bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biodegradable polymers. XI. Spectral, thermal, morphological, and biodegradability properties of environment‐friendly green plastics of soy protein modified with thiosemicarbazide
Authors: Nanda Prativa K. , Krishna Rao K. , Nayak Padma L. 
Published: December 2006

AbstractThe demand for biodegradable polymers produced from renewable natural resources continues to grow as environmental concerns increase. Biodegradable plastics derived from agricultural feedstock are a new generation of materials capable of reducing the environmental impact in terms of energy consumption and greenhouse effect in specific applications to perform as traditional/conventional plastics when in use and are completely biodegradable within a composting cycle through the action of living/micro‐organisms. The objective of this study is to examine the potentiality and performance pattern of soy protein isolate (SPI) resin, modified with various concentrations of thiosemicarbazide (TSC), as a thermoplastic to substitute some conventional petroleum‐based plastics. The spectral, thermal, morphological properties and the biodegradability of the modified resin have been investigated. The spectral studies indicate that TSC is not crosslinked with the protein moiety; rather, it acts as a modifier. Thermogravimetric analysis of the modified material has been followed using a computer analysis method (LOTUS package) developed by us for assigning the degradation mechanism. A number of equations have been used to evaluate the kinetic parameters. The degradation mechanism has been ascertained on the basis of the kinetic parameters. It is expected that, this environment‐friendly, fully biodegradable and sustainable TSC‐modified SPI green plastic could be commercially used for making molded products. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3134–3142, 2007
Preparation and properties of magnetorheological elastomers based on silicon rubber/polystyrene blend matrix
Authors: Wang Yinling , Hu Yuan , Gong Xinglong , Jiang Wanquan , Zhang Peiqiang , Chen Zuyao 
Published: December 2006

AbstractMagnetorheological (MR) elastomers, which are mainly composed of magnetic particles and elastic polymer, are a new kind of smart materials whose modulus can be controlled by changing the strength of magnetic fields. In this article, MR elastomers based on immiscible silicon rubber/polystyrene (SR/PS) blend matrix were fabricated successfully via cosolvent method and the MR effect, electric and mechanical properties, and the microstructures of the corresponding materials were studied. SEM studies showed that the dispersion of iron particles in blend matrix were different from that in single polymer, which could be further proved by the different electric conductivity. The MR effect of MR elastomers based on blend matrix varied with the different ratios of SR and PS, which was discussed in detail from the special dispersion of iron particles and of zero‐modulus of MR elastomers. In addition, the MR elastomers based on SR/PS blend matrix had enhanced mechanical properties, which made them more hopeful to be applied in practice. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3143–3149, 2007
Preparation and properties of cyanate ester modified by epoxy resin and phenolic resin
Authors: Lu Sheng‐Hua , Zhou Zhi‐Wei , Fang Li , Liang Guo‐Zheng , Wang Jie‐Liang 
Published: December 2006

AbstractStiff and brittle cyanate ester (CE) resin was modified by copolymerizing it with epoxy resin (ER) and phenolic resin (PR) to improve its toughness and flexibility. The cure process of the modified CE resin was characterized by gel time curves and differential scanning calorimetry curves. The Fourier transform infrared spectra of the modified CE resin showed its chemical structure during the curing process. The mechanical properties, thermal behavior, dielectric properties, and morphology of the modified CE resins were investigated. The results showed that an increase in epoxy and phenolic resins resulted in improved flexibility while maintaining thermal stability. When the mass ratio of CE/ER/PR was 70 : 15 : 15 (w/w), flexural strength and impact strength of the modified CE resin increased from 113.6 MPa and 5.2 kJ/m2 to 134.5 MPa and 16.7 kJ/m2, respectively. Little of the thermal stabilityand dielectric properties was sacrificed in the modification of the CE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3150–3156, 2007
Synthesis of novel sulfonium salts and cationic polymerization of epoxides and vinyl ether
Authors: Hyun Dong Hun , Patil Prashant , Kim Jun Young , Kim Tae Ho 
Published: December 2006

