bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of UV‐initiated RAFT crosslinking polymerization of dimethacrylates
Authors: Zhuo Ding , Ruan Yingbo , Zhao Xuemei , Ran Rong 
Published: February 2011

AbstractThe UV‐initiated RAFT polymerizations of a series of poly(ethylene glycol) dimethacrylates (PEGDMA) were investigated using differential scanning photocalorimetry (DPC) at room temperature. The rate of the RAFT system was much lower than that of a conventional free radical polymerization. A mild autoacceleration occurred as the addition reaction became diffusion controlled. The influence of the spacer length (CH2CH2O)x between the vinyl moieties of the dimethacrylates on the polymerization kinetics was examined. The polymerization rate of PEGDMA decreased with an increased x value from 4 to 9, but it increased with a further increased x value from 9 to 14. Mechanical properties of the resulting polymers were also examined by dynamic mechanical analysis (DMA). It was concluded that the presence of the RAFT agent during polymerization of multifunctional monomers did not have an effect on the heterogeneity of the polymer network. In comparison with three different PEGDMAs, the PEGDMA with the longest spacer formed the most homogeneous networks with a lower crosslinking density. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of poly(ethylene glycol)‐b‐poly(ε‐caprolactone)‐b‐poly(2‐(2‐aminoethyl amino)ethyl methacrylate) triblock copolymers as efficient gene delivery vectors
Authors: Yuan Zhe‐Fan , Li Feng , Ma Ming , Cheng Si‐Xue , Zhuo Ren‐Xi 
Published: February 2011

AbstractIn this study, ABC‐type triblock copolymers, poly(ethylene glycol)‐b‐poly(ε‐caprolactone)‐b‐poly(2‐(2‐aminoethyl amino) ethyl methacrylate)s (PEG‐PCL‐PAEAEMAs), composed of novel poly(2‐(2‐aminoethyl amino) ethyl methacrylate) (PAEAEMA) that have a primary and a secondary amino group in each monomeric unit, were synthesized successfully. It was found that the length of PAEAEMA segments did not have obvious influence on the DNA‐binding capacity and other biophysical properties (size and zeta potential values of polymer/pDNA complexes) , but longer PAEAEMA chains led to a better buffering capacity. The triblock copolymers could mediate efficient gene expression that was similar to branched 25‐kDa polyethylenimine (25 kDa PEI) in the absence of serum and even superior to 25 kDa PEI in the presence of serum in COS‐7 cells. Low cytotoxicity of these polymers was also found in COS‐7 cells. As a result, PEG‐PCL‐PAEAEMAs are attractive candidates as serum‐tolerable gene carriers in biomedical field. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Core‐shell method of synthesis, characterizations, and ac conductivity studies of polyaniline/n‐TiO2 composites
Authors: Roy Aashis S. , Anilkumar Koppalkar R. , Prasad M. V. N Ambika 
Published: February 2011

AbstractPolyaniline/nano‐titanium dioxide composites (PANI/n‐TiO2) were prepared using α‐dextrose as surfactant and ammonium per sulfate as oxidant. The PANI/n‐TiO2 composite is characterized by Fourier transform infrared spectra and confirmed the presence of benzenoid and qunoide ring structures and also formation of free ions. The transmission electron microscopy study reveals that the size of TiO2 is in the order of 7 nm where as the composite size is of the order of 13 nm; further, it is observed that the TiO2 particles are intercalated to form a core shell of PANI. The X‐ray diffraction (XRD) studies show that the monoclinic structure of the composites. ac Conductivity, permittivity, and tangent loss studies on these samples suggest that these composites may be well suited for gas sensor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Microbial modification of polyethylene terephthalate fabric
Authors: Akkaya Alper , Pazarlioglu Nurdan Kasikara 
Published: February 2011

