bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of molecularly imprinted polymers in supercritical carbon dioxide
Authors: Ye Lei , Yoshimatsu Keiichi , Kolodziej Dorota , Da Cruz Francisco José , Dey Estera S. 
Published: August 2006

AbstractMolecularly imprinted polymer nanoparticles were prepared in supercritical carbon dioxide using a noncovalent imprinting approach. In the present work, propranolol was used as a model template, methacrylic acid as a functional monomer, and divinylbenzene as a crosslinker. Under a high dilution condition, the heterogeneous polymerization resulted in discrete crosslinked polymer nanoparticles. Compared with the nonimprinted polymers, the imprinted nanoparticles displayed much higher propranolol uptake in a low polarity organic solvent. The use of a single enantiomer (S)‐propranolol as the template clearly demonstrated that the imprinted binding sites are chiral‐selective, with a cross‐reactivity towards (R)‐propranolol of less than 5%. The overall binding performance of the imprinted nanoparticles was comparable to imprinted polymers prepared in conventional organic solvents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2863–2867, 2006
Preparation of multiwall carbon nanotubes/poly(p‐phenylene benzobisoxazole) nanocomposites and analysis of their physical properties
Authors: Li X. , Huang Y. D. , Liu L. , Cao H. L. 
Published: August 2006

AbstractRaw multiwall carbon nanotubes (MWNTs) were first treated with strongly oxidated acid to form MWNTs–COOH and driven to a high dispersion quality in the dispersing medium via ultrasonic method. Then the MWNTs/poly (p‐phenylene benzobisoxazole)(MWNTs–COOH/PBO) nanocomposites were prepared by an in situ polymerization technique. In this process, the morphological structure of MWNTs and MWNTs–COOH were investigated by XPS, FTIR, and TEM. The experimental results showed that the carboxyl group was introduced into the surface of nanotubes and the length of nanotubes was shortened. The images of SEM and AFM illustrated that the MWNTs–COOH was homogeneously dispersed in PBO matrix, and the DTA analysis indicated that the molecular weight of MWNTs–COOH/PBO was almost equal to that of PBO. Furthermore, the thermogravimetry results proved that the thermal property of MWNTs–COOH/PBO was more stable than that of PBO. Also, the knot strength and the tensile strength of MWNTs–COOH/PBO were 30% higher than that of PBO. In addition, the reaction route of the MWNTs–COOH and PBO oligomer was given according to the ATR–FTIR spectra of PBO polymer and MWNTs–COOH/PBO. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2500–2508, 2006
Phase transitions of κ‐carrageenan gels in various types of salts
Authors: Kara Selim , Arda Ertan , Kavzak Burhan , Pekcan Önder 
Published: August 2006

AbstractSol–gel and gel–sol phase transitions of κ‐carrageenan in various types of salts were studied using photon transmission technique. Here, LiCl, NaCl, KCl, MgCl2, CaCl2, and SrCl2 were chosen as the proper salts for the κ‐carrageenan–water system. Photon transmission intensity, Itr was monitored against temperature to determine the sol–gel and gel–sol temperatures (Tsg and Tgs) and activation energies (ΔEsg and ΔEgs). It was observed that Tgs temperatures were notably higher than Tsg due to the hysteresis on the phase transition loops. It was observed that stronger carrageenan gels are formed in the presence of KCl compared to the others. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3008–3016, 2006
Graft polymerization of vinyl acetate onto granular starch: Comparison on the potassium persulfate and ceric ammonium nitrate initiated system
Authors: Lai S.‐M. , Don Trong‐Ming , Liu Y.‐H. , Chiu Wen‐Yen 
Published: August 2006

