bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soft PVC foams: Study of the gelation, fusion, and foaming processes. I. Phthalate ester plasticizers
Authors: Zoller Agnes , Marcilla Antonio 
Published: March 2011

AbstractThe use of foamed plastics gains more and more interest every day. Flexible poly(vinyl chloride) (PVC) foams have excellent mechanical properties and low price, thus their application is extensive. Foams are produced from plastisols, which are based on the suspension of the PVC resin in a plasticizer. Phthalates are the most used plasticizers in flexible PVC foam formation. In this study, we have studied the influence of the phthalate ester‐type plasticizers on the foaming process and the quality of the foams obtained from the corresponding plastisols. For the plastisols prepared with the nine phthalate plasticizers considered, we have studied and discussed the complex and extensional viscosities; the thermal behavior (DSC) including the decomposition of the chemical blowing agent, and the foam production by rotational molding. In addition, we have characterized the foams obtained by thermomechanical analysis, density, and bubble size distribution. As expected, clear correlations have been obtained between the molecular weight and structure of the plasticizer with the rheological behavior of the plastisols. The knowledge of the gelation and fusion processes and evolution of the extensional viscosity of the plastisols combined with the study of the thermal decomposition of the blowing agent in each plastisol allows for better understanding of the complex dynamic behavior of these foaming systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The graft copolymerization of corn starch by microwave irradiation with rheological phase reaction
Authors: Da‐Wei Han , Jian‐Kun Wang , Hai‐Rong Lv , Ming‐Ming Xu 
Published: March 2011

AbstractThe corn starch was grafted by microwave irradiation with rheological phase reaction, to meet the sizing requirements of polyester/cotton blended yarn and avoid the disadvantages of corn starch size including brittle, hard, and size shedding. On the basis of the damping characteristics of corn starch film and the polarity of grafting monomer, the grafting effect of grafted corn starch was researched by using infrared spectroscopy, SEM, rotary viscometer, and thermomechanical analyzer. The results showed that both hydrophilic groups and hydrophobic groups were introduced in the molecular chains of grafted corn starch. The storage modulus of grafted corn starch film reached 285–315 MPa, being four times higher than that of nongrafted corn starch film. Compared with corn starch sizing, the viscosity of grafted corn starch sizing decreased 62.5%. Furthermore, through analyzing grafting law and establishing regression equation, it was indicated that the irradiation time and initiator content influenced the grafting ratio of grafted starch significantly. The grafting ratio could reach 19.57%, when the irradiation time and initiator content were selected with 3.5 min and 4.55%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation of raspberry‐shaped styrene‐butadiene‐methyl acrylate‐acrylic acid latex particles by emulsion polymerization followed by alkali/heating method
Authors: Wan Qichun , Li Yongfu , Todd Clifford , Harris Joe , Nicholson Dwayne , Chaput Bruce 
Published: March 2011

AbstractMonodispersed raspberry‐shaped polystyrene‐butadiene‐methyl acrylate‐acrylic acid particles were made by semi‐batch emulsion polymerization followed by alkali and heat treatment. The particle sizes and size distributions were studied by hydrodynamic chromatography and transmission electronic microscopy. The morphology of the particles was observed by SEM, cryo‐SEM, and TEM. Treatment temperature was found to have a significant impact on the particle size and morphology of the treated latexes. Higher temperatures lead to larger particle sizes and more discernible raspberry domains with sizes around 50 nm on the particle surfaces. Higher levels of alkali did not significantly change the particle size but did increase the total titratable acid amount, presumably due to the hydrolysis of methyl acrylate during the treatment. GPC results showed that higher amount of oligomers or polymers are produced in the serum for the heat‐treated latexes. Divinylbenzene crosslinking agent at the levels of 0.05–3% limited the particle expansion and decreased the serum acid. A possible mechanism of raspberry particle formations was proposed, which involves migration of hydrophilic and hydrophobic species during the heat treatment. Lastly, potential applications for raspberry particles in paper coating were explored. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Reinforcement of Si3N4 nanoparticles in polypropylene single fibers through melt extrusion process and their properties
Authors: Rangari Vijaya K. , Shaik Yousuf M. , Mohammad Ghouse M. , Jeelani Shaik 
Published: March 2011