AbstractNovel 1‐methoxycarbonylethylmethylphenylsulfonium salts with nonnucleophilic anions, namely, hexafluorophosphate, hexafluoroantimonate, and tetrafluoroborate, were synthesized by the reaction of 1‐methoxycarbonylethylphenylsulfide and dimethyl sulfate followed by anion exchange with potassium hexafluorophosphate, sodium hexafluoroantimonate, and sodium tetrafluoroborate, respectively. The cationic polymerization (photopolymerization and thermal polymerization) of epoxy and vinyl ether monomers was carried out to demonstrate the applicability of the newly synthesized sulfonium salts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3157–3163, 2007
Performance of concretes produced with superplasticizer
Authors: Kılınçkale F. M. , Doǧan G. G. 
Published: December 2006

AbstractNowadays, additive chemical substances are used in the production of high‐performance concrete composites. These additives increase the fresh workability of concrete by decreasing the water/cement (W/C) ratio. The aim of this study was to examine the effects of water‐soluble polymers on concrete performance. For this purpose concretes with and without additives were produced with W/C values of 0.52, 0.56, and 0.60. Chemical admixtures such as naphthalene formaldehyde sulfonate (N), melamine formaldehyde sulfonate (S), and a hyperplasticizers admixture (a special type of melamine sulfonated polymer) (H) were used in concrete. The amounts of these admixtures were at a ratio of 0.3, 0.5, and 1.0 wt % of the cement's weight. Experiments assessing slump, VeBe, percentage of air, and unit weight were done for comparison with the test results of the characteristics of fresh concrete with and without admixtures. The compressive strength of concretes was determined at 7, 28, and 56 days. The effects of chemical admixtures were studied by comparing the properties of fresh and hardened concrete samples with and without admixtures. When the W/C ratios were 0.56, 0.60, and H was 1 wt %, the biggest slump was obtained and found to be 22 cm. Concrete with a W/C ratio of 0.52 and H of 1% has the highest compressive strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3214–3219, 2007
Effects of nanoclay on the properties of cardanol‐modified‐resol‐epoxy‐novolac composite material
Authors: Nguyen Le Huong , Nguyen Dac Thanh , La Thai Ha , Phan Kim Xuyen , Nguyen Thi Thanh Thao , Nguyen Huu Nieu 
Published: December 2006

AbstractA nanocomposite based on nanoclay and resol that was modified with cardanol, a natural alkyl phenol, shows improvement for the glass‐fiber‐reinforced epoxy‐composite system. Dispersion of the nanocomposite was investigated by X‐ray, showing good results obtained by the in situ polymerization method. The mechanical properties of the final composites were improved by doping a 6 wt% of nanoclay in cardanol‐modified‐resol (CMR) into the epoxy matrix. The results show that a 15 wt% of CMR in epoxy is a most suitable ratio. Using polyamide as a curing agent instead of other traditional systems, such as anhydrides or amines for epoxy resin, overcame important limitations, further allowing for improved processability. The overall composite performance was enhanced. Additionally, the thermal stability of the system was investigated by thermal gravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3238–3242, 2007
Influence of the initiator system on the spatial inhomogeneity in acrylamide‐based hydrogels
Authors: Orakdogen Nermin , Okay Oguz 
Published: December 2006

AbstractThe effect of the initiator system used in the gel preparation on the spatial inhomogeneity in poly(acrylamide) (PAAm) and poly(N,N‐dimethylacrylamide) (PDMA) hydrogels was investigated by static light scattering and elasticity measurements. The hydrogels were prepared by free‐radical crosslinking copolymerization of the monomers acrylamide (AAm) or N,N‐dimethylacrylamide (DMA) with N,N′‐methylenebisacrylamide as a crosslinker. Two different redox‐initiator systems, ammonium persulfate (APS)–N,N,N′,N′‐tetramethylethylenediamine (TEMED) and APS–sodium metabisulfite (SPS), were used to initiate the gelation reactions. Compared to the APS–TEMED redox pair, no significant scattered light intensity rise was observed during the crosslinking polymerization reactions initiated by the APS–SPS system. It was found that both PAAm and PDMA gels are much more homogeneous when the APS–SPS redox pair was used as the initiator. The results are explained by the formation of shorter primary chains as well as the delay of the gel point in APS–SPS initiated gel formation reactions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3228–3237, 2007
Macroporous chelating resins incorporating heterocyclic functional groups via hydrophilic PEG spacer arms. I. Synthesis and characterization
Authors: Ji Chunnuan , Qu Rongjun , Sun Changmei , Wang Chunhua , Xu Qiang , Sun Yanzhi , Li Chunxian , Guo Shuhua 
Published: December 2006