AbstractThis work was undertaken to discuss in depth the vital differences in the morphological development during synthesis, and properties of starch‐g‐poly‐(vinyl acetate) copolymers using two different initiators, potassium persulfate (KPS) and ceric ammonium nitrate (CAN). KPS‐initiated system gave relatively low values of grafting ratio and grafting efficiency, indicating a great tendency for the formation of poly(vinyl acetate) homopolymer (PVAc). Yet, higher values were seen for the CAN‐initiated system. Transmission electron microscope observations indicated a relatively broad distribution of latex particles for the KPS‐initiated system. The surface potential of latex particles was about −3.5 mV, which turned out to be insufficient to maintain stability of latex particles. On the other hand, a uniform particle size distribution was found for the CAN‐initiated system, as the surface potential of latex particles was 21.5 mV. Moreover, radicals on starch molecules were generated directly through a redox reaction with positively charged ceric ion. The hydrophobic PVAc chains were thus grafted on starch, resulting in an amphiphilic graft copolymer, which provides a sufficient stabilization degree as a role of surfactant to render a relatively uniform distribution of latex particles. The synthesized starch‐g‐poly(vinyl acetate) copolymers were further converted to starch‐g‐poly(vinyl alcohol) through saponification, which were subjected to evaluations regarding the biodegradation and cell culture capability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3017–3027, 2006
Crystallization kinetics of novel poly(aryl ether ketone) copolymers containing 2,7‐naphthalene moieties
Authors: Liu Si‐Jie , Sun Xiao‐Bo , Hou Xiang , Wang Gui‐Bin , Jiang Zhen‐Hua 
Published: August 2006

AbstractTo increase the glass transition temperature (Tg) of poly(aryl ether ketone), and to decrease the melting temperature (Tm) and temperature of processing, a series of novel poly(aryl ether ketone)s with different contents of 2,7‐naphthalene moieties (PANEK) was synthesized. We focused on the influence of the naphthalene contents to the copolymer's crystallization. The crystallization kinetics of the copolymers was studied isothermally and nonisothermally by differential scanning calorimetry. In the study of isothermal crystallization kinetics, the Avrami equation was used to analyze the primary process of the crystallization. The study results of the crystallization of PANEK at cooling/heating rates ranging from 5 to 60°C/min under nonisothermal conditions are also reported. Both the Avrami equation and the modified Avrami–Ozawa equation were used to describe the nonisothermal crystallization kinetics of PANEK. The results show that the increase in the crystallization temperature and the content of 2,7‐naphthalene moieties will make the crystallization rate decrease, while the nucleation mechanism and the crystal growth of PANEK are not influenced by the increasing of the content of 2,7‐naphthalene moieties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2527–2536, 2006
Technological and processing properties of natural rubber layered silicate‐nanocomposites by melt intercalation process
Authors: Madhusoodanan K. N. , Varghese Siby 
Published: August 2006

AbstractNatural rubber nanocomposites were produced by melt‐mixing of natural rubber with organically modified silicates. For comparison, a pristine‐layered silicate and a nonlayered version [English Indian clay (EIC)] were also included in the study. The layered silicate used was sodium bentonite (BNT) and organoclays used were octadecylamine‐ modified montmorillonite (MMT‐ODA) and methyltallow bis‐2‐hydroxyethyl ammonium‐modified montmorillonite (MMT‐ TMDA). Accelerated sulfur system was used for the vulcanization of the nanocomposites. The dispersion of these silicates was studied by X‐ray diffraction and transmission electron microscopy. The organoclay‐incorporated composites exhibited faster curing and improved mechanical properties. The improvement in the mechanical properties of the composites followed the order MMT‐ODA > MMT‐TMDA > EIC > BNT. The property improvement was attributed to the intercalation/exfoliation of the organically modified silicates because of their high initial interlayer distance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2537–2543, 2006
Kinetic investigation of ZrO2, Y2O3, and Ni on poly(vinyl butyral) thermal degradation using nonlinear heating functions
Authors: Liau Leo Chau‐Kuang , Chien Yu‐Ching 
Published: August 2006

AbstractThe effects of zirconia (ZrO2), yttria (Y2O3), and nickel (Ni) on poly(vinyl butyral) (PVB) thermal degradation were evaluated using kinetic analysis of TGA data and nonlinear heating rates. An exact solution derived from the Arrhenius equation in an integration form was used for the kinetic analysis. The kinetic parameters of the thermal degradation reaction were determined utilizing the solution and the isoconversional principle. Results show that the reaction pathway of the PVB thermal degradation was altered by the presence of these inorganic materials except ZrO2. The strong catalytic effects of Y2O3, and Ni on the PVB degradation were found and discussed according to the analytical results. The reaction rate was accelerated faster in lower temperatures in the presence of Y2O3, and Ni. The degradation period of the PVB/Ni sample appeared the shortest for these cases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2552–2559, 2006
Toughening and reinforcement of rigid PVC with silicone rubber/nano‐CACO3 shell‐core structured fillers
Authors: Yang Ling , Hu Yuan , Guo Hong , Song Lei , Chen Zuyao , Fan Weicheng 
Published: August 2006

