bluuebunny/crossref_metadata_2025 huggingface dataset:
La métamorphose progressive de l'agriculture tchèque
Authors: Simon Françoise , Blogowski Alain
Published: October 2009

Basé sur l'analyse de données macro et micro-économiques, l'article dresse un bilan de l'agriculture tchèque. En 1995, la production agricole, après une phase d'adaptation récessive, semble connaître une relance (différenciée selon les productions). Celle-ci, stimulée par le resserrement du ciseau des prix et l'octroi d'aides directes, ne permet toujours pas d'assurer aux exploitations -quelle que soit leur forme juridique ou leur situation géographique- un revenu suffisant pour renouveler le capital existant. Ceci a conduit le gouvernement à mettre en place une politique d'accompagnement vigoureuse qui vise en fait à favoriser la modernisation d'une agriculture compétitive dans les zones à faibles contraintes agronomiques, tout en soutenant le développement de systèmes extensifs dans les zones défavorisées. Appliquées à une agriculture où les grandes structures restent dominantes, les exploitations peu spécialisées et la main d'oeuvre importante, ces orientations ont des conséquences sur les formes d'aides que l'Union européenne peut apporter.
Dynamiques et compétitivités agro-alimentaires dans les peco
Authors: Pouliquen Alain
Published: October 2009

Agrofood dynamics and competitiveness in the ceecs : implications for the E.U. enlargement

In 1994, some prominent western assessments expressed no doubt on the actual and foreseeable agrofood competitiveness of the CEECS, compared to the EU. This lead to dramatize the risk of more excess supplies after enlargement, hence the need for radical further step of CAP reform. Carefully re-visiting and updating relevant evidence lead us to different views. For a core of basic products and Central European countries, the EU 15 would likely draw durable net trade advantage from mutual de-protection. Meanwhile, such a scenario requires : further cap reform for removing quantitative self-limitation to net trade expansion eastward, and significant pre- (and post) accession structural supports by the eu to the CEECS.
La pratique du prêt avec remise de gage. Instrument de financement en milieu rural au Cameroun
Authors: Foko Emmanuel
Published: October 2009

Les pratiques de crédit en milieu rural mettent en œuvre de nombreuses sources et pour des utilisations diverses. De nombreuses formes de garanties sont exigées. La mise en gage de biens est la forme de garantie matérielle la plus répandue. Une analyse de ce système de prêt avec mise en gage de bien à Bafou (village Bamiléke de l'Ouest Cameroun) a montré qu'il s'agit d'une pratique bien connue et assez répandue. L'examen de la nature des biens impliqués a fait ressortir la place prépondérante des parcelles de terrain, suivie des plantations de caféier. Dans l'ensemble, les biens productifs sont préférés en raison des possibilités d'usufruit qu'ils offrent. Les garanties sont rarement exécutées, compte tenu de nombreuses difficultés qui y sont associées. En cas de défaillance, le créancier conserve la propriété des biens en question ou se paie sur la récolte jusqu'à extinction de la dette. L'intérêt (ou mieux le gain) tiré de la transaction, bien que le plus souvent implicite, semble jouer un rôle important dans la décision d'accepter un bien en gage. La contribution de cette pratique au financement des activités rurales est cependant limitée.
Developmental patterns in anatomy are shared among separate evolutionary origins of stem succulent and storage root‐bearing growth habits in Adenia (Passifloraceae)
Authors: Hearn David J.
Published: October 2009

The architecture of flowering plants is astonishingly diverse. To understand evolutionary patterns and processes that account for this diversity, I investigated developmental anatomy of storage roots and stems of 58 species in the genus Adenia (Passifloraceae) using an explicit phylogenetic context. Because expanded storage roots and stem succulence evolved multiple times in Adenia, patterns of transition between succulent and nonsucculent forms were analyzed using a comparative test that accommodates phylogenetic uncertainty. I tested the innervation hypothesis, wherein I expected the evolution of vascular strands to be correlated with evolutionary increases in water storage tissue if evolution of vascular strands facilitates transport through water and starch storage structures. Not only is evolution of vascular strands in stems statistically coupled with evolutionary increases in parenchyma storage tissue, most lineages that evolved expanded storage roots also evolved vascular strands in these roots in parallel to succulent stems. I proposed that vascular strands and closely associated storage parenchyma found in both roots and shoots of Adenia comprise a homologous unit. A switch‐like evolutionary mechanism that alters the spatial expression of this unit between roots and shoots can account, in large part, for transitions between markedly different habits such as storage‐rooted herbs and succulent‐stemmed shrubs.
The diversity-validity dilemma: In search of minimum adverse impact and maximum utility.
Authors: Theron Callie
Published: October 2009

