bluuebunny/crossref_metadata_2025 huggingface dataset:
Smart anionic polyelectrolytes based on natural polymer for complexation of cationic surfactant
Authors: Szczubiałka Krzysztof , Rosół Kamila , Nowakowska Maria
Published: August 2006

The thermosensitive polyelectrolytes were obtained by grafting 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) onto hydroxypropylcellulose (HPC), a biodegradable polysaccharide. The interactions of the polymers with dodecyltrimethylammonium chloride (DTAC), a model cationic surfactant, were studied. It was found by the measurements of the surface tension and the analysis of fluorescence emission of pyrene used as a fluorescent probe, that the HPC–AMPS graft polymers strongly interact with DTAC with the formation of polymer–surfactant complexes. The critical aggregation concentrations of these polymer–surfactant systems were found to be of the order of 10−5 mol/dm3. The polymers were found to be potentially useful in the purification of water from cationic surfactants. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2401–2407, 2006
Application of magnetic resonance techniques in investigation of hydrocarbons interaction with composite polymers
Authors: Maddinelli G. , Montanari L. , Ferrando A. , Maestrini C.
Published: August 2006

Composite polymers such as high impact poly stirene (HIPS) or acrylonitrile–butadiene–styrene (ABS) are widely used in manufacturing industry. In special applications, such as refrigerator liners, a good resistance to fluids aggression is required. In this study we have applied NMR and ESR techniques to investigate the effect of diffusion of fluids (light hydrocarbons) used as blowing agents for polyurethanes (thermal insulators) inside selected HIPS materials. The application of NMR relaxation analysis on materials exposed to deuterated hydrocarbons (C6D12) allowed selective observation of rubber phase modification. Both longitudinal (T1) and transversal (T2) relaxation provided information on polymer chain dynamics effects, determined by solvent interactions. In fact, a consistent increase in relaxation times of polybutadiene rubber phase after solvent exposition was observed. Similar results were obtained by using hexachlorobutadiene as solvent. Another confirmation was also obtained by spin‐probe ESR technique. This technique could give useful insight into the molecular mobility of the two phases of HIPS. This experimental investigation provided a clear demonstration of consistent solvent penetration inside the rubbery phase of such composite polymers. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2810–2817, 2006
Determination of thermodynamic and transport properties of solvents and non solvents in poly(L‐lactide‐co‐glycolide)
Authors: Eser Hulya , Tihminlioglu Funda
Published: August 2006

Thermodynamic properties, partition coefficient, and diffusion coefficients of the various solvents (acetone, dichloromethane, trichloromethane, ethyl acetate, ethyl alcohol, tetrahydrofuran, and water) in poly(lactide‐co‐glycolide) (PLGA) at infinite dilution of the solvent have been determined by inverse gas chromatography (IGC). In IGC method, which is based on the characteristic equilibrium partitioning of a solute between a mobile phase and a stationary phase, a small pulse of solvent is introduced into the column and by the aid of retention volume of the solvent, several polymer solvent interaction properties, namely retention volume (Vg), infinitely dilute weight fraction activity coefficient (Ω), Flory–Huggins interaction parameter (χ), and solubility parameters of the polymer (δ) can be determined. The thermodynamic results indicated that trichloromethane and dichloromethane were the most suitable solvents among all the solvents studied for PLGA. The partition (K) and diffusion coefficients (Dp) of various solvents at infinite dilution of the solvent were calculated by using the model developed by Pawlisch et al. (Macromolecules 1987, 20, 1564). The optimum K and Dp values that best fit the data were found and the model predicted experimental data very well. So IGC method is a powerful tool for the determination of thermodynamic and diffusion properties of solvent in polymer at infinite dilution of the solvent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2426–2432, 2006
Porous polyphenylene sulfide membrane with high durability against solvents by the thermally induced phase‐separation method
Authors: Ding Huaiyu , Zeng Yiming , Meng Xiangfu , Tian Ye , Shi Yanqiao , Jiao Qingze , Zhang Shimin
Published: August 2006

Porous polyphenylene sulfide membranes were prepared as new solvent‐resistant membranes by the thermally induced phase‐separation (TIPS) method. Porous structures were either formed by solid–liquid phase separation (polymer crystallization) or liquid–liquid phase separation. The effects of solvents, cooling rates, and polymer concentrations on the porous structures were investigated. Various characteristics of pore structure can be obtained with suitable diluents and cooling rates using the TIPS method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2959–2966, 2006
A new macroinitiator for the synthesis of triblock copolymers PA12‐b‐PDMS‐b‐PA12
Authors: Rached R. , Hoppe S. , Jonquieres A. , Lochon P. , Pla F.
Published: August 2006

