bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the substitution degrees on the optical properties of cellulose acetates
Authors: Necula Adina Maria , Olaru Niculae , Olaru Liliana , Homocianu Mihaela , Ioan Silvia 
Published: October 2009

AbstractCellulose acetates with different substitution degrees possess a set of properties that makes them highly suitable for optical applications. This article discusses some of these properties, namely refractivity, dielectric properties, and transmittance. The contribution of the ratio between the molar refraction, which is proportional to the induced dipole moment, and the molar volume for the different atoms present in the studied polymers to the optical properties was investigated. The study illustrates the importance of such structural and compositional characteristics in tailoring some specific optical applications. Furthermore, optical transmission has been investigated in the 200–1000 nm range. To obtain the optical parameters, the approach proposed by Tauc for amorphous semiconductors has been used because of the similarity of the absorption edges. The values of pseudogap energy ranged between 3.44 and 4.70 eV, whereas those of Urbach energy were modified in the 18–37 meV range. All parameters determined have been related to the influence of the substitution degrees and of the synthesis condition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic behavior of photo‐polymerization of UV‐curable resins with carboxylic acid and amino groups
Authors: Kuo Kuo‐Huai , Chiu Wen‐Yen , Don Trong‐Ming 
Published: October 2009

AbstractPhoto‐polymerization behaviors of bisphenol‐A epoxy diacrylate (EPA) and six kinds of EPA‐derived resins containing different amounts of carboxylic acid, urethane, amide, and imide groups were studied by a photo differential scanning calorimetry. The dark polymerization was performed and pseudo‐steady state assumption of growing radicals was made to obtain the kinetic constants for propagation, bimolecular termination, monomolecular termination, and the concentration of growing radicals of different resins as a function of extent of reaction. Compared with EPA, it was found that the rate of polymerization and kinetic constants of the six resins were relatively small because the mobility of reacting species in resins was restricted by carboxylic acid, urethane, amide, and imide groups. Finally, three different photo‐initiators were used to initiate the polymerization, and their kinetic behaviors were compared. The effect of tertiary amine group of photo‐initiator on the rate of polymerization of resins having carboxylic acid group and the initiator efficiency were discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and properties of electrospun PAN/Fe3O4 magnetic nanofibers
Authors: Wang Biao , Sun Ying , Wang Huaping 
Published: October 2009

AbstractPolyacrylonitrile (PAN)/Fe3O4 composite nanofibers were prepared via the electrospinning of the PAN spinning solutions with magnetite Fe3O4 nanoparticles. The experimental results showed that the morphology and diameter of the nanofibers strongly depended upon concentrations of PAN and salt additives in the spinning solutions. A suitable PAN concentration and LiCl additives could effectively prevent the occurrence of beads in the electrospinning process and affected the diameters of the electrospun nanofibers. The breaking strength and breaking strain decreased when the magnetite Fe3O4 nanoparticles were incorporated. The prepared PAN/Fe3O4 nanofibers were superparamagnetic at room temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Investigation of cytotoxic effects of new maleic anhydride binary and ternary copolymers on L929 mouse fibroblasts
Authors: Can Hatice Kaplan , Gürpinar Özer Aylin , Onur Mehmet Ali , Rzaev Zakir M.O. , Güner Ali 
Published: October 2009

AbstractThe purpose of this study was to investigate the cytotoxic effects of poly(MA‐alt‐AA) and poly [MA‐co‐AA‐co‐(VA)] in cell culture model. Complex‐radical copolymerization (CTC) of maleic anhydride (MA), and acrylic acid (AA) and ternary polymerization of (MA), vinyl acetate (VA) and AA, considered as acceptor−donor−acceptor systems, were carried out. For the cytotoxicity study, cells were incubated at initial density of 50,000 cells/mL in 24‐well plates. After 24‐h incubation, the culture medium was removed and fresh medium containing five different dilutions of polymers were added separately. Cell viability and proliferation were assessed on 1st and 5th days. Apoptosis was assessed using propidium iodide/acridine orange (PI/AO) staining at the 1st and 5th days of incubation. Kruskal‐Wallis test was applied to compare the effects of different dilutions on cell viability at each evaluation period. The results showed that there were differences between co‐ and terpolymer in view of cell proliferation and apoptotic response. The results suggest that functional groups in co‐ and terpolymer group may cause apoptotic cell death without effecting cell proliferation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Multifunctional formaldehyde resins as curing agent for epoxy resins
Authors: Mustata Fanica , Bicu Ioan 
Published: October 2009