AbstractA great disadvantage of synthetic fibers is their low hydrophilicity. Polyester fibers are particularly hydrophobic. In the first place, this affects the processability of the fibers. The surfaces are not easily wetted, thus impeding the application of finishing compounds and coloring agents. In addition, a hydrophobic material hinders water from penetrating into the pores of fabric. An additional advantage is a decrease in build‐up of electrostatic charge. Besides an improved processability of hydrophilic textiles, a number of advantages from the consumer's point of view are improved washability, as the water can remove hydrophobic stains more easily, and enhanced wearing comfort due to greater water absorbency. For these reasons, hydrophilicity of polyester fabrics was improved using Trametes versicolor. Incubation conditions were determined as; the polyester fabrics were incubated for 10 days at 28°C and 175 rpm. The modification medium was contained 1 g/L glucose and pH of medium was 4. The modification degree was determined according to the contact angle measurements. Water retention values were compatible with contact angle values. FTIR and SEM images showed that the modification occurred on the PET fabric surface. More hydrophilic PET fabric was made by T. versicolor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of a coupling agent on the properties of hemp‐hurd‐powder‐filled styrene–butadiene rubber
Authors: Wang Jie , Wu Weidong , Wang Wencai , Zhang Jianchun 
Published: February 2011

AbstractStyrene–butadiene rubber (SBR) composites filled with hemp hurd powder (HP) were prepared with bis(3‐triethoxysilylpropyl) tetrasulfide (Si69) as a coupling agent. The effects of the filler content and coupling agent on the curing characteristics and dynamic mechanical properties of the composites were studied. The results indicate that with increasing filler loading, the torque values increased and the curing time decreased. The mechanical properties improved with increasing filled HP content up to 60 phr. Usually, long fibers led to a sharp decrease in the toughness of the composites, whereas short fibers, such as HP, had a positive effect on the elongation at break within the loading range studied. The extent of the filler–matrix interaction and the scanning electron micrographs of the fractured surfaces confirmed that the addition of Si69 improved the interfacial interaction between HP and the SBR matrix, which led to an increase in the maximum torque and the mechanical properties. Moreover, the coupling agent was helpful in dispersing the filler in the rubber matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and properties of a high‐molecular‐weight poly(amic acid) and polyimide based on 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane
Authors: Zheng Yanhong , Zhai Yu , Li Guangzhu , Guo Baohua , Zeng Xinmiao , Wang Liancai , Yu Hongyan , Guo Jianmei 
Published: February 2011

AbstractThe feasibility of using the conventional two‐step procedure involving the thermal imidization of a high‐molecular‐weight poly(amic acid) (PAA) for the preparation of self‐supporting polyimide (PI) films was studied. Synthesized PAA and PI were analyzed with respect to their molecular weights, chemical structures, and mechanical and thermal properties. The results showed that a high‐molecular‐weight PAA was successfully synthesized from 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane with 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride. The high intrinsic viscosity of PAA was 1.5 dL/g. Self‐supporting PI films were successfully prepared by the thermal imidization of PAA and reached maximum tensile strength, tensile modulus, and elongation at break values of 103 MPa, 2.2 GPa, and 10.7%, respectively. The PI films were stable to 426–483°C (the 5% weight loss temperature) and had a glass transition at 271–283°C. All these results indicate that the conventional two‐step procedure involving thermal imidization is a promising method for preparing self‐supporting PI films with reasonable levels of mechanical and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A gradient anodic oxidation method for treating polyacrylonitrile‐based high‐modulus carbon fibers
Authors: Hou Yongping , Sun Tongqing , Wang Haojing 
Published: February 2011

AbstractWe describe a gradient anodic oxidation method. Polyacrylonitrile‐based high‐modulus carbon fibers were treated by the conventional and gradient anodic oxidation methods. The results show that the carbon fibers treated by the gradient method possessed a more stable tensile strength, larger NaOH uptake, shallower striations, flatter fracture surface of composites, and better interlaminar shear strength compared to those treated by the conventional method. This indicated that the gradient method was more effective in restricting the etching reaction and improving the adhesion between the carbon fibers and matrix, and we give a suggested explanation of the mechanisms. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Diphenylselenonium 2,3,4,5‐tetraphenylcyclopentadienylide‐initiated polymerization of styrene and acrylonitrile: Synthesis, characterization, reactivity ratios, and thermal properties
Authors: Singh Anamika , Kamal Meet , Singh D. K. 
Published: February 2011

