bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear dimensional changes of denture base and hard chair‐side reline resins after disinfection
Authors: Gonçalves Alessandro Ribeiro , Machado Ana Lucia , Giampaolo Eunice Teresinha , Pavarina Ana Cláudia , Vergani Carlos Eduardo 
Published: July 2006

AbstractObjectivesThis study evaluated the effect of disinfection by immersion in sodium perborate (50°C/10 min) or microwave irradiation (650 W/6 min) on the linear dimensional change (LDC) of four reline resins (Kooliner‐K, New Truliner‐N, Tokuso Rebase Fast‐T, Ufi Gel Hard‐U) and one heat‐polymerizing denture base resin (Lucitone 550‐L).MethodsSpecimens (50.0 mm diameter, 0.5 mm thickness) were made using a split mold with reference points, and divided into two controls and four test groups (n = 8). The distances between the points were measured on the mold (baseline readings), and compared to those obtained from the specimens after: polymerization or immersion in water (37°C) for 7 days (controls); 2 or 7 cycles of disinfection by immersion or microwave irradiation.ResultsThe two‐way ANOVA and Tukey's test (α = 0.05) showed that microwave disinfection significantly increased the mean LDC of materials L (−1.43%), N (−1.27%) and K (−1.06%). Material N also exhibited a significant increase in LDC after two cycles of chemical disinfection (−0.73%). For U (−0.47%) and T (−0.21%) materials, no significant changes in LDC were found.ConclusionsMicrowave disinfection increases the shrinkage of materials L, N, and K. The dimensional stability of resins U and T was not affected by the disinfection methods evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1821–1826, 2006
Thermal and mechanical properties of poly(trimethylene terephthalate) (PTT)/cationic dyeable poly(trimethylene terephthalate) (CD‐PTT) polyblended fibers
Authors: Hsiao Kai‐Jen , Lee Shu‐Pyng , Kong Dan‐Cheng , Chen Frank L. 
Published: July 2006

AbstractPoly(trimethylene terephthalate) (PTT) and cationic dyeable poly(trimethylene terephthalate) (CD‐PTT) were extruded (in the proportions of 80:20, 60:40, 40:60, and 20:80) from one melt twin‐screw extruder to prepare four PTT/CD‐PTT polyblended fibers. The molar ratio of 5‐sodium sulfonate dimethyl isophthalate (5‐SSDMI) for CD‐PTT polymer was 2%. This study investigated the thermal and mechanical properties of PTT/CD‐PTT polyblended fibers using gel permeation chromatograph, differential scanning calorimetry (DSC), thermogravimetric analysis, potentiometer, a rheometer, the density gradient, wide‐angle X‐ray diffraction, extension stress–strain measurement, and scanning electron microscope (SEM). Melting behavior of PTT/CD‐PTT polyblended polymers exhibited positive‐deviation blends, and the blend of PTT/CD‐PTT between 60:40 and 40:60 showed a maximum value of the melt viscosity. Experimental results from the DSC indicated that PTT and CD‐PTT molecules formed a miscible system. The tenacity of PTT/CD‐PTT polyblended fibers declined as the 5‐SSDMI content increased. Crystallinities and densities of PTT/CD‐PTT polyblended fibers were also found decrease as the 5‐SSDMI content increased. The surface of PTT/CD‐PTT polyblended fibers exhibited a uniform morphology, from the SEM observation. It indicated that PTT and CD‐PTT polymers were identified to be a miscible system. Though there is a good interfacial adhesion between PTT and CD‐PTT polymer, the mechanical properties of PTT/CD‐PTT ployblended fibers were largely affected by the 5‐SSDMI content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1008–1013, 2006
Superabsorbent polymeric materials. XIII. Effect of oxyethylene chain length on water absorbency for the sodium acrylate and poly(ethylene glycol) methyl ether acrylate (PEGMEAn) copolymeric gels
Authors: Lee Wen‐Fu , Yang Lin‐Gi 
Published: July 2006