AbstractWe have successfully aligned/dispersed the rod and spherical‐shaped Si3N4 nanoparticles in the polypropylene (PP) fibers through melt extrusion process to fabricate polymer nanocomposite (PNC) single fibers. The alignment/dispersion of Si3N4 nanoparticles in PP/Si3N4 PNC fibers has been carried out in a systematic manner to produce uniform single fibers. The PNC fibers were first uniformly stretched and stabilized using a two‐set Godet machine. The as‐extruded single PNC fibers were tested for their thermal and tensile properties. The test results of PNC fibers were compared to neat PP polymer single fibers fabricated using the same procedure as PNC fibers. These results show that the PNC fibers are much (307%) higher in tensile strength and modulus (>1000%) when compared with the neat PP polymer single fibers. The field emission scanning electron microscope results clearly show the alignment of rod‐Si3N4 nanoparticles in polymer matrix. The differential scanning calorimetry results show ∼ 12% increase in crystallinity for rod‐Si3N4 PNCs when compared with the neat PP single fibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Crystallization of isotactic polypropylene in the presence of a β‐nucleating agent based on a trisamide of trimesic acid
Authors: Varga József , Stoll Klaus , Menyhárd Alfréd , Horváth Zsuzsanna 
Published: March 2011

AbstractTris‐2,3‐dimethyl‐hexylamide of trimesic acid (TATA) is an new type of β‐nucleating agent for isotactic polypropylene (iPP). The crystallization, melting characteristics, and the supermolecular structure of iPP nucleated with TATA were studied on the samples crystallized under nonisothermal and isothermal conditions. The β‐nucleating ability of TATA was rather high even at low concentration. It was established that TATA possessed dual nucleating ability generating samples with mixed (α and β) polymorphic compositions. The β‐content showed an maximum value at low concentrations (10–100 ppm) of TATA. The β‐content decreased with increasing concentration of TATA in the higher concentration range. The highest β‐content (about 80%) was achieved at the crystallization temperature Tc = 110–120°C at low concentration of TATA. The crystallization curves registered at constant cooling rate or under isothermal condition have a single peak in spite of the formation of two polymorphic modifications. The crystallization isotherms cannot be linearized according to the Avrami equation because of simultaneous crystallization of the α‐and β‐forms, having different nucleation and growth rate. It was also found that the β‐content increased with increasing conversion during isothermal crystallization because of the higher growth rate of the β‐phase. The β‐phase formed in the presence of TATA consist of lamellar crystallites. In the early stage of the crystallization, hedritic structure is formed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and properties of water‐borne polyurethane with branched straight aliphatic chains
Authors: Liu Fang , Han Dong 
Published: March 2011

AbstractWater‐borne polyurethane with branched straight aliphatic chains (CWPU) was prepared and characterized by FTIR and TEM. The relationship between structure and water‐resistance of CWPU was studied. The results showed that the particle size of CWPU emulsion increases and the round particle turns into the spindle‐shaped particle with increasing of content of branched straight aliphatic chains. However, the particle size of CWPU emulsion is not sensitive to the increases of length of branched straight aliphatic chains. The water‐resistance and hydrophobic property of CWPU film increase with the increase of content and length of branched straight aliphatic chains. It is attributed to the hydrophobic layer of aliphatic chains enriched on the surface of CWPU film. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Physical properties and cure characteristics of natural rubber/nanoclay composites with two different compatibilizers
Authors: Doğan Mehmet , Oral Demet Dengiz , Yılmaz Betül , Savu Melih , Karahan Selçuk , Bayramlı Erdal 
Published: March 2011