AbstractSolution copolymerization of styrene (Sty) and acrylonitrile (AN) was carried out in dioxane at 60 ± 1°C for 90 min using diphenylselenonium 2,3,4,5‐tetraphenylcyclopentadienylide (selenonium ylide) as radical initiator. The kinetic expression is as follows: Rp ∼ [Ylide]0.5 [Sty]1.0 [AN]1.0. The overall activation energy is 28.72 kJ mol−1. The composition of copolymer calculated from 1H‐NMR and elemental analysis was used to evaluate reactivity ratio as r1 (Sty) = 0.351 and r2 (AN) = 0.0185, using kelen‐Tudos method. It confirmed the alternating nature of the copolymer. The copolymer was characterized using Fourier transform infrared (FTIR) spectroscopy, 1H‐NMR, 13C‐NMR, differential scanning calorimetry, and thermal gravimetric analysis. Electron spin resonance spectroscopy confirmed the presence of the phenyl radical responsible for initiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A thorough study on the relationships between dispersion quality and viscoelastic properties in carbon black filled SBR compounds
Authors: Leblanc Jean L. , Putman Matthew , Pianhanuruk Ekkawit 
Published: February 2011

AbstractA series of carbon black filled SBR 1500 compounds (without curatives) were prepared in carefully controlled lab‐mixing conditions so that filler content ranged from 0 to 50 phr, with the usual compounding ingredients. Carbon Black agglomeration and dispersion quality were assessed through an advanced microscopic technique with automated data treatment. Linear and nonlinear viscoelastic properties were evaluated using a closed cavity torsional rheometer, equipped for Fourier Transform rheometry experiments. In the linear viscoelastic regime, dynamic moduli mastercurves were derived from experiments in the 60−160°C temperature range. In the nonlinear viscoelastic regime, complex modulus and torque harmonics variation with strain amplitude were investigated at 100°C and frequency 0.5 and 1.0 Hz. Relationships between dispersion quality, carbon black loading and mixing parameters were investigated so that dispersion appears better when the filler loading is above a critical level that to some extent (but not exactly) corresponds to the theoretical percolation threshold (around 13%). Linear and nonlinear viscoelastic measurements demonstrate and quantify the role played by plasticizing compounding ingredients, that is, processing oil, stearic acid and other chemicals, with nearly no significant effect of mixing energy. At least 10−15 phr carbon black are necessary to recover the modulus loss associated with this plasticizing effect. Nonlinear results and particularly the torque harmonics reveal a number of details as to how the compounding ingredients do affect the viscoelastic behavior, with expectedly the carbon black playing the major role. By fitting results with mathematically simple models, all of the observed effects can be summarized in a rather limited number of parameters so that the effects of compounding ingredients can be studied in details. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of POSS particles on the mechanical, thermal, and morphological properties of PLA and Plasticised PLA
Authors: Turan Dilek , Sirin Humeyra , Ozkoc Guralp 
Published: February 2011

AbstractThe mechanical, thermal, and morphological properties of melt compounded aminopropylisobutyl‐polyhedral oligomeric silsesquioxane (POSS)/poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG)‐plasticized PLA composites were investigated. It was found that the addition of POSS to the PLA reduced the melt viscosity of the composites acting as a lubricating agent. Dynamic mechanical analysis and tensile tests showed that the modulus and elongation at break values improved at low (1% and 3%) POSS loading levels. Scanning electron microscopy observation indicated that POSS particles were well dispersed in both PLA and plasticized PLA. The interfacial interaction of POSS with the polymer matrix was found to be better in the presence of plasticizer. The presence of POSS also affected the thermal properties of the PLA and plasticized PLA. It was revealed from DSC that POSS particles acted as a nucleating agent for PLA. Moreover, the percent crystallinity was found to be higher in the presence of POSS for both PLA and plasticized PLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Miscibility and crystallization behaviors of biodegradable poly(butylene succinate‐co‐butylene terephthalate)/phenoxy blends
Authors: Li Zhisheng , Yang Fang , Qiu Zhaobin 
Published: February 2011

AbstractMiscibility and crystallization behaviors of biodegradable poly(butylene succinate‐co‐butylene terephthalate) (PBST)/poly(hydroxyl ether biphenyl A) (phenoxy) blends were investigated with various techniques in this work. PBST and phenoxy are completely miscible as evidenced by the single composition‐dependent glass transition temperature over the entire blend compositions. Nonisothermal melt crystallization peak temperature is higher in neat PBST than in the blends at a given cooling rate. Isothermal melt crystallization kinetics of neat and blended PBST was studied and analyzed by the Avrami equation. The overall crystallization rate of PBST decreases with increasing crystallization temperature and the phenoxy content in the PBST/phenoxy blends; however, the crystallization mechanism of PBST does not change. Moreover, blending with phenoxy does not modify the crystal structure but reduces the crystallinity degree of PBST in the PBST/phenoxy blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
High transmittance and environment‐friendly flame‐resistant optical resins based on poly(methyl methacrylate) and cyclotriphosphazene derivatives
Authors: Guo Ya‐Ni , Qiu Jin‐Jun , Tang He‐Qing , Liu Cheng‐Mei 
Published: February 2011