AbstractA series of novel chelating resins were synthesized by incorporating heterocyclic functional groups such as 2‐aminopyridine (AP), 2‐amino‐5‐methylthio‐1,3,4‐thiadizole (AMTZ), 2‐amino‐5‐ethyl‐1,3,4‐thiadizole (AETZ), and 2‐mercaptobenzothiazole (MBZ) into macroporous crosslinked polystyrene via a hydrophilic spacer arm of polyethylene glycol containing sulfur. Structures of the above‐mentioned resins were characterized by elemental analysis, Fourier transform‐infrared spectra (FTIR), ASAP‐2020 surface area and porosity analyzer, and scanning electron microscopy (SEM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3220–3227, 2007
Synthesis and characterization of alkali‐modified styrene‐maleic anhydride copolymer for dispersion of TiO2
Authors: Kumari Suman , Nigam Dhirendra , Agarwal Devendra , Nigam Indira 
Published: December 2006

AbstractA copolymer of styrene and maleic anhydride was synthesized by free radical polymerization at 80°C using N,N‐dimethylformamide (DMF) as solvent and benzoylperoxide as initiator. The monomer feed ratio of styrene to maleic anhydride was varied in the range of 1 : 1 : to 3 : 1. The polymer yield was found to decrease with increase in styrene in the feed. The molecular weight of copolymers which were formed by taking styrene to maleic anhydride ratio of 1 : 1, 2 : 1, and 3 : 1, as determined by Ostwald Viscometery were about 1862, 2015, and 2276 respectively. The acid values of abovementioned three copolymers were found to be 480, 357, and 295, respectively. The typical viscosity values of 20% solids in ammonical solution of copolymers formed by taking feed ratios of Sty : MAn as 1 : 1 and 2 : 1 were 26 and 136 cp, respectively. For the feed ratio 3 : 1, a gel was formed. The synthesized copolymers were hydrolyzed by alkalis, namely, NaOH, KOH, and NH4OH. The dispersing ability of hydrolyzed styrene‐maleic anhydride (SMA) copolymers for dispersion of titanium dioxide was studied. The modified SMA copolymers were found to be effective dispersants for TiO2. Among the three alkalis studied, the Sodium salts of SMA were found to give better dispersion. The copolymer having a 1 : 1 feed ratio showed the best dispersing ability for TiO2 particles among the three ratios studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3194–3205, 2007
Construction of a novel sensor based on electropolymerization of carmine for voltammetric determination of 4‐nitrophenol
Authors: Li Chunya 
Published: December 2006

Abstract4‐Nitrophenol (4‐NP) has been determined with voltammetric technique based on a novel sensor fabricated by electropolymerization of carmine on a glassy carbon electrode (GCE). An obvious reduction peak located at about −0.700 V and a couple of redox peaks that were not well‐defined were observed in the potential range of −1.00 to 0.600 V. Compared with its voltammetric behavior on a bare GCE, the reduction peak potential shifted positively and the peak current increased significantly. All experimental parameters were optimized and linear sweep voltammetry was proposed for its determination. In the optimal conditions, the reduction peak current was proportional to the 4‐NP concentration over the concentration range from 5.00 × 10−8 to 1.00 × 10−5 mol L−1, and the detection limit was 1.00 × 10−8 mol L−1 after 200 s of accumulation. The high sensitivity and selectivity of the sensor was demonstrated by its practical application for the determination of trace amounts of 4‐NP in lake water. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3271–3277, 2007
Master curve and time–temperature–transformation cure diagram of lignin–phenolic and phenolic resol resins
Authors: Alonso M. V. , Oliet M. , García J. , Rodríguez F. , Echeverría J. 
Published: December 2006