Selection from diverse groups of applicants poses the formidable challenge of developing valid selection procedures that simultaneously add value, do not discriminate unfairly and which minimise adverse impact. Valid selection procedures used in a fair, non-discriminatory manner that optimises utility, however, very often result in adverse impact against members of protected groups. More often than not, the assessment techniques used for selection are blamed for this. The conventional interpretation of adverse impact results in an erroneous diagnosis of the fundamental causes of the under-representation of protected group members and, consequently, in an inappropriate treatment of the problem.
Case report: Ocular malformation with a ′double globe′ appearance
Authors: Kim Usha R , Arora Vipul , Shah Akash D , Srinivasan KG
Published: October 2009

Colobomatous cyst of the orbit is a rare congenital cystic malformation associated with ocular maldevelopment. Usually, the cyst is associated with a microphthalmic globe. We present a rare case of a unilateral large colobomatous cyst associated with a normal-sized globe, giving the appearance of a double globe on imaging.
Case Report: Magnetic resonance imaging in rabies encephalitis
Authors: Rao Arekapudi Subramanyeswara , Varma Dandu Ravi , Chalapathi Rao Mamidi Venkata , Mohandas Surat
Published: October 2009

Rabies encephalitis is an invariably fatal disease characterized by typical clinical symptoms. Although the diagnosis of this condition can be made on the basis of the patient′s history and the classical clinical presentation, neuroimaging may still play a role, especially for establishing an early diagnosis in cases with atypical presentations or when the history of animal bite is not forthcoming. We report the MRI findings in a case of furious rabies encephalitis and describe the utility of diffusion imaging in its diagnosis.
Case Report: Intracranial peripheral primitive neuroectodermal tumor - Ewing′s sarcoma of dura with transcalvarial-subgaleal extension: An unusual radiological presentation
Authors: Bano Shahina , Yadav Sachchida Nand , Garga Umesh Chandra
Published: October 2009

The occurrence of the intracranial, peripheral, primitive, neuroectodermal tumor, Ewing′s sarcoma (pPNET-ES) of the dura, is very rare. Immunophenotypical as well as genetic analyses play key roles in its diagnosis and differentiation from central PNET. We describe here the CT scan and MRI findings of an interesting case of intracranial pPNET-ES arising from the anterior falx cerebri with a trancalvarial-subgaleal extension.
CRM as Institution - Imaginary, Legitimacy and Appropriation
Authors: Benavent Christophe
Published: October 2009

In this paper, we explore the idea that an IS could act as an institution in itself, if its legitimacy is well established, even the knowledge of the system is weak. This is in line with some theory of
appropriation, and against the cognitive approach of the reason action theory. But we explore also one condition to gain legitimacy, which is that the system and proposed usage fit to the imaginary of the adopting population. Imaginary plays also a role along the appropriation process acting as a kind of pre-knowledge.
The influence of violent and nonviolent computer games on implicit measures of aggressiveness
Authors: Bluemke Matthias , Friedrich Monika , Zumbach Joerg
Published: October 2009

We examined the causal relationship between playing violent video games and increases in aggressiveness by using implicit measures of aggressiveness, which have become important for accurately predicting impulsive behavioral tendencies. Ninety‐six adults were randomly assigned to play one of three versions of a computer game that differed only with regard to game content (violent, peaceful, or abstract game), or to work on a reading task. In the games the environmental context, mouse gestures, and physiological arousal—as indicated by heart rate and skin conductance—were kept constant. In the violent game soldiers had to be shot, in the peaceful game sunflowers had to be watered, and the abstract game simply required clicking colored triangles. Five minutes of play did not alter trait aggressiveness, yet an Implicit Association Test detected a change in implicit aggressive self‐concept. Playing a violent game produced a significant increase in implicit aggressive self‐concept relative to playing a peaceful game. The well‐controlled study closes a gap in the research on the causality of the link between violence exposure in computer games and aggressiveness with specific regard to implicit measures. We discuss the significance of importing recent social–cognitive theory into aggression research and stress the need for further development of aggression‐related implicit measures. Aggr. Behav. 36:1–13, 2010. © 2009 Wiley‐Liss, Inc.
Metastable Copper‐Phthalocyanine Single‐Crystal Nanowires and Their Use in Fabricating High‐Performance Field‐Effect Transistors
Authors: Xiao Kai , Li Rongjin , Tao Jing , Payzant Edward A. , Ivanov Ilia N. , Puretzky Alex A. , Hu Wenping , Geohegan David B.
Published: October 2009