A new PDMS macroinitiator is proposed for the anionic ring‐opening polymerization of lactams. This α,ω‐dicarbamoyloxy caprolactam PDMS macroinitiator was readily obtained in quantitative yield, by an original synthesis scheme in two steps, which involved the scarcely reported reaction of isocyanates with silanol groups. It was then shown that this bifunctional macroinitiator enabled to synthesize triblock copolymers PA12‐b‐PDMS‐b‐PA12 by polymerization of lauryl lactam (LL) at high temperature (200°C) in inert atmosphere under conditions compatible with reactive extrusion processes. Another related high molar weight α,ω‐diacyllactam PDMS macroinitiator was also successfully used in the polymerization of LL under the same conditions, therefore overcoming the limitations formerly reported for this type of macroinitiators during the polymerization ε‐caprolactam (ε‐CL) at a much lower temperature (80°C). Triblock copolymers with a wide range of PA12 /molar weights (Mn: ∼ 10,800–250,000 Da) were eventually obtained by using both types of macroinitiators. DMTA and DSC analyses showed that their thermal properties were strongly dependent upon their respective contents in soft and hard blocks. Such triblock copolymers already appear very promising for the highly effective in situ compatibilization of PA12/PDMS blends as shown by recent complementary results obtained in our laboratory. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2818–2831, 2006
Effects of ammonium dibasic phosphate pretreatment time on the structure and properties of PAN‐based activated carbon hollow fibers
Authors: Sun Junfen , He Chunju , Zhu Sijun , Wang Qingrui
Published: August 2006

Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate aqueous solution, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of pretreatment time of PAN hollow fibers in ammonium dibasic phosphate aqueous solution on the microstructure, specific surface, pore‐size distribution, and adsorption properties of PAN‐based activated carbon hollow fibers (PAN‐ACHF) were studied in this work. After the activation process, the Brunaner–Emmett–Teller (BET) surface area of the PAN‐ACHF and surface area of mesopores in the PAN‐ACHF increases and reaches 513 m2 g−1 and 66 m2 g−1 respectively, when the dipping time of PAN hollow fibers in ammonium dibasic phosphate aqueous solution is 30 min. The adsorptions to creatinine and VB12 of PAN‐ACHF are much high, reach 95% and 86% respectively, when dipping time is 30 min. The dominant pore sizes of mesopores in PAN‐ACHF range from 2 nm to 5 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2448–2453, 2006
Adsorption characteristics of benzene on electrospun‐derived porous carbon nanofibers
Authors: Shim Wang Geun , Kim Chan , Lee Jae Wook , Yun Je Jung , Jeong Young Il , Moon Hee , Yang Kap Seung
Published: August 2006

The adsorption properties of polyacrylonitrile (PAN) carbon nanofibers fabricated by using an electrospinning route were assessed for their applicability as a novel alternative adsorbent. Commercial fiber, A–10, was chosen for comparison. Nitrogen adsorption/desorption isotherms and gravimetric techniques were used to examine the porous structure, adsorption equilibrium, kinetics, and the energetic heterogeneity of the prepared adsorbent. The nitrogen adsorption and desorption isotherms showed that PAN carbon nanofibers are highly microporous with small amounts of mesoporous regions. The equilibrium data of benzene was obtained at three different temperatures (343.15, 383.15, and 423.15) K with pressures up to 4 kPa. The data correlated successfully with the Toth isotherm equation. In addition, by using this isotherm model, the adsorption affinity and isosteric enthalpy of adsorption were determined. The results of the isosteric enthalpy of adsorption and adsorption energy distribution tests/equations revealed that although PAN carbon nanofibers have a heterogeneous surface, they seem to be more homogeneous than commercial carbon fibers. Moreover, the mass transfer and thermal desorption results showed that shallow pores contained within PAN carbon nanofibers may be effective adsorbents for removing toxic compounds. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2454–2462, 2006
Compatibility of PTET‐60/CA blends and separation performance of their membranes for benzene/cyclohexane mixture by pervaporation
Authors: Bai Yunxiang , Qian Jinwen , Zhao Qiang , Xu Yong , Ye Shengrong
Published: August 2006