AbstractIn a previous study, we prepared a series of xerogels based on sodium acrylate (NaA) and 2‐hydroxyethyl methacrylate (HEMA, OE = 1) or poly(ethylene glycol) methacrylate (PEGMA, OE = 6) with different oxyethylene (OE) units. The effect of the contents of HEMA and PEGMA in the copolymeric gel on the swelling behavior in deionized water and various saline solutions was studied. Their results showed that the water absorbencies for these two series gels were effectively improved by adding a small amount of HEMA or PEGMA. In this article, a series of novel xerogels based on NaA and hydrophilic monomer poly(ethylene glycol) methyl ether acrylate (PEGMEAn), which was synthesized from acryloyl chloride and poly(ethylene glycol) monomethyl ether with three oxyethylene (OE = 9, 16, 45) chain lengths, were prepared by inverse suspension polymerization. The effects of OE chain length in the copolymeric gel on the water absorption behavior and initial absorption rate for the present xerogels were investigated. Results showed that adding a small amount of PEGMEAn could effectively increase the water absorbency of the gels. In addition, the water absorbency decreased with an increase of the OE chain length in PEGMEAn. The initial absorption rate for the present copolymeric gels increased with increasing OE chain length in PEGMEAn and the content of PEGMEAn in the copolymeric gels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 927–934, 2006
Application of radio frequency glow discharge plasma for enhancing adhesion bonds in polymer/polymer joints
Authors: Lapèíková B. , Lapèík L. , Smolka P. , Dlabaja R. , Hui D. 
Published: July 2006

AbstractIt was found in this study, that air radio frequency glow discharge (rfGD) plasma is increasing surface roughness and is enhancing wettability of poly(propylene) (PP), poly(ethylene) (PE), and poly(carbonate) (PC). As an addition, the increased surface microhardness of PP and PE was found. Results indicate that rfGD air plasma treatment is very effective tool for improvement of adhesive properties of studied polymers as tested on single lap and double lap joints. The value of maximum load rise from 107 to 1926 N (approximately 18‐fold increase) for 20‐min‐treated PE and from 314 to 834 N (approximately three‐fold increase) for PP. Artificial accelerated ageing rapidly decreased the quality of adhesive joint. The value of maximum load decreased from 1926 to 221 N (approximately nine‐fold decrease) in the case of 20‐min‐treated PE. This result indicates that the ageing of the adhesive joint of plasma treated polymers can be a limitation factor in the possible application of the final component because of the extremely high loss of its initially‐enhanced mechanical properties. However, the strength of the thus prepared joints was higher in comparison to the plasma nontreated virgin samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1827–1833, 2006
Dynamic rheological behavior of polypropylene melts with pulsatile pressure flow in a dynamic capillary rheometer
Authors: He Guang Jian , Qu Jin Ping , Chun Yin Xiao 
Published: July 2006

AbstractA self‐made dynamic capillary rheometer (DCR) was designed to investigate the dynamic viscoelastic characteristic of polypropylene (PP) melt during the pulsatile pressure extrusion. A vibration force field was parallel superposed upon steady shear flow in this DCR by means of a vibration driven piston. During the pulsatile pressure extruding process in DCR, the PP melt displayed apparent viscoelasticity. The experiment results proved the pressure pulsatile extrusion could reduce the viscosity of polymer melts effectively. The phase difference between the shear stress and the shear rate decreased with the superposed vibration. But, at large amplitude conditions, the viscosity has an increasing tendency. This maybe illuminated that large amplitude could be harmful for the vibration‐assistant polymer processing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1834–1838, 2006
Syntheses and properties of polyimides derived from diamines containing 2,5‐disubstituted pyridine group
Authors: Xia Aixiang , Guo Haiquan , Qiu Xuepeng , Ding Mengxian , Gao Lianxun 
Published: July 2006

AbstractA series of novel homo‐ and copolyimides containing pyridine units were prepared from the heteroaromatic diamines, 2,5‐bis (4‐aminophenyl) pyridine and 2‐(4‐aminophenyl)‐5‐aminopyridine, with pyromelltic dianhydride (PMDA), and 3,3′, 4,4′‐biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two‐step thermal imidizaton method. The poly(amic acid) precursors have inherent viscosities of 1.60–9.64 dL/g (c = 0.5 g/dL in DMAC, 30°C) and all of them can be cast and thermally converted into flexible and tough polyimide films. All of the polyimides show excellent thermal stability and mechanical properties. The polyimides have 10% weight loss temperature in the range of 548–598°C in air. The glass transition temperatures of the PMDA‐based samples are in the range of 395–438°C, while the BPDA‐based polyimides show two glass transition temperatures (Tg1 and Tg2), ranging from 268 to 353°C and from 395 to 418°C, respectively. The flexible films possess tensile modulus in the range of 3.42–6.39 GPa, strength in the range of 112–363 MPa and an elongation at break in the range of 1.2–69%. The strong reflection peaks in the wide‐angle X‐ray diffraction patterns indicate that the polyimides have a high packing density and crystallinity. The polymer films are insoluble in common organic solvents exhibiting high chemical resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1844–1851, 2006
Preparation of porous carbon microspheres
Authors: Lu Yonggen , Yang Changling , Rong Haiqin , Pan Ding 
Published: July 2006