AbstractThe effects of epoxidized natural rubber (ENR) and maleic anhydride‐grafted polybutadiene (PB‐g‐MA) as compatibilizers to rubber formulations with and without organo‐modified layered silicates are investigated. The physical properties and curing characteristics of composites are studied by moving die rheometer, rubber process analyzer, tensile, tear, and hardness testing. The state of organoclay intercalation was determined by X‐ray diffraction method. The addition of compatibilizers, especially ENR 50, results in further intercalation or exfoliation of the organoclay that increased the clay dispersion in the rubber matrix. ENR 50 with organo‐modified clay improves the physical properties and changes the curing profile. The addition of PB‐g‐MA without organoclay increases the tensile strength (σmax) by increasing the stock viscosity of the rubber compound. Interestingly, simultaneous increase in hardness and σmax is achieved in the presence of both compatibilizers, a characteristic that is difficult to achieve and sometimes required in rubber processing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Rheological behaviors and molecular weight distribution characteristics of bimodal high‐density polyethylene
Authors: Shen Hong‐Wang , Luan Tao , Xie Bang‐Hu , Yang Wei , Yang Ming‐Bo 
Published: March 2011

AbstractA series of bimodal high density polyethylene (PE) with different molecular weight distributions (MWDs) were prepared by melt blending, and the fitting multipeaks on Gaussian were used to analyze the MWD curves, and the ratio of the areas under unimodal curves was as a tool to characterize the MWD; the phase behaviors and rheological behaviors were studied by dynamic rheological. The results showed that homogeneous bimodal high density PEs could be successfully prepared via melt blending, and the bimodal characteristic could be adjusted as expected. For samples with the MWD peak positions unvaried, the storage modulus, complex viscosity, and zero‐shear viscosity decreased rapidly with the value of AL/U increasing. Especially in the low frequency region, the loss modulus surpassed the storage modulus (G″ > G′) when AL/U > 10.17 and the dynamic cross‐point Gx appeared and increased with increasing AL/U, with an increasing extent much larger than that due to the width of MWD. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Development of ultrafine chitosan fibers through modified wetspinning technique
Authors: Pati Falguni , Adhikari Basudam , Dhara Santanu 
Published: March 2011

AbstractChitosan has been extensively exploited in biomaterials research because of easy tailorable properties. Chitosan fibers are produced through either wetspinning or electrospinning. However, it is difficult to produce few microns fibers using either of these techniques. Present study focuses on production of ultrafine chitosan fibers through modified wetspinning technique by injecting homogenous chitosan solution through a very fine hole of silicone tube into either sodium tripolyphosphate (STPP) or sodium hydroxide (NaOH) bath by applying positive pressure. The gelation behavior of the chitosan was evaluated with STPP and NaOH solution through rheological study for comparative spinnability of chitosan in STPP and NaOH bath. Although gel strength of chitosan–NaOH system (240 Pa) was four times higher than that of chitosan–STPP system, gel breakdown rate was higher in previous case. From Fourier infrared spectroscopy (FTIR) analysis, ionic cross‐linking between TPP and chitosan molecules in chitosan–TPP fibers was confirmed. Scanning electron micrographs showed fine chitosan fibers with average diameter of ∼ 10 μm. These nonwoven fibers/scaffolds with interconnected porosity may find potential biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal properties and morphology of isotactic polypropylene/acrylonitrile–butadiene rubber blends in the presence and absence of a nanoclay
Authors: Razavi‐Nouri Mohammad , Naderi Ghasem , Parvin Ali , Ghoreishy Mir Hamid Reza 
Published: March 2011

AbstractA thermoplastic elastomer (TPE) nanocomposite based on polypropylene (PP), acrylonitrile–butadiene rubber (NBR), and a nanoclay (NC) was prepared in a laboratory mixer with a 54/40/6 weight ratio. The effects of NC on the thermal properties, crystalline structure, and phase morphology of the TPE nanocomposite were studied in this work. The results obtained from the nonisothermal crystallization of PP, PP/NBR, and PP/NBR/NC, which was carried out with differential scanning calorimetry, revealed that the overall rate of crystallization of PP decreased with the addition of NBR to PP and increased when NC was incorporated into the nanocomposite. In addition, the crystallite size distribution was more uniform for the PP phase crystallized in the nanocomposite versus the PP itself. Also, although the PP in the reference blend (PP/NBR) crystallized only in the α form, the crystalline structure of the PP incorporated into the nanocomposite was a mixture of α‐ and γ‐crystalline forms. The effects of NC on the phase morphology of PP/NBR blends prepared with three different cooling methods (quenching in liquid nitrogen, cooling between two metal plates at room temperature, and molding at a high temperature in a hot press) were studied. For the samples quenched in liquid nitrogen or cooled between metal plates, a particulate–cocontinuous morphology formed. However, for the samples prepared under a hot press, a laminar‐like morphology was observed. In all three cases, a similar particulate–cocontinuous morphology formed for the reference blend, but the rubber inclusions were always smaller than those of the TPE nanocomposite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Passivity‐based control for large‐signal stability of high‐order switching converters
Authors: Leyva R. , Olalla C. , Queinnec I. , Tarbouriech S. , Alonso C. , Martinez‐Salamero L. 
Published: March 2011

