricant oligomer mixture
Authors: Kanniah Vinod , Wang Binghui , Yang Ying , Grulke Eric A. 
Published: December 2011

AbstractFluids with thermally conductive nanoparticles can provide improved heat transfer. Practical nanofluids will be likely based on lubricating oils for the continuous phase and systems that have extended service temperature ranges. A model system based on poly(α‐olefin) synthetic base oil modified with poly(dimethylsiloxane) to lower the mixture's pour point with graphite as a conductive additive was studied. Phase separation of the oligomer mixture occurred at temperatures less than ‐15°C. Graphite particles were etched using citric acid pretreatment to create hydroxyl and carboxyl groups on their surfaces. A coupling reaction between the hydroxyl groups on graphite and chloro groups on silanes gave rise to poly(α‐olefin)‐philic graphite particles. Similarly, a coupling reaction between the carboxyl groups on graphite surface and amine groups on silanes gave rise to poly(dimethylsiloxane)‐philic graphite particles. SEM, FT‐IR, and TG‐MS measurements were used to verify the presence of coupling agents on the surface and to estimate the thickness of the coatings. Upon separation of the mixture, each functionalized graphite type migrated exclusively to its preferred phase. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Biodegradable nanocomposites of cellulose acetate phthalate and chitosan reinforced with functionalized nanoclay: Mechanical, thermal, and biodegradability studies
Authors: Gaurav Aashish , Ashamol A. , Deepthi M. V. , Sailaja R. R. N. 
Published: December 2011

AbstractBiodegradable nanocomposites of cellulose acetate phthalate and chitosan reinforced with functionalized nanoclay (NC) were prepared. The NC loading was varied from 0 to 10%. The mechanical and thermal properties have been investigated for these composites. The nanocomposites exhibited enhanced mechanical properties due to the addition of NC. The scanning electron micrographs of the blend specimens also support the above observations. Thermogravimetric analyses were carried out to assess the degradation stability of the blends. The blend shows an increase in the rate of biodegradation and water uptake with higher loading of NC. The exfoliation of NC was analyzed by X‐ray diffraction studies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012