AbstractPorous carbon microspheres with good morphology, high yield, and controllable particle size were prepared from phenolic resin. The particle size and pore structure of the carbon microspheres were mainly inherited from their precursors, resol microspheres, which were made through curing emulsified resol in water at 120°C under saturated pressure. The average particle size and specific surface area of the porous carbon microspheres was related to the concentration of resol and polyvinyl alcohol along with the heating program. The carbonization yield to 700°C was 55 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 798–803, 2006
Using maleic anhydride grafted poly(lactic acid) as a compatibilizer in poly(lactic acid)/layered‐silicate nanocomposites
Authors: Petersson L. , Oksman K. , Mathew A. P. 
Published: July 2006

AbstractThe goal of this work was to prepare exfoliated poly(lactic acid) (PLA)/layered‐silicate nanocomposites with maleic anhydride grafted poly(lactic acid) (PLA–MA) as a compatibilizer. Two different layered silicates were used in the study: bentonite and hectorite. The nanocomposites were prepared by the incorporation of each layered silicate (5 wt %) into PLA via solution casting. X‐ray diffraction of the prepared nanocomposites indicated exfoliation of the silicates. However, micrographs from transmission electron microscopy showed the presence of intercalated and partially exfoliated areas. Tensile testing showed improvements in both the tensile modulus and yield strength for all the prepared nanocomposites. The results from the dynamic mechanical thermal analysis showed an improvement in the storage modulus over the entire temperature range for both layered silicates together with a shift in the tan δ peak to higher temperatures. The effect of using PLA–MA differed between the two layered silicates because of a difference in the organic treatment. The bentonite layered silicate showed a more distinct improvement in exfoliation and an increase in the mechanical properties because of the addition of PLA–MA in comparison with the hectorite layered silicate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1852–1862, 2006
Adsorption and antibacterial activity of silver‐dispersed carbon aerogels
Authors: Zhang Shuting , Wu Dingcai , Wan Lin , Tan Haibing , Fu Ruowen 
Published: July 2006

AbstractSilver‐dispersed carbon aerogels (Ag/CAs) were obtained by the direct immersion of organic aerogels in aqueous AgNO3 solutions and then carbonization of the resulting material under a nitrogen atmosphere. The adsorption and antibacterial activity of Escherichia coli and Staphylococcus aureus on Ag/CAs were studied by the measurement of the amount of viable bacteria in suspensions and scanning electron microscopy (SEM) observations. The adsorbed amount of bacteria on samples without silver increased with an increase in the carbonization temperature and contact time. SEM studies showed that the adsorption capacity of Ag/CAs decreased with an increase in the silver content; this was considered to be mainly due to the dissolution behavior of bacteria by silver ions. The antibacterial test showed that 2.5 mg of Ag/CAs with more than 3.6% Ag could inhibit the growth of 105 cfu/mL E. coli in 10 mL of a Mueller–Hinton broth culture, but in the case of S. aureus, 10‐mg samples just got the same antibacterial effect. An antibacterial persistency test showed that 25 mg of Ag/CAs with 6.5% Ag could kill 50 mL of 105 cfu/mL E. coli eight times. These results indicate that Ag/CAs possess strong and long‐term antibacterial activity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1030–1037, 2006
Oscillatory measurements for salad dressings stabilized with modified starch, xanthan gum, and locust bean gum
Authors: Dolz M. , Hernández M. J. , Delegido J. 
Published: July 2006