AbstractTo improve the mechanical properties and structure of poly(vinyl chloride) (PVC)/nano‐CaCO3 nano composite, a core (nano‐CaCO3)/shell (SR) structured filler (40–60 nm) was successfully prepared by refluxing methyl vinyl silicone rubber (SR) and nano‐CaCO3 particles (coupling agent KH550, KH560, or NDZ‐101 as interfacial modifier) in toluene with vigorous stirring, according to an encapsulation model. It is effective in rigid PVC composite's toughness and reinforcement. The interfacial modifier's structure and interaction of nanocomposites of PVC/SR/nano‐CaCO3 were studied. The results indicate that KH560 has the optimal interfacial modificatory effect. The environmental scanning electron microscope (ESEM) study testified that PVC/SR/nano‐CaCO3 nanocomposites had a typical rubber–plastics‐toughening mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2560–2567, 2006
Grafting of acrylic acid onto flax fibers using Mn(IV)‐citric acid redox system
Authors: Zahran M. K. , Rehan M. F. 
Published: August 2006

AbstractWhen the flax fibers (machine tow) were treated with KMnO4solution, MnO2was deposited over‐all the fiber surface. The amount of MnO2deposited relied on the KMnO4concentration. Subjecting the flax‐containing MnO2to a solution consisting of monomer (acrylic acid, AA) and citric acid, CA (or any acid used in this work) resulted in formation of poly(AA)‐flax graft copolymer. Dependence of the polymer criteria, namely, the total percentage conversion (%TC) and the carboxyl content of the grafted flax fibers on various grafting parameters, viz., concentrations of the redox pair as well as AA, material‐to‐liquor ratio (M/R), duration and temperature of polymerization, kind of the acid and kind of the flax fibers pretreatment was studied systematically. The results indicated that the polymerizability of AA molecules, expressed as %TC (i.e., counting both grafting and homopolymerization) and thence the carboxyl content (i.e., evaluating the extent of AA grafting along the flax backbone) was optimized with the following conditions: [AA], 100% (based on weight of flax fibers, owf); [CA], 0.4 meq/1 g flax; [MnO2], 0.4 meq/1 g flax; polymerization temperature, 40°C; polymerization time, 30 min; and theM/R, 1 : 50. A tentative mechanism for grafting of flax fibers with AA using MnO2‐acid redox system was elucidated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3028–3036, 2006
Investigation of crystallization of PVCH‐PE‐PVCH triblock copolymer in supercritical carbon dioxide
Authors: Yu Pei‐Qian , Xie Xu‐Ming , Wang Tao , Bates Frank S. 
Published: August 2006

AbstractCrystallization of glassy‐crystalline‐glassy poly(vinylcyclohexane)‐b‐polyethylene‐b‐poly(vinylcyclo hexane) (PVCH‐PE‐PVCH) triblock copolymer treated in supercritical Carbon Dioxide (scCO2) was investigated by using differential scanning calorimetry (DSC) and atomic force microscope (AFM). It was found that the melting temperatures (Tm) and the crystallinity (Xc) of the PVCH‐PE‐PVCH samples treated in scCO2 at different annealing temperatures (T) were all much higher than those of the untreated PVCH‐PE‐PVCH, indicating that the scCO2 could effectively induce the samples to further crystallize. With increasing the T, the Tm of the samples linearly increased, even up to 108°C, close to the Tm (∼ 110°C) of the PE homopolymer hydrogenated from polybutadiene which is equal to the PE block in the triblock copolymer. The results could be ascribed to the released PE chain ends linked to the PVCH block due to the lowered Tg of the PVCH block swollen by scCO2. It suggested that the origin of the confined crystallization in PVCH‐PE‐PVCH was the fixed PE chain ends by the glassy PVCH. AFM images of the samples treated in scCO2 showed that the PVCH lamella phase tended to connect each other and led to the aggregated structures. The result indicated that the PVCH block could be availably swollen by scCO2. It supported the DSC experiment results of the samples treated in scCO2. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2584–2589, 2006
Covalently tethered comb‐like polymer brushes on hydrogen‐terminated Si (100) surface via consecutive aqueous atom transfer radical polymerization of methacrylates
Authors: Zhai Guangqun , Cao Y. , Gao J. 
Published: August 2006