AbstractHighly transparent optical resins based on poly(methyl methacrylate) (PMMA) and two cyclotriphosphazene derivatives which acting as halogen‐free flame retardants were prepared. The refractive indices, visible light transmittance, water absorption, flame‐resistant characteristic, and the mechanical properties of the resins were studied. Comparing with pure PMMA, the as‐prepared resins with the two additives exhibited higher refractive index (nd), longer UV cutoff wavelength and better surface hardness. The water absorption of the resins was decrease with increasing of the additives. The visible light transmittance of all the samples adding Additive A was higher than 90%. When the weight ratio of additive/MMA was 20/100, the limiting oxygen index (LOI) of the samples were 26 (with Additive A) and 22 (with Additive B), respectively. The surface hardness was increased from HB to 2H with increasing the content of the additives, and the impact and the tensile strength changed little for the formulas of the additives lower than 30% by weight. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of porogenic solvent on the morphology, recognition and release properties of carbamazepine‐molecularly imprinted polymer nanospheres
Authors: Esfandyari‐Manesh Mehdi , Javanbakht Mehran , Atyabi Fatemeh , Badiei Alireza , Dinarvand Rassoul 
Published: February 2011

AbstractThis study focus on the effect of the porogenic solvent on the morphology, recognition, and drug release of carbamazepine‐molecularly imprinted polymer nanospheres prepared by precipitation polymerization. The scanning electron microscopy (SEM) images and Brunauer‐Emmett‐Teller (BET) analysis showed that molecularly imprinted polymer (MIP) prepared by acetonitrile exhibited a regular spherical shape at the nanoscale with a high degree of monodispersity, specific surface area of 242 m2 g−1, and pore volume of 1 mL g−1, while those using chloroform and toluene produced irregular polymer particles with low specific surface area and pore volume. MIP prepared by acetonitrile/chloroform (1 : 1, v/v) showed mediator texture properties compared to MIPs obtained by acetonitrile or chloroform. Results from saturation and displacement assays indicated that the imprinted nanospheres with binding capacity of 2.85 (mg CBZ/g polymer) had high specific affinity to CBZ in contrast to nonimprinted nanospheres (1.63 mg CBZ/g polymer). The imprinted nanospheres with 2.4 selectivity factor had good recognition to CBZ than analog template of oxcarbazepine. Moreover, release studies showed that 20% of loaded CBZ was released from the imprinted nanospheres within the initial 6 h, while another 80% of CBZ was released in the following 9 days. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology and electrical properties of polymethylmethacrylate/poly(styrene‐co‐acrylonitrile)/multi‐walled carbon nanotube nanocomposites
Authors: Lee Minho , Jeon Hyeonyeol , Min Byong Hun , Kim Jeong Ho 
Published: February 2011

AbstractNanocomposites of blends of polymethylmethacrylate (PMMA) and poly(styrene‐co‐acrylonitrile) (SAN) with multi‐walled carbon nanotubes (MWCNTs) were prepared by melt mixing in a twin‐screw extruder. The dispersion state of MWCNTs in the matrix polymers was investigated using transmission electron microscopy. Interestingly enough, in most of the nanocomposites, the MWCNTs were observed to be mainly located at SAN domains, regardless of the SAN compositions in the PMMA/SAN blend and of the processing method. One possible reason for this morphology may be the π–π interactions between MWCNTs and the phenyl ring of SAN. The shift in G‐band peak observed in the Raman spectroscopy may be the indirect evidence proving these interactions. The percolation threshold for electrical conductivity of PMMA/SAN/MWCNT nanocomposites was observed to be around 1.5 wt %. Nanocomposites with PMMA‐rich composition showed higher electrical conductivity than SAN‐rich nanocomposites at a fixed MWCNT loading. The dielectric constant measurement also showed composition‐dependent behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Osteoarthritis induction leads to early and temporal subchondral plate porosity in the tibial plateau of mice: An in vivo microfocal computed tomography study
Authors: Botter Sander M. , van Osch Gerjo J. V. M. , Clockaerts Stefan , Waarsing Jan H. , Weinans Harrie , van Leeuwen Johannes P. T. M. 
Published: February 2011