AbstractThis article presents a new passivity‐based control law that stabilizes the output voltage of a high‐order DC‐DC converter. Such nonlinear control law assures robust large‐signal stability, provides zero steady‐state error despite uncertainty in converter parameters and has enough degree of freedom to satisfy the usual transient specifications of DC‐DC converters. This new integral control is derived in three steps. First, a static law is obtained. Second, a positive semidefinite storage function is synthesized to guarantee zero steady‐state error of the output voltage. Finally, the storage functions of the first two steps are combined to derive the new control law for high‐order DC‐DC converters.Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Development of waxy cassava with different Biological and physico‐chemical characteristics of starches for industrial applications
Authors: Zhao Shan‐Shan , Dufour Dominique , Sánchez Teresa , Ceballos Hernan , Zhang Peng 
Published: March 2011

AbstractThe quality of cassava starch, an important trait in cassava breeding programs, determines its applications in various industries. For example, development of waxy (having a low level of amylose) cassava is in demand. Amylose is synthesized by granule‐bound starch synthase I (GBSSI) in plants, and therefore, down‐regulation ofGBSSIexpression in cassava might lead to reduced amylose content. We produced 63 transgenic cassava plant lines that express hair‐pin dsRNAs homologous to the cassavaGBSSIconserved region under the control of the vascular‐specific promoter p54/1.0 from cassava (p54/1.0::GBSSI‐RNAi) or cauliflower mosaic virus (CaMV) 35S (35S::GBSSI‐RNAi). After the screening storage roots and starch granules from field‐grown plants with iodine staining, the waxy phenotype was discovered: p54/1.0::GBSSI‐RNAi line A8 and 35S::GBSSI‐RNAi lines B9, B10, and B23. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis showed that there was no detectable GBSSI protein in the starch granules of plants with the waxy phenotype. Further, the amylose content of transgenic starches was significantly reduced (<5%) compared with the level in starch granules from the wild‐type (about 25%). The inner structure of the waxy starch granules differed from that of the untransformed ones, as revealed by transmission electron microscopy analysis as well as morphological changes in the iodine–starch complex. Endothermic enthalpy was reduced in waxy cassava starches, according to differential scanning calorimeter analysis. Except B9, all waxy starches displayed the A‐type X‐ray diffraction pattern. Amylogram patterns of the waxy cassava starches were analyzed using a rapid viscosity analyzer and found to have increased values for clarity, peak viscosity, gel breakdown, and swelling index. Setback, consistency, and solubility were notably reduced. Therefore, waxy cassava with novel starch in its storage roots was produced using the biotechnological approach, promoting its industrial utilization. Biotechnol. Bioeng. 2011; 108:1925–1935. © 2011 Wiley Periodicals, Inc.
Bioproduction of butanol in bioreactors: New insights from simultaneous in situ butanol recovery to eliminate product toxicity
Authors: Mariano Adriano Pinto , Qureshi Nasib , Filho Rubens Maciel , Ezeji Thaddeus Chukwuemeka 
Published: March 2011