AbstractThe hydrogen‐terminated Si (100) (SiH surface) was functionalized by coupling with 4‐vinylbenzyl chloride (VBC) to form a SiVBC surface, which serves as macroinitiators for the surface‐initiated aqueous atom transfer radical polymerization (ATRP) of 2‐hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)methacrylate (PEGMA) to prepare SiVBCgPHEMA and SiVBCgPPEGMA substrates, respectively. The ellipsometric results revealed that the surface‐initiated ATRP of both PHEMA and PPEGMA brushes proceeded in a controlled fashion. By adjusting the monomer concentration, an eccentric polymer thickness dependence on the initial monomer concentration [M]0 was observed for both HEMA and PEGMA, i.e., in the dilute regime, the thickness of the polymer film increases with the increase in [M]0; however, beyond critical [M]0, the thickness deceases gradually with the further increase. Such an eccentricity was tentatively correlated to the counteractive combination of the increase in [M]0 and decrease in the apparent polymerization rate constant. Both SiVBCgPHEMA and SiVBCgPPEGMA substrates were esterified for the subsequent surface‐initiated ATRP, resulting in corresponding comb‐like brushes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2590–2599, 2006
Stress–strain behavior in uniaxial compression of polymer gel beads
Authors: Egholm Runi D. , Christensen Søren F. , Szabo Peter 
Published: August 2006

AbstractA method for carrying out mechanical testing on spherical microparticles (Versabeads™) has been evaluated using an incompressible viscoelastic finite element model. The mechanical test is based on the compression of a single bead from which stress–strain data are obtained. Simulations based on the finite element model are used to investigate whether or not an apparent elastic modulus found as the slope of the initial close to linear stress–strain curve can be related to the real elastic modulus. The numerical results indicate that the apparent modulus is in fact related to the elastic shear modulus and that the relation Eapp ≈ 4G can be used to obtain the shear modulus from the mechanical test. These results, however, only apply for purely elastic beads. The finite element solution has also been compared to the Hertz's expression relating axial displacement and compression force. Good agreement with the Hertz's expression is obtained at axial displacements below 10% and fit of the Hertz's expression to simulated force–displacement curves leads to a Hertz's modulus that is equal to 4G. This is expected for incompressible materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3037–3047, 2006
Preparation of a kaolinite–poly(acrylic acid acrylamide) water superabsorbent by photopolymerization
Authors: Wan Tao , Wang Xiaoqing , Yuan Yi , He Wenqiong 
Published: August 2006

AbstractA novel kaolinite–poly(acrylic acid acrylamide) water superabsorbent with a water absorbency and salt solution absorbency of 433 and 108 g/g, respectively, was successfully synthesized by the photopolymerization of acrylic acid with acrylamide in the presence of kaolinite powder under 30 min of ultraviolet irradiation at room temperature. The results showed a synergetic effect of the mixed photoinitiators (Michler's ketone and benzophenone) on the water absorbency, and the incorporation of less than 10 wt % kaolinite into the water superabsorbent slightly improved the water absorbency and salt solution absorbency and obviously upgraded the water retention, as demonstrated by retention testing as well as thermogravimetric analysis and differential scanning calorimetry. Fourier transform infrared spectroscopy verified the structure of the kaolinite composite superabsorbent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2875–2881, 2006
Effects of the electrospray ionization parameters on the formation and morphology of colloidal microspheres of polyacrylonitrile
Authors: Hao Xiufeng , Lu Xiaofeng , Li Zhenyu , Zhao Yiyang , Shang Tiecun , Yang Qingbiao , Wang Ce , Li Lijuan 
Published: August 2006

AbstractPolyacrylonitrile colloidal microspheres have been successfully prepared with different concentrations of electrospraying polyacrylonitrile solutions. The morphology of the colloidal spheres has two kinds of structures and is strongly affected by electrospray‐ionization parameters, such as the polymer concentration, applied voltage, and distance between the electrodes. The solvent can also affect the morphology of polyacrylonitrile. The optimum conditions for preparing colloidal spheres have been found, and differential scanning calorimetry results indicate that polyacrylonitrile colloid spheres are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2889–2893, 2006
Effects of the shear flow on a homogeneous polymeric reaction
Authors: Xie Fan , Zhou Chixing , Yu Wei 
Published: August 2006