AbstractObjectiveIn osteoarthritis (OA), changes occur in both cartilage and subchondral bone. The subchondral bone plate facilitates normal cross‐talk between articular cartilage and trabecular subchondral bone, and adaptive changes in the plate due to OA may therefore disturb cross‐talk homeostasis. To investigate these changes over time, we examined the cartilage–subchondral bone interface using a combined approach of histologic analysis and in vivo microfocal computed tomography.MethodsSixteen‐week‐old male C57BL/6 mice (n = 32) received intraarticular injections of collagenase in 1 joint to induce instability‐related OA and received saline injections in the contralateral knee joint (control joint). At 2, 4, 6, 10, and 14 weeks after injection, changes in the tibial subchondral bone plate and subchondral trabeculae were analyzed.ResultsTwo weeks after injection, collagenase‐injected joints had significantly more cartilage damage and osteophytosis than did control joints. Osteoclast activity directly underneath the subchondral bone plate was significantly elevated in collagenase‐injected joints compared to control joints (mean ± SEM osteoclast surface/bone surface 11.07 ± 0.79% versus 7.60 ± 0.81%), causing the plate to become thinner and creating a large increase in subchondral bone plate porosity (mean ± SEM cumulative porosity volume 0.05 ± 0.04 × 10−3 mm3 in control joints versus 2.52 ± 0.69 × 10−3 mm3 in collagenase‐injected joints). Four weeks after injection, the previously formed perforations disappeared, coinciding with a significant rise in osteoblast activity in the subchondral trabecular bone in collagenase‐injected joints compared to control joints (mean ± SEM bone formation rate/bone surface 0.62 ± 0.13 μm3/μm2 per day versus 0.30 ± 0.03 μm3/μm2 per day).ConclusionThe current study is the first to provide quantitative longitudinal data on the dynamic changes in the subchondral bone plate after OA induction. The development of plate perforations may enhance mutual interaction between subchondral trabeculae, bone marrow cells, and the articular cartilage in OA.
The TEDS framework for assessing information systems from a human actors' perspective: Extending and repurposing Taylor's Value‐Added Model
Authors: Scholl Hans J. , Eisenberg Michael B. , Dirks Lee , Carlson Timothy S. 
Published: February 2011

AbstractDeveloped in the early 1980s—well before Internet and web‐based technologies had arrived—Taylor's Value‐Added Model introduced what is now better known as the human‐actors' needs perspective on information systems/information technology (IS/IT) artifacts. Taylor distinguished six top‐level criteria that mattered most to human actors when using IS/IT artifacts. We develop this approach further and present the TEDS framework as an analytical instrument for actor‐ and utilization‐specific evaluation of IS/IT artifacts as well as a practical tool for moderating and formulating design specifications. We use the empirical case of a comprehensive comparative professional sports team web site evaluation project to illustrate the power and versatility of the extended analytical framework.
Design of Interpenetrated Networks of Mesostructured Hybrid Silica and Nonconductive Poly(vinylidene fluoride)–Cohexafluoropropylene (PVdF–HFP) Polymer for Proton Exchange Membrane Fuel Cell Applications
Authors: Pereira Franck , Chan Alida , Vallé Karine , Palmas Pascal , Bigarré Janick , Belleville Philippe , Sanchez Clément 
Published: February 2011

AbstractOrganic–inorganic hybrid membranes of poly(vinylidene fluoride)–cohexafluoropropylene (PVdF–HFP) and mesostructured silica containing sulfonic acid groups were synthesized by using the sol‐gel process. These hybrid membranes were prepared by in situ co‐condensation of tetraethoxysilane and an organically modified silane (ormosil) by a self‐assembly route using organic surfactants as templates for tuning the architecture of the hybrid organosilica component. In this paper, we describe the elaboration and characterization of hybrid membranes all the way from the precursor solution to the evaluation of the fuel cell performances. These hybrid materials were extensively characterized by using NMR and IR spectroscopy, electron microscopy, or impedance spectroscopy so as to determinate their physicochemical and electrochemical properties. Even though the ion‐exchange capacity (IEC) was quite weak, the first fuel cell tests performed with these hybrid membranes show promising results relative to optimized Nafion 112 thanks to great water management of the silica inside the hydrophobic polymer.