This paper describes a simple, vapor‐phase route for the synthesis of metastable α‐phase copper‐phthalocyanine (CuPc) single‐crystal nanowires through control of the growth temperature. The influence of the growth temperature on the crystal structures, morphology, and size of the CuPc nanostructures is explored using X‐ray diffraction (XRD), optical absorption, and transmission electron microscopy (TEM). α‐CuPc nanowires are successfully incorporated as active semiconductors in field‐effect transistors (FETs). Single nanowire devices exhibit carrier mobilities and current on/off ratios as high as 0.4 cm2 V−1 s−1 and >104, respectively.
Delivery of Nucleic Acids through the Controlled Disassembly of Multifunctional Nanocomplexes
Authors: Elsabahy Mahmoud , Wazen Nada , Bayó‐Puxan Núria , Deleavey Glen , Servant Marc , Damha Masad J. , Leroux Jean‐Christophe
Published: October 2009

In this study, novel pH‐responsive polyion complex micelles (PICMs) were developed for the efficient delivery of nucleic acid drugs, such as antisense oligonucleotide (AON) and short interfering RNA (siRNA). The PICMs consisted of a poly(amidoamine) (PAMAM) dendrimer–nucleic acid core and a detachable poly(ethylene glycol)‐block‐poly(propyl methacrylate‐co‐methacrylic acid) (PEG‐b‐P(PrMA‐co‐MAA)) shell. The micelles displayed a mean hydrodynamic diameter ranging from 50 to 70 nm, a narrow size distribution, and a nearly neutral surface charge. They could be lyophilized without any additives and stored in dried form. Upon redispersion in water, no change in complexation efficiency or colloidal properties was observed. Entry of the micelles into cancers cells was mediated by a monoclonal antibody fragment positioned at the extremity of the PEG segment via a disulfide linkage. Upon cellular uptake and protonation of the MAA units in the acidic endosomal environment, the micelles lost their corona, thereby exposing their positively charged endosomolytic PAMAM/nucleic acid core. When these pH‐responsive targeted PICMs were loaded with AON or siRNAs that targeted the oncoprotein Bcl‐2, they exhibited a greater transfection activity than nontargeted PICMs or commercial PAMAM dendrimers. Moreover, their nonspecific cytotoxicity was lower than that of PAMAM. The pH‐responsive PICMs reported here appear as promising carriers for the delivery of nucleic acids.
Capsosomes with Multilayered Subcompartments: Assembly and Loading with Hydrophobic Cargo
Authors: Hosta‐Rigau Leticia , Städler Brigitte , Yan Yan , Nice Edouard Collins , Heath Joan K. , Albericio Fernando , Caruso Frank
Published: October 2009

Therapeutic artificial cells or organelles are nanoengineered vehicles that are expected to substitute for missing or lost cellular function. The creation of capsosomes, polymer carrier capsules containing liposomal subcompartments, is a promising approach towards constructing such therapeutic devices using the layer‐by‐layer assembly method. Herein, the assembly of intact, nonaggregated capsosomes containing multiple liposome layers is reported. It is also further demonstrated that thiocoraline, a hydrophobic model peptide with antitumor activity, can be efficiently loaded into the membrane of the liposomal subcompartments of the capsosomes. Cell viability assays verify the activity of the trapped antitumor cargo. It is also shown that pristine capsosomes do not display inherent cytotoxic effects. The ability to tune the number of liposome layers and hence the drug loading in capsosomes as well as their noncytotoxicity provide new opportunities for the creation of therapeutic artificial cells and organelles.
Analysis of a continuous rotary‐drum filtration system
Authors: Davis H. Ted , Caretta Raul A.
Published: October 2009