AbstractFormaldehyde resins (FR) at 1/1/2 molar ratios of monomers (Cl‐phenol/amino monomers/p‐formaldehyde) were synthesized under acid catalysis. The obtained resins were characterized using elemental analysis, FTIR and RMN spectroscopic methods, being used as crosslinking agents for epoxy resin formulations. The curing of epoxy resins with FR were investigated. The glass transition temperature (Tg) and decomposition behavior of crosslinked resins were studied by differential scanning calorimetry (DSC) and thermogravimetric (TGA) techniques. All DSC scans show two exothermic peaks, which implied the occurrence of cure reactions between epoxy ring and amine or carboxylic protons, in function of chemical structures of FR. The crosslinked products showed good thermal properties, high glass transitions, and low water absorption. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Electrospun poly(D,L‐lactide) and polyaniline scaffold characterization
Authors: McKeon K. D. , Lewis A. , Freeman J. W. 
Published: October 2009

AbstractNeuromuscular disease or peripheral nerve damage can interrupt muscle contraction, but tissue engineered constructs can be created to combat this problem. Electrospinning provides a way to create a degradable nonwoven mesh that can be used to culture cells and tissues. Conductive polymers can be blended with other polymers to provide an electrical current to increase cell attachment, proliferation, and migration. We electrospun several polyaniline and poly(D,L‐lactide) (PANi/PDLA) mixtures at different weight percents including the following PANi‐PDLA solutions (w/v): 24% (83% PDLA/17% PANi), 24% (80% PDLA/20% PANi), 22% (75%PDLA/25% PANi), 29% (83% PDLA/17% PANi), and 29% (80% PDLA/20% PANi). Only the 75/25 electrospun scaffold was able to conduct a current of 5 mA. The calculated electrical conductivity for this scaffold was 0.0437 S/cm. Primary rat muscle cells were cultured on all three of the scaffolds and on tissue culture polystyrene as a positive control. Although the scaffolds degraded during this process, cells were still able to attach and proliferate on each of the different scaffolds. The cellular proliferation measurements showed no significant difference between the four groups measured. The conductivity and cellular behavior demonstrate the feasibility of fabricating a biocompatible, biodegradable, and electrically conductive PDLA/PANi scaffold. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication and characterization of a solid polymeric electrolyte of PAN‐TiO2‐LiClO4
Authors: Rahman M. Y. A. , Ahmad A. , Ismail L. H. C. , Salleh M. M. 
Published: October 2009

AbstractThe ionic conductivity of PAN‐TiO2‐LiClO4 as a function of TiO2 concentration and temperature has been reported. The electrolyte samples were prepared by solution casting technique. Their conductivity was measured using the impedance spectroscopy technique. The highest room temperature conductivity of 1.8 × 10−4 S cm−1 was obtained at 7.5 wt % of TiO2 filler. It was observed that the relationship between temperature and conductivity were linear, fitting well in Arrhenius and not in Vogel‐Tamman‐Fulcher equation. The pre‐exponential factor, σ0 and Ea are 1.8 × 10−4 S cm−1 and 0.15 eV, respectively. The conductivity data have been supported by differential scanning calorimeter (DSC) analysis. DSC analysis showed that there was a significant change in glass transition temperature (Tg) with the filler concentration. The SEM micrograph revealed that the TiO2 particles are dispersed in the electrolyte, thus enhancing its conductivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Low‐phosphorus maleic acid and sodium ρ‐styrenesulfonate copolymer as calcium carbonate scale inhibitor
Authors: Wang Chen , Zhu Deyi , Wang Xikui 
Published: October 2009