AbstractThe rheological properties of low‐oil‐content food emulsions were analyzed with oscillatory tests within the linear viscoelastic region. The formulations of these salad dressings usually include modified starch because of its low cost and the special creamy texture that it affords. The combination of starch with other natural gums may improve the quality of the product. A reference emulsion containing 4% modified starch and four other formulations in which the starch was partially replaced by xanthan gum (0.4%), locust bean gum (0.4%), and synergistic blends of these gums (0.03 + 0.03% or 0.1 + 0.1%) were formulated. Gels before emulsification were studied for comparative purposes. All systems showed weak gel behavior. An empirical equation fitting the storage and loss modulus dependence on the frequency was applied. The loss tangent allowed us to compare the viscoelastic character of all the systems. The complex viscosity followed the power law in all cases, and the generalized Cox–Merz rule was applied. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 897–903, 2006
Effect of the processing molding temperature on the crystalline structure and properties of acrylonitrile‐butadiene rubber/trinylon thermoplastic vulcanizates
Authors: He Chunjiang , Zou Hua , Zhao Suhe 
Published: July 2006

AbstractThe effect of the processing molding temperature on the properties and crystalline structure of acrylonitile‐butadiene rubber (NBR)/nylon 6,66,1010 (trinylon) thermoplastic vulcanizates (TPV) was studied. With decreasing molding temperature, the stress at 100% and elongation at break of TPV changed slightly, and the solvent resistance of TPV improved. The best conditions for processing molding were 170°C and 12 min. The crystalline structure of the nylon continuous phase in TPV was investigated by X‐ray diffraction, polarized optical microscopy, and differential scanning calorimetry. The results show that the crystalline structure of the nylon phase in TPV was more perfect/orderly and formed α‐crystalline structure at a processing molding temperature of 170°C. Therefore, the oil resistance of NBR/trinylon TPV clearly improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1374–1379, 2006
Characterization of 25 tropical hardwoods with Fourier transform infrared, ultraviolet resonance Raman, and 13C‐NMR cross‐polarization/magic‐angle spinning spectroscopy
Authors: Nuopponen Mari H. , Wikberg Hanne I. , Birch Gillian M. , Jääskeläinen Anna‐Stiina , Maunu Sirkka L. , Vuorinen Tapani , Stewart Derek 
Published: July 2006

AbstractTwenty‐five tropical hardwoods from Ghana were examined with Fourier transform infrared (FTIR), ultraviolet resonance Raman (UVRR), and 13C‐NMR cross‐polarization/magic‐angle spinning spectroscopy. FTIR and UVRR spectral data were subjected to principal component analysis, whereas four selected samples exhibiting large structural and compositional variation were investigated in more detail by NMR spectroscopy. The acetyl bromide lignin and α‐cellulose contents of the samples and the amount of acetone‐soluble substances were also determined. The most prominent principal components of the FTIR spectral model separated samples mainly due to the variations in lignin structures and carbohydrate contents and the amount and type of carbonyl structures, whereas UVRR spectral data distinguished between various aromatic and other unsaturated structures. The presence of condensed lignin/tannin‐type structures were detected from UVRR and FTIR loading line plots of the minor principal components. Condensed tannins were also observed in the dipolar dephasing NMR spectra. Furthermore, the NMR results showed variations in the amount of crystalline cellulose and hemicelluloses and in the syringyl/guaiacyl proportions in lignin. Both NMR and FTIR data suggest that in most cases, a higher amount of guaiacyl units correlated with higher levels of acetyl bromide lignin and better bioresistance of the samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 810–819, 2006
Electrochemical copolymerization of carbazole and 3‐methylthiophene
Authors: Nie Guangming , Xu Jingkun , Zhang Shusheng , Cai Tao , Han Xuejun 
Published: July 2006

AbstractThe copolymerization of carbazole (CZ) and 3‐methylthiophene (3MeT) was successfully performed electrochemically in freshly distilled boron trifluoride diethyl etherate by direct anodic oxidation of the monomer mixtures, although the oxidation potentials of CZ and 3MeT were quite different. The electrochemical properties of the copolymers were studied with cyclic voltammetry. The influence of the applied polymerization potential on the synthesis of the copolymers was investigated. The higher potential favored the incorporation of 3MeT units into the copolymers. The insertion of 3MeT units into polycarbazole (PCZ) was helpful in improving the conductivity of PCZ. The novel copolymers had the advantages of both PCZ and poly(3‐methylthiophene), that is, good redox activity, good thermal stability, and high conductivity. The structure and morphology of the copolymers were investigated with ultraviolet–visible, infrared spectroscopy, thermal analysis, and scanning electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1877–1885, 2006
In vitro comparative hemostatic studies of chitin, chitosan, and their derivatives
Authors: Janvikul Wanida , Uppanan Paweena , Thavornyutikarn Boonlom , Krewraing Jirawat , Prateepasen Rujiporn 
Published: July 2006