The equation traditionally used to analyze a rotary‐drum vacuum filtration system is strictly valid only for flat filters immersed during the filtration cycle. In this article we derive the equation appropriate for a rotary‐drum filter and find that the results of calculated areas differ by a factor 5 from the fully immersed filter result. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Quantitative analysis of alternative transcripts of human PCDH11X/Y genes
Authors: Ahn Kung , Huh Jae‐Won , Kim Dae‐Soo , Ha Hong‐Seok , Kim Yun‐Ji , Lee Ja‐Rang , Kim Heui‐Soo
Published: October 2009

The Protocadherin 11X/Y (PCDH11X/Y) gene pair has been proposed as a carrier of the variation relating to cerebral asymmetry and psychosis on the ground that the Y gene was generated by duplication at 6 million years (close to the chimpanzee–human separation) and there is a case for an X/Y determinant of cerebral asymmetry. The present article investigated the patterns of alternative splicing and expression of the PCDH11X/Y genes. Twelve alternative transcripts of PCDH11X/Y genes were presently identified by in silico analysis. To investigate the biological roles of alternative transcripts of PCDH11X/Y genes, the transcripts were analyzed by real‐time reverse transcription‐polymerase chain reaction amplification. A total of 31 normal tissues including 11 different regions of human brain were used to investigate a wide spectrum of expression profiles. Dominant expression patterns were identified in several tissues (Tx1‐fetal liver; Tx3‐adult brain; Tx4‐adult brain and kidney; Tx5‐bone marrow; Ty1‐fetal brain; Ty2‐adrenal gland). Tx4 transcripts showed specific expression patterns in olfactory tissues. The findings can guide functional investigation of neuropsychiatric disorders. © 2009 Wiley‐Liss, Inc.
Investigation of the electropolymerization of o‐toluidine and p‐phenylenediamine and their electrocopolymerization by in situ ultraviolet–visible spectroelectrochemistry
Authors: Zhang Guirong , Zhang Aijian , Liu Xiuli , Zhao Shufeng , Zhang Jingbo , Lu Jiaxing
Published: October 2009

Under the conditions of potentiostatic electrolysis, the electropolymerization of o‐toluidine (OT) and para‐phenylenediamine (PPDA) and the electrocopolymerization between OT and PPDA on an indium tin oxide (ITO) conductive glass electrode at potentials of 0.7, 0.8, and 0.9 V were studied in detail by in situ ultraviolet–visible (UV–vis) spectrometry in 0.5 mol/L sulfuric acid media. It was shown that both OT and PPDA could be electropolymerized on the ITO electrode, which depended on the applied electrolysis potential and the concentration of the monomer. Furthermore, in situ UV–vis spectra indicated that the electrocopolymerization between OT and PPDA could happen. The presence of PPDA not only promoted polymerization but also accelerated polymerization, which was attributed to the formation of an intermediate result from the coupling of PPDA and the toluidine monomer cation radical. PPDA could be incorporated into the copolymer to make the copolymer have a phenazine or phenazine‐like cyclic structure, which was proven by the reflectance Fourier transform infrared spectra of the polymer and copolymer. The scanning electron microscopy morphology images of the polymers obtained showed that, in addition to accelerating polymerization, PPDA also could change the method of nucleation for the polymer to make the copolymer possess a fibrous surface morphology. The diameter of the fibroid copolymer was about 100 nm, and the length of that reached about 1000 nm. In the article, a newer concerned mechanism of copolymerization was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of glycidyl methacrylate treatment of empty fruit bunch (EFB) on the properties of ultra‐violet radiation cured EFB‐unsaturated polyester composite
Authors: Rozman H. D. , Rozyanty A. R. , Tay G. S. , Kumar R. N.
Published: October 2009

In this study, biofiber composites cured by ultra‐violet, were produced using pulp made from empty fruit bunch (EFB) as the reinforcing agent and unsaturated polyester as the matrix. The conversion of EFB fibers into pulp was carried out using organosolv pulping process. The EFB pulp was then chemically treated with glycidyl methacrylate (GMA) to different percentage of weight percent gain and the composites were made with different percentages of pulp loading. Results showed that the Kappa number of EFB decreased as the NaOH concentration in organosolv pulping increased. Composites which were made from GMA‐treated EFB showed better mechanical properties (tensile, flexural, and impact strength) than those of the unmodified. Fourier transform infrared spectroscopy showed peaks that proved the occurrence of grafting between GMA and OH from EFB pulp. Scanning electron microscope analysis showed the evidence of the enhancement of the compatibility between EFB and matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Epoxy composites reinforced by different size silica nanoparticles
Authors: Ou Cheng‐Fang , Shiu Ming‐Chin
Published: October 2009