AbstractThe aim of this work is to generate both a master curve of resol resins based on the time–temperature superposition principle and their TTT cure diagrams. The samples used for this purpose were lignin–phenolic and phenol–formaldehyde resol resins. A TMA technique was employed to study the gelation of resol resins. In addition, a DSC technique was employed to determine the kinetic parameters through the Ozawa method, which allowed us to obtain isoconversional curves from the data fit to the Arrhenius expression. Establishing the relationship between the glass‐transition temperature and curing degree allowed the determination of the vitrification lines of the resol resins. Thus, using the experimental data obtained by TMA and DSC, we generated a TTT cure diagram for each of resins studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3362–3369, 2007
Isothermal crystallization kinetics in binary miscible blend of poly(ε‐caprolactone)/tetramethyl polycarbonate
Authors: Madbouly Samy A. 
Published: December 2006

AbstractThe crystallization kinetics of pure poly(ε‐caprolactone) (PCL) and its blends with bisphenol‐A tetramethyl polycarbonate (TMPC) was investigated isothermally as a function of composition and crystallization temperature (Tc) using differential scanning calorimetric (DSC) and polarized optical microscope techniques. Only a single glass‐transition temperature, Tg, was determined for each mixture indicating that this binary blend is miscible over the entire range of composition. The composition dependence of the Tg for this blend was well described by Gordon–Taylor equation with k = 1.8 (higher than unity) indicating strong intermolecular interaction between the two polymer components. The presence of a high Tg amorphous component (TMPC) had a strong influence on the crystallization kinetics of PCL in the blends. A substantial decrease in the crystallization kinetics was observed as the concentration of TMPC rose in the blends. The crystallization half‐time t0.5 increased monotonically with the crystallization temperature for all composition. At any crystallization temperature (Tc) the t0.5 of the blends are longer than the corresponding value for pure PCL. This behavior was attributed to the favorable thermodynamics interaction between PCL and TMPC which in turn led to a depression in the equilibrium melting point along with a simultaneous retardation in the crystallization of PC. The isothermal crystallization kinetics was analyzed on the basis of the Avrami equation. Linear behavior was held true for the augmentation of the radii of spherulites with time for all mixtures, regardless of the blend composition. However, the spherulites growth rate decreased exponentially with increasing the concentration of TMPC in the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3307–3315, 2007
Reduction in orofacial clefts following folic acid fortification of the U.S. grain supply
Authors: Yazdy Mahsa M. , Honein Margaret A. , Xing Jian 
Published: December 2006

AbstractBACKGROUND:Folic acid fortification in the United States became mandatory January 1, 1998, to reduce the occurrence of neural tube defects (NTDs). We evaluated the impact of folic acid fortification on orofacial clefts using United States birth certificate data for 45 states and the District of Columbia.METHODS:Prevalence ratios (PRs) were calculated comparing orofacial cleft prevalence among births prefortification (1/1990–12/1996) and postfortification (10/1998–12/2002), based on fortification status at conception. The JoinPoint Regression Program and exponentially weighted moving average charts (EWMA) were used to assess the timing of any statistically significant changes in prevalence. Data were stratified by maternal race/ethnicity, age, smoking, and timing of prenatal care.RESULTS:Orofacial clefts declined following folic acid fortification (PR = 0.94; 95% CI: 0.92–0.96). The EWMA chart flagged a significant decrease in the fourth quarter of 1998. The JoinPoint graph had one change in slope, with a significant quarterly percent change (−0.34) between 1996 and 2002. The decline in orofacial clefts occurred in non‐Hispanic Whites but not other racial/ethnic groups, nonsmokers but not women who reported smoking during pregnancy, and women who received prenatal care in the first trimester but not women who began receiving care later in pregnancy.CONCLUSION:Folic acid fortification in the United States was associated with a small decrease in orofacial cleft prevalence, with the timing of the decline consistent with the introduction of fortification. The decline is much smaller than that observed for NTDs, but nonetheless suggests an additional benefit of this public health intervention. Birth Defects Research (Part A) © 2006 Wiley‐Liss, Inc.
Molecular profiles of mitogen activated protein kinase signaling pathways in orofacial development
Authors: Singh Saurabh , Yin Xiaolong , Pisano M. Michele , Greene Robert M. 
Published: December 2006