AbstractSimultaneous acetone butanol ethanol (ABE) fermentation by Clostridium beijerinckii P260 and in situ product recovery was investigated using a vacuum process operated in two modes: continuous and intermittent. Integrated batch fermentations and ABE recovery were conducted at 37°C using a 14‐L bioreactor (7.0 L fermentation volume) containing initial substrate (glucose) concentration of 60 g/L. The bioreactor was connected in series with a condensation system and vacuum pump. Vacuum was applied continuously or intermittently with 1.5 h vacuum sessions separated by 4, 6, and 8 h intervals. A control ABE fermentation experiment was characterized by incomplete glucose utilization due to butanol toxicity to C. beijerinckii P260, while fermentation coupled with in situ recovery by both continuous and intermittent vacuum modes resulted in complete utilization of glucose, greater productivity, improved cell growth, and concentrated recovered ABE stream. These results demonstrate that vacuum technology can be applied to integrated ABE fermentation and recovery even though the boiling point of butanol is greater than that of water. Biotechnol. Bioeng. 2011; 108:1757–1765. © 2011 Wiley Periodicals, Inc.
An anatomic study using three‐dimensional reconstruction for pterygopalatine fossa infiltration via the greater palatine canal
Authors: Hwang Se Hwan , Seo Jae Hyun , Joo Young Hoon , Kim Byung Guk , Cho Jin Hee , Kang Jun Myung 
Published: March 2011

AbstractThe pterygopalatine fossa (PPF) is accessed via the greater palatine canal (GPC) in an attempt to reduce bleeding during paranasal sinus surgery. This study aims to investigate the anatomy of the greater palatine foramen (GPF), GPC, and the PPF, with reference to PPF infiltration using three‐dimensional reconstruction of computer tomographic (CT) scan measurements. The CT scans of 50 patients were retrospectively evaluated. The morphology of the GPF, GPC, and the PPF was assessed in a three‐dimensional model. The thickness of the mucosa over the GPF was evaluated in the parasagittal plane. The mean length of the GPC was 13.8 ± 2.0 mm, and the mean height of the PPF was 21.0 ± 3.4 mm. The mean angles of the GPC in relation to the hard palate and the PPF were 67.4° ± 6.9° and 159.8° ± 7.1°, respectively. The GPF was 16.2 ± 1.3 mm lateral to the sagittal plane of the posterior nasal spine (PNS) and 6.1 ± 1.7 mm anterior to the coronal plane of the PNS. The mean volume of the PPF was 1039.9 ± 280.0 mm3. The mean thickness of the mucosa overlying the GPF was 10.7 ± 1.8 mm. We recommend that the PNS may be used as the bony landmark to locate the position of the GPF during PPF infiltration. The needle delivering the anesthetic should be bent 25 mm from the tip at a 45° angle, and a 1‐ml injection of anesthetic should be administered in adults. Clin. Anat. 24:576–582, 2011. © 2011 Wiley‐Liss, Inc.
Accessory spleens at autopsy
Authors: Unver Dogan Nadire , Uysal Ismihan Ilknur , Demirci Serafettin , Dogan Kamil Hakan , Kolcu Giray 
Published: March 2011

AbstractAccessory spleens (AS) may be formed during embryonic development when some of the cells from the developing spleen are deposited along the path from the midline, where the spleen forms, over to its final location on the left side of the abdomen. An accessory spleen is usually near the spleen's hilum, but it may be embedded partly or wholly in the tail of the pancreas. The aim of this study was to investigate the incidence and distribution of AS during routine forensic autopsies. AS were investigated in 720 consecutive autopsy cases. Fifty‐four AS were found in 48 (6.7%) cases. AS were found in hilum of the main spleen in 28 cases, the great omentum in 13 cases, the pancreas in 5 cases, and the pelvis in 2 cases. There were two AS in two cases and three AS in another two cases. Awareness of the possible presence of AS is important because when splenectomy is performed for some conditions such as immune thrombocytopenic purpura, failure to remove the AS may result in the failure of the condition to resolve. Additionally, during medical imaging, AS may be confused for enlarged lymph nodes or neoplastic growths. In conclusion, autopsy series are useful for determining the incidences and the other features of AS in different populations, in addition to those studies using CT scans and those studies obtained during laparoscopic or open surgeries. Clin. Anat. 24:757–762, 2011. © 2011 Wiley‐Liss, Inc.