AbstractThe reaction kinetics of the postamidation of polyamide 6 in the melt was studied by a new rheological method, and the reaction rate constant was calculated to be about 0.087 kg/mol min at 250°C. To study the effects of the shear flow on a homogeneous polymeric reaction, a more practical technique was used to select the data that responded only to the reaction without the effect of different shear flows. The experimental results showed that the reaction rate constant decreased with an increase in the shear rate. Moreover, the decreases in the rates were different under different shear modes: the reaction rate constant decreased slightly under oscillatory shear but strongly under steady shear. Possible reasons for these phenomena were examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3056–3061, 2006
Silicon‐containing heterocyclic polymers and thin films made therefrom
Authors: Hamciuc Corneliu , Hamciuc Elena , Pakula Tadeusz , Okrasa Lidia 
Published: August 2006

AbstractThin films, in the range of tens of micrometers thickness, have been prepared by casting onto glass plates the chloroform or N‐methylpyrrolidone solutions of polyimides or poly(imide‐amide)s containing silicon and phenylquinoxaline units in the main chain. The polymers have been synthesized by solution polycondensation reaction of aromatic diamines having preformed phenylquinoxaline rings with bis(3,4‐dicarboxyphenyl)dimethylsilane dianhydride or with a diacid chloride resulting from the reaction of this dianhydride with p‐aminobenzoic acid. The polymers were easily soluble in polar aprotic solvents and showed high thermal stability. The free‐standing films exhibited good mechanical properties with tensile strengths in the range of 48–86 MPa, tensile modulus in the range of 1.25–2.22 GPa and elongation at break in the range of 3–37%. Electrical insulating properties of some polymer films were evaluated on the basis of dielectric constant and dielectric loss and their variation with frequency and temperature. The values of the dielectric constant at 10 kHz were in the range of 2.94–3.08 for polyimides and 3.89–4.49 for poly(imide‐amide)s. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3062–3068, 2006
Effect of different preparation routes on the structure and properties of rigid polyurethane‐layered silicate nanocomposites
Authors: Woo Tim , Halley Peter , Martin Darren , Kim Dae Su 
Published: August 2006

AbstractTo identify the effect of reactive preparation on the structure and properties of rigid polyurethane (PU)‐layered silicate nanocomposite, a range of nanocomposites were prepared by combining the various precursors in different sequences. The morphology of the samples was characterized by XRD and TEM. Tensile properties and dynamic mechanical thermal properties were measured. The reactions between the layered silicates and PU precursors were monitored via FTIR to gain an understanding of the participation of nanofiller in the polymerization reaction, and the impact of this on system stoichiometry. The XRD and TEM results provided evidence that morphology can differ significantly if different synthesis methods are used. However, the mechanical properties are dominated by the stoichiometry imbalance induced by the addition of the layered silicates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2894–2903, 2006
Morphology of gas‐assisted and conventional injection molded polycarbonate/polyethylene blend
Authors: Zheng Guoqiang , Yang Wei , Yin Bo , Yang Mingbo , Liu Chuntai , Shen Changyu 
Published: August 2006

AbstractThe skin‐core structure of the gas‐assisted and conventional injection molded polycarbonate (PC)/polyethylene (PE) blend was investigated. The results indicated that both the size and the shape of the dispersed PC phase depended not only on the nature of PC/PE blend and molding parameters, but also on its location in the parts. Although the gas‐assisted injection molding (GAIM) parts and conventional injection molding (CIM) part have the similar skin‐core structure, the morphology evolution of PC phase in the GAIM moldings and the CIM moldings showed completely different characteristics. In the section perpendicular to the melt flow direction, the morphology of the GAIM moldings included five layers, skin intermediate layer, subskin, core layer, core intermediate layer as well as gas channel intermediate layer, according to the degree of deformation. PC phase changed severely in the core layer of GAIM moldings, as well as in the subskin of CIM moldings. In GAIM parts, PC phase in the core layer of the nongate end changed far more intensely and aligned much orderly than that in the gate end. The morphology of PC phase in the GAIM part molded with higher gas pressure changed more severe than that in the GAIM part molded with lower gas pressure. In a word, PC phase showed more obvious fibrillation in the GAIM moldings than that in the CIM moldings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3069–3077, 2006