Aromatic copolyester of poly(trimethylene‐co‐ethylene terephthalate) (PTET) with different composition was synthesized and the PTET sample with 60% weight fraction of polytrimethylene (PTET‐60) was amorphous. The compatibility of PTET‐60/cellose acetate (CA) blends and the pervaporation of their membranes for separation of benzene/cyclohexane mixtures were investigated. It was found that PTET‐60 is compatible with CA when the weight fraction of PTET‐60 in PTET‐60/CA blends (WPTET‐60) is lower than 0.35 and more than 0.5. Both the degree of swelling (DS) and the permeation flux (J) of these blend membranes increased with increasing WPTET‐60 from 0 to 0.35, and a maximum value of the separation factor (α) displayed at WPTET‐60 = 0.25. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2832–2838, 2006
PSA performances and viscoelastic properties of SIS‐based PSA blends with H‐DCPD tackifiers
Authors: Lim Dong‐Hyuk , Do Hyun‐Sung , Kim Hyun‐Joong
Published: August 2006

Hotmelt pressure sensitive adhesives (PSAs) usually contain styrenic block copolymers like styrene–isoprene–styrene (SIS), SBS, SEBS, tackifier, oil, and additives. These block copolymers individually reveal no tack. Therefore, a tackifier is a low molecular weight material with high glass transition temperature (Tg), and imparts the tacky property to PSA. The SIS block copolymer with different diblocks was blended with hydrogenated dicyclopentadiene (H‐DCPD tackifier), which has three kinds of Tg. PSA performance was evaluated by probe tack, peel strength, and shear adhesion failure temperature. PSA is a viscoelastic material, so that its performance is significantly related to the viscoelastic properties of PSAs. We tested the viscoelastic properties by dynamic mechanical analysis and the thermal properties by differential scanning calorimeter to investigate the relation between viscoelastic properties and PSA performance. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2839–2846, 2006
Preparation of (S)‐ibuprofen‐imprinted polymer and its molecular recognition study
Authors: Hung Chin‐Yin , Huang Yun‐Tzu , Huang Han‐Hung , Hwang Ching‐Chiang
Published: August 2006

Two molecularly imprinted polymers (MIPs) were prepared using (S)‐ibuprofen as the template molecule as well as methacrylic acid (MAA) or 4‐vinylpyridine and ethylene glycol dimethacrylate (EGDMA) as the functional monomer and crosslinker, respectively. Free radical polymerization was carried out at 4°C under ultraviolet (UV) radiation. The MIPs thus obtained were ground into 25–44 μm, which were slurry packed into analytical columns. The template molecules were removed by acetic acid/methanol solution (1:9, v/v). high‐performance liquid chromatography (HPLC), with UV detection, was used to evaluate the binding performance of the MIP for the template. The selectivity of (S)‐ibuprofen and naproxen on the host–guest system were assessed using acetonitrile‐based mobile phases. The limits of detection of ibuprofen and naproxen were found to be 0.1844 mmol/L and 0.3264 mmol/L, while the limits of quantitation were 0.6262 mmol/L and 1.0909 mmol/L, respectively. The stationary phase was applied successfully to the commercial tablet analysis. Ibuprofen and naproxen were extracted from tablets with acetonitrile; analysis results showed a good relative standard deviation (RSD) of 0.81–1.24% and accuracy from −4.01 to +2.98% for ibuprofen as well as an RSD of 0.59–0.86% and accuracy from −4.01 to −2.01% for naproxen. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2972–2979, 2006
Non‐isothermal crystallization kinetics and melting behaviors of poly(butylene succinate) and its copolyester modified with trimellitic imide units
Authors: Liu Xiaoqing , Li Chuncheng , Xiao Yaonan , Zhang Dong , Zeng Wan
Published: August 2006

With the help of differential scanning calorimeter (DSC), the basic thermal behaviors, nonisothermal crystallization kinetics, and subsequent melting behaviors of poly(butylene succinate) (PBS) and its copolyester (PBSTMA) modified with trimellitic imide units were investigated in this paper. The DSC thermograms of PBS and PBSTMA showed that the crystallization behaviors of PBS were affected seriously because of the addition of a small quantity of trimellitic imide units. The nonisothermal crystallization processes of them were represented by the Avrami equation modified by Jeziorny and the method developed by Ozawa. After that, the conception of “crystallization rate coefficient (CRC)” introduced by Khanna was employed. The values of CRC for PBS and PBSTMA are 174.6 and 88.2 h–1, respectively. At the end of this paper, the melting behaviors of PBS and PBSTMA after being cooled from 130 to 30°C at different cooling rate were studied in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2493–2499, 2006
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

Molecularly 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

Raw 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

Sol–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

This 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

To 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

Natural 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

The 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

To 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

When 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

Crystallization 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

The 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

A 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

A 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

Polyacrylonitrile 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

The 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

Thin 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

To 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

The 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
Epoxy resin modified with soybean oil containing cyclic carbonate groups
Authors: Parzuchowski Pawel G. , Jurczyk‐Kowalska Magdalena , Ryszkowska Joanna , Rokicki Gabriel
Published: August 2006