AbstractIn this article, a multifunctional and environment‐friendly agent for industry circulation cooling water, maleic acid and sodium ρ‐styrenesulfonate copolymer containing low‐phosphorus was synthesized in aqueous solution with hypophosphorous acid/hydrogen peroxide as redox initiators. The effects of monomer feed ratio, temperature, dose of hypophosphorous acid, and drop speed of hydrogen peroxide on calcium carbonate inhibition were investigated, and the experimental conditions were optimized using orthogonal method. The composition and structure of the copolymer were analyzed by enery‐dispersive X‐ray analysis, fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results of the static scale inhibition tests showed that the copolymer was effective in inhibiting the formation of calcium carbonate scale. The calcium carbonate precipitates formed in the static tests were examined by scanning electronic microscopy and X‐ray diffraction spectra. The results indicate that in the presence of the copolymer the calcium carbonate precipitate is the mixture of calcite and vaterite that could be stabilized kinetically in the presence of the copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
pH‐sensitive hydrogels based on bovine serum albumin for anticancer drug delivery
Authors: El‐Sherif Hazem , El‐Masry Mansour , Taleb Manal F. Abou 
Published: October 2009

AbstractProtein conjugates consisting of hydroxyethyl methacrylate and acrylic acid monomers in the presence of bovine serum albumin (BSA) were prepared by gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The study parameter was the BSA content in the as‐prepared conjugates. Polymers were characterized with FTIR, scanning electron microscopy (SEM), and swelling studies. The polymerization reaction caused the rearrangement of the BSA carbonyl hydrogen bonding and finally led to the modification of the BSA secondary structure as proved by FTIR. SEM proved that the prepared conjugates matrices are porous, with a three‐dimensional interconnected microstructure. The swelling kinetics of the hydrogels and the release dynamics of an anticancer model drug (flutamide) have been studied. High equilibrium swelling values, up to 1550%, could be observed and were correlated with the increase in pH, temperature, and BSA content. The mechanism of swelling changed from Fickian to non‐Fickian by reducing the acidity of the medium. This study proved that there is a direct relationship between the protein content in the conjugates and both the loaded and the released drug. These pH responsive conjugates may be exploited for the delivery of flutamide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of UV‐curable/alkali‐soluble dispersants used for black photoresist with a high loading of carbon black
Authors: Kuo Kuo‐Huai , Chiu Wen‐Yen , Don Trong‐Ming 
Published: October 2009

AbstractThis research synthesized a functional dispersant, not only providing a good dispersion of carbon black (CB) but also possessing ultraviolet (UV)‐curable and alkali‐soluble properties, by a two‐step process. Firstly, bisphenol‐A epoxy diacrylate was reacted with benzophenone tetracarboxylic dianhydride at different molar ratios to obtain UV‐curable/alkali‐soluble resins. In the second step, these resins would possess dispersion ability of CB by reaction with an isocyanate‐containing methacrylate. The prepared dispersants were evaluated by their dispersion ability and the light absorption property of CB. The results showed that one of the dispersants was able to disperse CB in the solvent up to 10 wt % with a mean particle size about 100 nm. This particular dispersant had a moderate amount of amino‐containing groups (such as urethane, amide, and imide) serving as anchoring sites on CB, and a sufficiently long chain (Mn ∼ 2600) to provide a steric repulsion among CB particles. The advantage of this CB/dispersant system is that no other curable resins are needed. By using a suitable photoinitiator, the present CB/dispersant system could reach a polymerization rate of 1.05 × 10−3 (s–1), and a black pattern of 10 μm in width on a glass substrate was obtained through an UV‐lithography process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nonrigid microporous PVC sheets: Preparation and properties
Authors: Trommer Kristin , Morgenstern Bernd 
Published: October 2009