AbstractBACKGROUND:Formation of the mammalian orofacial region involves multiple signaling pathways regulating sequential expression of and interaction between molecular signals during embryogenesis. The present study examined the expression patterns of members of the MAPK family in developing murine orofacial tissue.METHODS:Total RNA was extracted from developing embryonic orofacial tissue during gestational days (GDs) 12–14 and used to prepare biotinylated cDNA probes, which were then denatured and hybridized to murine MAPK signaling pathways gene arrays.RESULTS:Expression of a number of genes involved in the (ERK1/2) cascade transiently increased in the embryonic orofacial tissue over the developmental period examined. Numerous members of the SAPK/JNK cascade were constitutively expressed in the tissue. Genes known to play a role in p38 MAPK signaling exhibited constitutive expression during orofacial development. Western blot analysis demonstrated that ERK2/1, p38, and SAPK/JNK kinases are present in embryonic orofacial tissue on each of GD 12, 13, and 14. By using phospho‐specific antibodies, active ERK was shown to be temporally regulated during orofacial development. Minimal amounts of active p38 and active SAPK/JNK were detected in orofacial tissue during GDs 12–14.CONCLUSIONS:Our study documents specific expression patterns of genes coding for proteins belonging to the ERK1/2, p38, and SAPK/JNK MAPK families in embryonic orofacial tissue. We also demonstrate that active, phosphorylated forms of ERK1/2 only were detected in the embryonic tissue investigated, suggesting a more central role for members of this family in embryonic orofacial development. Birth Defects Research (Part A) © 2006 Wiley‐Liss, Inc.
Rhabdomyomatous hamartomata of the pharyngeal region with bilateral microtia and aural atresia: A new association?
Authors: Adam Margaret P. , Abramowsky Carlos R. , Brady April N. , Coleman Karlene , Todd N. Wendell 
Published: December 2006

AbstractBACKGROUND: Bilateral microtia with aural atresia is rare. Rhabdomyomatous hamartomata containing salivary tissue, situated bilaterally and symmetrically simulating the palatine (faucial) tonsils, has apparently not been reported. We present the combination of these findings in two unrelated patients. CASES: In the first case, the patient was exposed prenatally to 13‐cis‐retinoic acid (isotretinoin) and has typical features of this exposure, including bilateral microtia with aural atresia and bilateral 7th nerve palsies. Due to symptoms of obstructive sleep apnea, patient 1 had a “tonsillectomy” and adenoidectomy. Histopathologic studies demonstrated rhabdomyomatous hamartomata containing salivary and striated muscle tissue in place of the palatine tonsils. In the second case, the patient had been prenatally exposed to alcohol, cocaine, and marijuana. He has been noted to have developmental delay and behavioral issues in addition to bilateral microtia with aural atresia. “Tonsillectomy” and adenoidectomy were performed to alleviate chronic upper respiratory infections and snoring. Again, histopathologic studies of the tissue submitted as “tonsil” demonstrated rhabdomyomatous hamartomata containing salivary and muscle tissue. Although an extended banded karyotype and subtelomere panel were normal, a genetic etiology for the second patient's features cannot be excluded. CONCLUSIONS: We hypothesize that the findings of bilateral microtia with aural atresia and rhabdomyomatous hamartomata containing salivary and muscle tissue in the area of the palatine tonsils may represent a newly recognized association, which may have a teratogenic and/or genetic etiology. Birth Defects Research (Part A), 2007. © 2006 Wiley‐Liss, Inc.
Measuring organizational performance: beyond the triple bottom line
Authors: Hubbard Graham 
Published: December 2006

AbstractMeasuring organizational performance is difficult, especially when what has to be measured keeps changing. Sustainability concepts have dramatically widened the scope of measurement options and leading organizations are grappling with sustainability reporting, but there is no sign of consensus on a common reporting standard and the competing frameworks are impossibly complex. This paper recognizes that measuring sustainable performance has to be conceptually based but simplified to be practically useful. It proposes a stakeholder‐based, Sustainable Balanced Scorecard (SBSC) conceptual framework coupled with a single‐measure Organizational Sustainability Performance Index to integrate the measures in the SBSC. The Index helps make sustainable organizational performance measurable and accessible to stakeholders. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.