Carbonated soybean oil (CSO) containing five‐membered cyclic carbonate groups has been obtained in the reaction of epoxidized soybean oil with carbon dioxide in the presence of KI activated by 18‐crown‐6 under 6 MPa CO2 pressure at 130°C. The CSO was used for modification of bisphenol‐A based epoxy resin. The composition epoxide‐cyclic carbonate was cured using polyamine hardeners by one‐step and two‐step procedures. All cured compositions were characterized for their thermal and mechanical properties and compared with the parent epoxy network. The optimal properties were obtained for compositions containing CSO and cured by one‐step method when phase separation takes place. The mechanical properties were discussed in terms of morphology observed by SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2904‐2914, 2006
Investigation of correlations between mucoadhesion and surface energy properties of mucoadhesives
Authors: Xiang Jun , Li Xiaoling
Published: August 2006

To explore the correlations between mucoadhesion and the surface properties of mucoadhesive polymers, a series of polymer, poly[acrylic acid‐co‐poly(ethylene glycol) monomethylether monomethacrylate‐co‐dimethylaminoethyl methacrylate], poly(AA‐PEGMM‐DMEMA), was designed and synthesized as a model mucoadhesive in this study. Poly(AA‐PEGMM‐DMEMA) was prepared by free radical polymerization. The composition of the polymer was varied by changing the content of DMEMA from 0 to 2.9 mol %, while keeping the mole ratio of AA to PEGMM at constant 9:1. The contact angles of water, glycerol (GL), or diiodomethane (DIM) on the surface of polymers with different hydration levels were measured, respectively. Surface energy components of the Lifshitz–van der Waals and the Lewis acid–base interactions for the polymer were calculated, based on the measured contact angles of water, GL, and DIM. The free energy of mucoadhesion (ΔG) of the polymer on the buccal surface was estimated by interfacial free energy of a ternary system, consisting of mucin, polymer, and normal saline. The mucoadhesion of the polymer was measured after prehydration for 0, 5, and 180 min. It was found that Lewis acid–base interactions and Lifshitz–van der Waals interactions played different roles in the process of mucoadhesion. Increasing Lewis acid–base interaction between the polymer and the buccal mucosa led to a thermodynamically favorable adhesion process. Hydration could greatly affect mucoadhesion by changing the thermodynamic properties of the surface. Restricted hydration promoted the formation of mucoadhesive joints. The force of mucoadhesion was correlated mathematically with the effects of various interactions involved in the process of mucoadhesion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2608–2615, 2006
Geological and geophysical investigations in the Roman cemetery at Kenchreai (Korinthia), Greece
Authors: Sarris A. , Dunn R. K. , Rife J. L. , Papadopoulos N. , Kokkinou E. , Mundigler C.
Published: August 2006

The Kenchreai Cemetery Project (KCP) comprises an interdisciplinary archaeological research team that is exploring a major cemetery of Roman date in southern Greece. The cemetery is located on the Koutsongila Ridge just north of the ancient harbour of Kenchreai, the prosperous eastern port of Corinth. Surface remains that have been visible for centuries or exposed by looting include chamber tombs, cist graves and architecture. In 2004 KCP conducted geological and geophysical investigations to reconstruct the natural and settled landscape where ancient residents buried their dead. Geological study of the ridge and its vicinity has determined that the tombs are situated within a geologic unit particularly well suited for rock‐cut construction, and that tombs were intentionally cut into the bedrock so that the vaulted roofs corresponded with a particularly resistant calcareous horizon (caliche), which provided a stable ceiling for the subterranean chambers. Moreover, several metres of coastline have eroded into the Saronic Gulf since antiquity. A systematic geophysical survey using electromagnetic, magnetic, ground‐penetrating radar and gravity techniques was also carried out to map uncovered remains and to correlate visible with subsurface features. Several anomalies were identified that might represent previously unknown large structures and burial sites in the central and southern areas of the ridge. In addition, experimental tests using GPR and micro‐gravitometry demonstrated the efficacy of these methods for surveying rock‐cut tombs. The combined results of geological and geophysical investigation provide valuable information concerning local resource exploitation, structural distribution, and environmental change. These investigations model an innovative approach to the study of mortuary landscapes. Copyright © 2006 John Wiley & Sons, Ltd.
A cluster‐based approach for efficient content‐based image retrieval using a similarity‐preserving space transformation method
Authors: Shah Biren , Raghavan Vijay , Dhatric Praveen , Zhao Xiaoquan
Published: August 2006