AbstractThe effects of chitin, chitosan, and their derivatives on in vitro human blood coagulation and platelet activation were comparatively studied. The coagulation was assessed by the measure of the whole blood clotting time (WHBCT) and plasma recalcification time (PRT). The tested materials were chitin, chitosan, partially N‐acetylated chitosan (PNAC), N,O‐carboxymethylchitosan (NOCC), N‐sulfated chitosan, N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride, and SPONGOSTAN® standard (a positive control). The results revealed that the WHBCTs of whole blood mixed with chitin, chitosan, NOCC, or SPONGOSTAN® standard were significantly decreased with respect to that of the pure whole blood (a blank control) (P < 0.05), while the WHBCT value of whole blood mixed with PNAC was not significantly reduced. However, the presence of PNAC significantly lowered the PRT value, similar to the addition of chitin, NOCC, or SPONGOSTAN® standard. Chitosan was found to reduce PRT, but not significantly. In the platelet adhesion and activation studies, the morphology of platelets adherent to the film surfaces of tested materials was examined using a scanning electron microscopic technique. Because of their effective coagulation activites, chitosan, PNAC, and NOCC were further evaluated to determine how platelets behaved when in contact with these film samples for given periods. It was found that NOCC activated platelets most effectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 445–451, 2006
Polymer blends of epoxy resin and epoxidized natural rubber
Authors: Chuayjuljit S. , Soatthiyanon N. , Potiyaraj P. 
Published: July 2006

AbstractThe aim of this research was to investigate the behaviors of epoxy resin blended with epoxidized natural rubber (ENR). ENRs were prepared via in situ epoxidation method so that the obtained ENRs contained epoxide groups 25, 40, 50, 60, 70, and 80 mol %. The amounts of ENRs in the blends were 2, 5, 7, and 10 parts per hundred of epoxy resin (phr). From the results, it was found that the impact strength of epoxy resin can be improved by blending with ENRs. Tensile strength and Young's modulus were found to be decreased with an increasing amount of epoxide groups in ENR and also with an increasing amount of ENR in the blends. Meanwhile, percent elongation at break slightly increased when ENR content was not over 5 phr. In addition, flexural strength and flexural modulus of the blends were mostly lower than the epoxy resin. Scanning electron microscope micrograph of fracture surface suggested that the toughening of epoxy resin was induced by the presence of ENR globular nodules attached to the epoxy matrix. TGA and DSC analysis revealed that thermal decomposition temperature and glass transition temperature of the samples were slightly different. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 452–459, 2006
Degradation characteristics of poly(ϵ‐caprolactone)‐based copolymers and blends
Authors: Huang Ming‐Hsi , Li Suming , Hutmacher Dietmar W. , Coudane Jean , Vert Michel 
Published: July 2006

AbstractThe hydrolytic degradation of various bioresorbable copolymers and blends derived from ϵ‐caprolatcone, D,L‐lactide and poly(ethylene glycol) (PEG) was investigated at 37°C in a pH 7.4 phosphate buffer. Poly(ϵ‐caprolatcone) (PCL) followed a slow degradation profile due to its hydrophobicity and crystallinity. The hydrophilicity and degradability of the materials can be improved by copolymerization with PEG and/or poly‐(D,L‐lactide) (PLA). Homogenous degradation was shown in the cases of PCL, PCL/PEG copolymers and their blends, whereas PLA‐containing copolymers followed a heterogenous degradation due to internal autocatalysis. It was also shown that PCL‐based materials gradually turned to PCL‐enriched residues during degradation due to preferential hydrolysis of PLA segments and to diffusion of soluble species such as PLA oligomers and detached PEG blocks bearing short PLA segments. The results are discussed in comparison with literature data. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1681–1687, 2006