Three series of epoxy/SiO2 composites, containing 0.3–7 wt % nanosized SiO2 with different specific surface area, were prepared by solution blending. The resulting composites exhibit the higher glass transition temperature (Tg) than that of pure epoxy. The Tg of composite showed a maximum increment of 35.3°C by the addition of 7 wt % A300. The trade name of A300 is Aerosil 300. It is one of the fumed silica nanoparticles products of Degussa. The decomposition temperatures (Td) of composites were always higher than that of pure epoxy and showed a maximum increment of 20.8°C by the addition of 5 wt % A300. The light transmittance of composites was as a function of the SiO2 content and size. The water permeability of composites decreased with increasing SiO2 content and the 7 wt % A300 composite exhibits a maximum decrement percentage of 35.6%. The Tg, Td, storage modulus, and water‐vapor barrier property are as a function of the SiO2 content and size. These properties increased as the content of SiO2 increased. The finer SiO2 are more effective in increasing the Tg, Td, and water‐vapor barrier property. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
P‐V‐T measurements on PMMA : PbTiO3 polymer‐ceramic composites with tunable thermal expansion
Authors: Chandra Amreesh , Best A. , Meyer W. H. , Wegner G.
Published: October 2009

Results of Pressure‐Volume‐Temperature measurement on Poly(methyl methacrylate) : Lead Titanate, PMMA : PbTiO3, composite system in the pressure and temperature range 0–200 MPa and 300–473 K, respectively, are presented. The thermal expansion coefficient in PMMA : PbTiO3 composite is expected to be quite complex because the polymer has positive thermal expansion coefficient, whereas the filler has a negative thermal expansion coefficient. In this present article, the effect of pressure on the volumetric thermal expansion coefficient in PMMA : PbTiO3 composite system is presented. It is shown that thermal expansion coefficient of the polymer can be tailored by adding filler which has negative thermal expansion coefficient. Theoretically, a simple additive rule is formulated which can predict the variation of expansion coefficient in the PMMA : PbTiO3 composite system. The limitation of the additive rule is also discussed. It is also shown that the glass transition temperature depends on filler concentration and also has strong pressure dependence. The reasons for large pressure dependence are discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of chitosan bicomponent nanofibers filled with hydroxyapatite nanoparticles via electrospinning
Authors: Shen Kai , Hu Qiaoling , Chen Liang , Shen Jiacong
Published: October 2009

Chitosan (CS) bicomponent nanofibers with an average diameter controlled from 100 to 50 nm were successfully prepared by electrospinning of CS and poly(vinyl alcohol) (PVA) blend solution. Finer fibers and more efficient fiber formations were observed with increased PVA contents. On this contribution, a uniform and ultrafine nanofibrous CS bicomponent mats filled with hydroxyapatite (HA) nanoparticles were successfully electrospun in a well devised condition. An increase in the contents of HA nanoparticles caused the conductivity of the blend solution to increase from 1.06 mS/cm (0 wt % HA) to 2.27 mS/cm (0.5 wt % HA), 2.35 mS/cm (1.0 wt % HA), respectively, and the average diameter of the composite fibers to decrease from 59 ± 10 nm(0 wt % HA) to 49 ± 10 nm (0.5 wt % HA), 46 ± 10 nm (1.0 wt % HA), respectively. SEM images showed that some particles had filled in the nanofibers whereas the others had dispersed on the surface of fibers, and EDXA results indicated that both the nanoparticles filled in the nanofibers and those adhered to the fibers were HA particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Characterization of polypyrrole/azocalix[4]arene salts: Electrical properties and thermal stability
Authors: Uygun Aysegul , Yavuz Ayse Gul , Sen Songul , Deligoz Fatma , Karakus Ozlem Ozen , Deligoz Hasalettin
Published: October 2009