The techniques of clustering and space transformation have been successfully used in the past to solve a number of pattern recognition problems. In this article, the authors propose a new approach to content‐based image retrieval (CBIR) that uses (a) a newly proposed similarity‐preserving space transformation method to transform the original low‐level image space into a high‐level vector space that enables efficient query processing, and (b) a clustering scheme that further improves the efficiency of our retrieval system. This combination is unique and the resulting system provides synergistic advantages of using both clustering and space transformation. The proposed space transformation method is shown to preserve the order of the distances in the transformed feature space. This strategy makes this approach to retrieval generic as it can be applied to object types, other than images, and feature spaces more general than metric spaces. The CBIR approach uses the inexpensive “estimated” distance in the transformed space, as opposed to the computationally inefficient “real” distance in the original space, to retrieve the desired results for a given query image. The authors also provide a theoretical analysis of the complexity of their CBIR approach when used for color‐based retrieval, which shows that it is computationally more efficient than other comparable approaches. An extensive set of experiments to test the efficiency and effectiveness of the proposed approach has been performed. The results show that the approach offers superior response time (improvement of 1–2 orders of magnitude compared to retrieval approaches that either use pruning techniques like indexing, clustering, etc., or space transformation, but not both) with sufficiently high retrieval accuracy.
Determination of myoseverin embryotoxic potential by using FETAX
Authors: Vismara Claudio , Bacchetta Renato , Muzio Andrea Di , Mantecca Paride , Tarca Silvia , Vailati Giovanni , Colombo Roberto
Published: August 2006

BACKGROUND: Since MYS is a microtubular poison with a reversible activity, Xenopus blastulae were exposed to MYS to verify the eventual drug‐related developmental suspension and the reversibility of this effect. METHODS: Lethal and teratogenic effects of myoseverin (MYS) were evaluated using the FETAX. Embryos were exposed to different MYS concentrations from stage 8 to stage 47. RESULTS: Probit analysis gave 12.14 µM LC50 and 7.67 µM TC50 from which 1.58 T.I. is derived. Several malformations were observed such as facial abnormalities, abnormal tail flexure, heart ventricle chamber enlargement and external appendix. MYS led to an arrest of living embryo development. Before MYS removing, exposed blastulae showed the lack of mitotic spindles along with different nuclei alterations. Living embryos, moved in control solution, mainly died around the hatching showing severe malformations likely ascribable to the altered planes of newly occurring mitosis. CONCLUSION: In spite of the low T.I, MYS has to be considered a highly teratogenic compound. Birth Defects Res (Part B) 77, 2006. © 2006 Wiley‐Liss, Inc.
Risk of congenital anomalies in pregnant users of non‐steroidal anti‐inflammatory drugs: a nested case‐control study
Authors: Ofori Benjamin , Oraichi Driss , Blais Lucie , Rey Evelyne , Bérard Anick
Published: August 2006

BACKGROUND: Many women take non‐steroidal anti‐inflammatory drugs (NSAIDs) during pregnancy but the risks for the infant remain controversial. We carried out a study to quantify the association between those women prescribed NSAIDs in early pregnancy and congenital anomalies. METHODS: A population‐based pregnancy registry was built by linking data from three administrative databases in Quebec between 1997–2003. The inclusion criteria were mothers of live singleton infants, between 15–45 years of age, covered by the RAMQ drug plan ≥12 months before and during pregnancy, and prescribed an NSAID or other medications during pregnancy. We selected as cases infants with any congenital anomaly (ICD‐9; 740‐759) diagnosed in the first year of life. Up to 10 controls, defined as infants with no congenital anomalies detected were selected for each case. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated. RESULTS: Within the registry, 36,387 pregnant women met the inclusion criteria. We identified 93 births with congenital anomalies in 1056 women (8.8%) who filled prescriptions for NSAIDs in the first trimester of pregnancy, compared to 2478 in 35,331 (7%) women who did not. The adjusted OR for any congenital anomalies for women who filled a prescription for NSAIDs in the first trimester was 2.21 (95% CI=1.72–2.85). The adjusted OR for the anomalies related to cardiac septal closure was 3.34 (95% CI=1.87–5.98). There were no significant associations with anomalies of other major organ systems. CONCLUSIONS: Our study suggests that women prescribed NSAIDs during early pregnancy may be at a greater risk of having children with congenital anomalies, specifically cardiac septal defects. Birth Defects Research (Part B), 2006. © 2006 Wiley‐Liss, Inc.