AbstractThe non‐rigid microporous PVC films are prepared by mono‐axially stretching nonporous sheets containing fillers which show an average particle size of 2 to 10 μm. The nonporous PVC film is generated from paste‐like PVC. The influence of recipe components on the mechanical properties, morphological behavior and permeability to water vapor and water was investigated as well as the influence of the stretching ratio. Filled PVC pastes exhibit higher values for viscosity than those of pure polymer mixtures. For processing the compounded paste by means of a doctor blade a low viscosity is required meaning the amount of filler is limited by the resulting paste viscosity. Due to dewetting, the filler initiates the holes of the microporous system during the stretching process. Empirically, a minimum of about 15 vol % filler particles are necessary in order to achieve an interconnected air hole system. Varying the components PVC, plasticiser and filler, PVC membranes could be prepared with high water vapour permeability and high waterproofness simultaneously. To utilize the membranes commercially a continuous preparation process was developed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Utilization of plant ash for the fabrication of novel superabsorbent composites with potassium‐release characteristics
Authors: Wang Wenbo , Wang Aiqin 
Published: October 2009

AbstractDesign and synthesis of the agricultural and ecological superabsorbent materials with cost‐efficient and fertilizer‐release characteristics has recently attracted considerable interests. In this work, the novel poly(sodium‐potassium acrylate‐co‐acrylamide)/plant ash (PNa‐KA‐co‐AM/PA) superabsorbent composites with potassium‐release characteristics were prepared using partially neutralized acrylic acid (Na‐KA), acrylamide (AM), and plant ash (PA) as raw materials, ammonium persulfate (APS) as the initiator, and N,N′‐methylenebisacrylamide (MBA) as the crosslinker. The structure, morphologies, and thermal stability of the composites were characterized by Fourier transform infrared spectrophotometer, scanning electron microscopy, and TGA techniques, respectively. The effects of MBA concentration and PA content on water absorbency were studied, and the swelling properties of the composites in saline solutions and various pHs solution as well as their potassium‐release capabilities were also evaluated. Results indicate that the composites exhibit better thermal stability, salt‐resistant performance, pH‐stability, and potassium‐release properties, and can act as a fertilizer and an effective water‐saving material for agricultural and ecological application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Photografting of methacrylic acid onto hydroxyapatite particles surfaces
Authors: Gao Jun , Huang Bin , Lei Jingxin , Zheng Zhiming 
Published: October 2009

AbstractThe unsaturated functional groups (CC) were introduced onto hydroxypatite (HAP) particles surfaces by esterification reaction between hydroxyl groups on the HAP surface and methacrylic acid (MAA). Then, graft polymerization of MAA onto the esterified HAP particles surfaces was carried out by ultraviolet light (UV) initiation. The structure of the surface‐esterified and grafted HAP was studied by ESCA, FTIR, Scanning Electron microscopy, laser particle sizes analyze, esterification, and graft degrees tests. The results show that poly(methyl acrylic acid) (PMAA) is successfully inserted onto HAP particles surfaces by covalent bond linkage. The esterification degree between MAA and HAP particles increases with reaction temperature and time, and tends to level off at about 6 h under 90°C. The graft degree of MAA onto HAP particles with 1.14% esterification degree and its average particle sizes increase with UV initiation polymerization time, and to reach a maximum at 25 min under 40°C, then decrease as irradiation time further increases. The surfaces of the grafted HAP particles become rough and loose. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(ethylene terephthalate‐co‐isophthalate) copolyesters obtained from ethylene terephthalate and isophthalate oligomers
Authors: Ubach Joan , de Ilarduya Antxon Martínez , Quintana Robert , Alla Abdelilah , Rudé Elisabet , Muñoz‐Guerra Sebastián 
Published: October 2009

AbstractA series of poly(ethylene terephthalate‐co‐isophthalate) copolyesters containing upto 50%‐mole of isophthalic units were prepared by polycondensation from ethylene terephthalate and ethylene isophthalate fractions of linear oligomers containing from 5 to 6 repeating units in average. The polyesters were obtained in good yields and with high‐molecular‐weights. The microstructure of the copolyesters was studied as a function of reaction time by 13C‐NMR showing that a random distribution of the comonomers was achieved since the earlier stages of polycondensation. The melting temperature and enthalpy of the copolyesters decreased with the content of isophthalic units so that copolyesters containing more than 25% of these units were amorphous. Isothermal crystallization studies made on crystalline copolyesters revealed that the crystallization rate of copolyesters decreased with the content in isophthalic units. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Microstructural parameters in electron‐irradiated C108 silk fibers by wide‐angle X‐ray scattering studies
Authors: Sangappa  , Asha S. , Sanjeev Ganesh , Subramanya G. , Parameswara P. , Somashekar R. 
Published: October 2009