Polypyrrole (PPy) was doped with the azocalix[4]arene [(5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]25,26,27,28‐tetrahydroxycalix[4]arene)] host species. PPy/azocalix[4]arene salts were characterized by FTIR, TGA, SEM, X‐ray diffraction, and conductivity measurements. The properties of PPy were investigated in the presence of azocalix[4]arene host species. The conductivity of PPy increased in the presence of azocalix[4]arene. TGA results indicated that the PPy/azocalix[4]arene salts have higher thermal stability than PPy. It was observed from SEM analysis that the particle diameter of PPy decreased with increasing content of azocalix[4]arene. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication and characterization of PEO/PPC polymer electrolyte for lithium‐ion battery
Authors: Yu Xiao‐Yuan , Xiao Min , Wang Shuang‐Jin , Zhao Qi‐Qiang , Meng Yue‐Zhong
Published: October 2009

A new poly(propylene carbonate)/poly(ethylene oxide) (PEO/PPC) polymer electrolytes (PEs) have been developed by solution‐casting technique using biodegradable PPC and PEO. The morphology, structure, and thermal properties of the PEO/PPC polymer electrolytes were investigated by scanning electron microscopy, X‐ray diffraction, and differential scanning calorimetry methods. The ionic conductivity and the electrochemical stability window of the PEO/PPC polymer electrolytes were also measured. The results showed that the Tg and the crystallinity of PEO decrease, and consequently, the ionic conductivity increases because of the addition of amorphous PPC. The PEO/50%PPC/10%LiClO4 polymer electrolyte possesses good properties such as 6.83 × 10−5 S cm−1 of ionic conductivity at room temperature and 4.5 V of the electrochemical stability window. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Cell culture on PCL/PLGA blends
Authors: Lucchesi Carolina , Barbanti Samuel H. , Joazeiro Paulo P. , Duek Eliana A. R.
Published: October 2009

Bioresorbable polymers have been studied as support for cell culture in the tissue engineering area. Osteoblastic cells were cultivated on poly(ε‐caprolactone), poly(lactic acid‐co‐glycolic acid), and (70/30), (50/50), and (30/70) blends. Cytotoxicity and cell adhesion assays and scanning electronic microscopy studies were described. The cells presented significant growth on the blends, showing no cytotoxic response. Results indicated that these blends are promising as devices for bone tissue applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characteristics of polystyrene–clay nanocomposites via in situ intercalative polymerization in a direct current electric field
Authors: Qi Rongrong , Jin Xing , Huang Shuangwu
Published: October 2009

Polystyrene (PS)/montmorillonite nanocomposites were prepared by the free‐radical polymerization of styrene‐containing dispersed clay in a direct current electric field. The intercalation spacing in the nanocomposites, the dispersion, and the orientation of these composites were investigated. The nanocomposites had higher Tg and better thermal stability when compared with the virgin PS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Superficial modification in recycled PET by plasma etching for food packaging
Authors: Cruz S. A. , Zanin M. , Nascente P. A. P. , Bica de Moraes M. A.
Published: October 2009

An oxygen plasma treatment has been used to improve the adhesion of amorphous hydrogenated carbon (a‐C:H) films onto surfaces of recycled poly(ethylene terephthalate) (PET). Modifications produced by the oxygen plasma on the PET surface in chemical bonds and morphology were investigated by X‐ray photoelectron spectroscopy and atomic force microscopy, respectively. Contact angle measurements were used to study the changes in the surface wettability. Adhesion of the a‐C:H film onto the PET surface was investigated by the tape test method. It was observed that the improvement in film adhesion is in good correlation with the increase in surface roughness, due to plasma etching, and with the appearance of oxygen‐related functional groups at the surface. The results of this study indicate that a‐C:H‐coated recycled PET can be used in food packaging. The a‐C:H film could be used as a functional barrier to reduce or prevent migration of contaminants from the polymer to the package content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nano‐AlN functionalization by silane modification for the preparation of covalent‐integrated epoxy/poly(ether imide) nanocomposites
Authors: Duan Jingkuan , Kim Chonung , Jiang Pingkai , Wang Genlin
Published: October 2009

Aluminum nitride nanoparticle (nano‐AlN) organically modified with the silane‐containing epoxide groups (3‐glycidoxypropyltrimethoxy silane, GPTMS) was incorporated into a mixture of poly(ether imide) (PEI), and methyl hexahydrophthalic anhydride‐cured bisphenol A diglycidyl ether grafted by GPTMS was prepared for nanocomposite. Scanning electron microscopy, transmission electron microscopy, and atomic force microscopy were used to investigate the microscopic structures of nanocomposites. According to experimental results, it was shown that addition of nano‐AlN and PEI into the modified epoxy could lead to the improvement of the impact and bend strengths. When the concentrations of nano‐AlN and PEI were 20 and 10 pbw, respectively, the toughness/stiffness balance could be achieved. Dynamic mechanical analysis (DMA) results displayed that two glass transition temperatures (Tg) found in the nanocomposites were assigned to the modified epoxy phase and PEI phase, respectively. As nano‐AlN concentration increased, Tg value of epoxy phase had gradually increased, and the storage modulus of the nanocomposite at the ambient temperature displayed an increasing tendency. Additionally, thermal stability of the nanocomposite was apparently improved. The macroscopic properties of nanocomposites were found to be strongly dependent on their components, concentrations, dispersion, and resulted morphological structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crystallization, melting behavior, and wettability of poly(ε‐caprolactone) and poly(ε‐caprolactone)/ poly(N‐vinylpyrrolidone) blends
Authors: Xing Zhimin , Yang Guisheng
Published: October 2009

Both wettability and crystallizability control poly(ε‐caprolactone)'s (PCL) further applications as biomaterial. The wettability is an important property that is governed by both chemical composition and surface structure. In this study, we prepared the PCL/poly(N‐vinylpyrrolidone) (PVP) blends via successive in situ polymerization steps aiming for improving the wettability and decreasing crystallizability of PCL. The isothermal crystallization of PCL/PVP at different PVP concentrations was carried out. The equilibrium melting point (T), crystallization rate, and the melting behavior after isothermal crystallization were investigated using differential scanning calorimetry (DSC). The Avrami equation was used to fit the isothermal crystallization. The DSC results showed that PVP had restraining effect on the crystallizability of PCL, and the crystallization rate of PCL decreased clearly with the increase of PVP content in the blends. The X‐ray diffraction analysis (WAXD) results agreed with that. Water absorptivity and contact angle tests showed that the hydrophilic properties were improved with the increasing content of PVP in blends. The coefficient for the water diffusion into PCL/PVP blends showed to be non‐Fickian in character. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of transparent poly(methyl methacrylate)/Na+‐MMT nanocomposite films by solution casting
Authors: Wu Tongfei , Xie Tingxiu , Yang Guisheng
Published: October 2009

Films of poly(methyl methacrylate) (PMMA)/sodium montmorillonite (Na+‐MMT) nanocomposites have been successfully prepared utilizing Na+‐MMT by N,N‐dimethylformamide solution casting. The nanocomposite films show high transparency, enhanced thermal resistance, and mechanical properties in comparison with the neat polymer film. The transparency of the films was investigated by UV‐vis spectra. The exfoliated dispersion of Na+‐MMT platelets in nanocomposites were investigated by X‐ray diffraction and transmission electron microscopy. The enhanced thermal resistance and mechanical properties of PMMA were studied by thermal gravimetric analysis and dynamic mechanical analysis, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of the process parameters on the initial burst release of poly(lactide‐co‐glycolide) microspheres containing bovine serum albumin by the double‐emulsion solvent evaporation/extraction method
Authors: Wang Zheng
Published: October 2009

The effects of fabrication parameters on the morphology, drug loading, and initial burst release of poly(lactide‐co‐glycolide) microspheres loaded with bovine serum albumin were investigated to establish an optimal process and system for the in vivo delivery of therapeutic proteins. Through the addition of salts or sugars to induce an osmotic pressure in the external water phase, large microspheres were seen to have their morphology, drug loading, and initial burst release significantly affected. However, the effect was not observed for compact microspheres less than 10 μm in diameter. The presence of poly(vinyl alcohol), Pluronic F127, and Tween 80 in the internal water phase had detrimental effects on the drug loading because of the depressed stability of the primary emulsion and competitive interactions of surface‐active substances with the polymer. However, the simultaneous addition of salts to the external water phase resulted in enhanced drug loading and decreased initial burst. The polymer concentration and volume of the internal water phase were important factors influencing the characteristics of the microspheres. These parameters were optimized for achieving the maximal drug loading and a low initial burst. The solvent extraction method yielded microspheres with a higher drug loading and a lower initial burst in comparison with the solvent evaporation method. Different ranges of protein encapsulation efficiencies were obtained with blends of poly(lactide‐co‐glycolide) and poly(ethylene glycol), depending on the molecular weight and content of poly(ethylene glycol). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Strategies for the production of high solids acrylic/methacrylic core‐shell latices
Authors: Udagama R. , Mckenna T. F. L.
Published: October 2009