AbstractThe present study looks into the microstructural changes in C108 (Bombyx mori) silk fibers, induced by electron irradiation. The irradiation process was performed in air at room temperature by the use of 8 MeV electron accelerators at different doses: 0, 25, 50, 75, and 100 kGy, respectively. The changes in microstructural parameters in these natural polymer fibers have been studied using wide‐angle X‐ray scattering method. The crystal imperfection parameters such as crystallite size 〈N〉, lattice strain (g in %), and enthalpy (α*) have been determined by line profile analysis using Fourier method of Warren. Exponential, lognormal, and Reinhold functions for the column length distributions have been used for the determination of these parameters. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of dilution with PMMA and network formation on fluorescence from benzimidazolylphenylenes linked to PMMA network
Authors: Wongjuntaramanee Kunapong , Tsuchiya Masahiro , Ishimaru Kaori , Kojima Takakazu 
Published: October 2009

AbstractN,N′‐5‐(2‐benzimidazolyl)‐1,3‐phenylenebis(methacrylamide) (BIPBMA) was synthesized and copolymerized with methyl methacrylate (MMA) by changing feed BIPBMA/MMA molar ratio. The swelling experiments suggest that these cross‐linked copolymers (c‐copolymers) have a polymer network structure. To compare with c‐copolymers, synthesized 3‐(2‐benzimidazolyl) phenylmethacrylamide (BIPMA) was copolymerized with MMA by changing feed BIPMA/MMA molar ratio. These linear copolymers (l‐copolymers) were dissolved in N,N‐dimethylacetamide (DMA). The fluorescence spectra of c‐copolymers were well fitted by trial‐and‐error contraction with sums of five or less of Lorentzian equations. The fluorescence spectra of l‐copolymers were so distributed that only the initial peak was fitted to a single Lorentzian equation. The fluorescence spectra of BIPBMA/DMA solutions with various concentrations were also fitted to sums of five or less of Lorentzian equations. The fitted coefficients were used to quantify dilution effect. The fluorescence intensity of c‐copolymers is higher than that of l‐copolymers in a same chromophore concentration. A relation between the intensity and the chromophore concentration shows a concentration quenching owing to chromophore aggregating for c‐copolymer, l‐copolymer, and the solution. A critical concentration point before which the intensity increases appeared in the plots of intensity against concentration for the c‐copolymer and the solution. The critical point of the c‐copolymer is higher than that of the solution and that of the l‐copolymer (if observed). This suggests that the network formation and the dilution break up the chromophore aggregates. The fluorescence spectra of c‐copolymers (1/200) adjusted by varying AIBN concentrations suggest that the fluorescence is independent of the extent of cross‐linking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studies on water absorption of bamboo‐epoxy composites: Effect of silane treatment of mercerized bamboo
Authors: Kushwaha Pradeep K. , Kumar Rakesh 
Published: October 2009

AbstractThe effect of silane treatment on the water absorption properties of bamboo matting reinforced epoxy composites were investigated. Experiments using γ‐aminopropyltriethoxy silane, 3‐trimethoxysilylpropylmethacrylate, vinyltris(2‐methoxyethoxy)silane, bis[3‐(triethoxysilyl)propyl]tetrasulfide, 3‐aminopropyltrimethoxysilane, and n‐octyltrimethoxysilane were carried out to improve the water resistant property of the bamboo fiber composites. Water absorption in the composites was studied by long term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 41 to 26%. Further reduction is observed with silane treatment. Water absorption varies between 21 and 24%, minimum being for aminopropyltriethoxysilane treated composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010