Well‐defined poly(butyl acrylate)/poly(methyl methacrylate) (PBA/PMMA) core shell particles with a moderately high solid content (49%) and particle diameters of less than 200 nm were prepared via seeded emulsion polymerization with a redox initiator and an anionic surfactant. Low‐viscosity (less than 150 cps at 20 s−1) latex products were obtained by controlling the particle size distribution to within certain limits. Polymerization conversion and kinetics were followed gravimetrically and were adjusted so as to obtain recipes that could be scaled‐up for industrial production. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the preparation of cellulose pellets on the dispersion of cellulose fibers into polypropylene matrix during extrusion
Authors: Le Baillif Marie , Echtermeyer Andreas
Published: October 2009

Cellulose fibers are rarely used for the extrusion of composites because of the problems in feeding them into the extruder and in dispersing them properly. Pelletization made it possible to feed cellulose fibers into extruder, but it reduced dramatically the fiber length. The goal of this study was to optimize the pelletization process for extrusion applications. Bleached sulfite cellulose fibers were pelletized at different moisture contents and with the optional addition of carboxymethyl cellulose (CMC). The pellets were subsequently extruded with polypropylene matrix without compatibilizer. Fiber dispersion and fiber breakage during extrusion were investigated. Pre‐blending of polymer and fiber pellets and introduction of the fibers through a side extruder were compared. CMC acted as a processing aid during pelletization, resulting in lower fiber breakage but in compact and stiff pellets. Lower moisture content also increased the compactness of the pellets. The dispersability of the fibers during extrusion decreased with increased pellets' compactness. CMC created inter‐fiber bonds, decreasing further the fibers' dispersability. The fiber length in the composites was the same regardless of the pelletization parameters. Early introduction of the fibers improved fiber dispersion. Feeding through side extruder was more stable and more reliable than pre‐blending. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A study on ligno‐cellulosic fabric Hardwikia binata
Authors: Prasad C. Venkata , Rao K. Chowdoji , Reddy G.Venkata , Kim Yong‐Ha , Rani T. Shobha , Subha M. C. S.
Published: October 2009

A naturally occurring fabric belonging to the species Hardwikia binata was extracted from the sheath of stem, bark, and branches of the tree. The fabric specimens were treated with sodium hydroxide and poly (vinyl alcohol). The morphology of the fabric specimens before and after NaOH treatment was studied using scanning electron microscopy technique. Ligno‐cellulosic properties of fabric were analyzed by XRD, FTIR, and thermo gravimetric methods before and after NaOH treatment. Tensile strength and percentage of elongation at break of the fabric were also studied by using a universal testing machine (model AGS‐10kNG). The results showed that the poly (vinyl alcohol)‐treated fabric specimens showed higher tensile strength than sodium hydroxide‐treated fabric specimens. The Binata fabric has good thermal resistance and was also found to increase by alkali treatment. The FTIR method indicates lowering the hemi cellulose and lignin content by alkali treatment in the fabric. Further, the X‐ray diffraction studies revealed an increase in crystallinity of the fabric by alkali treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and in vitro evaluation of new pH‐sensitive hydrogel beads for oral delivery of protein drugs
Authors: El‐Sherbiny I. M. , Abdel‐Bary E. M. , Harding D. R. K.
Published: October 2009

New biodegradable pH‐responsive hydrogel beads based on chemically modified chitosan and sodium alginate were prepared and characterized for the controlled release study of protein drugs in the small intestine. The ionotropic gelation reaction was carried out under mild aqueous conditions, which should be appropriate for the retention of the biological activity of an uploaded protein drug. The equilibrium swelling studies were carried out for the hydrogel beads at 37°C in simulated gastric (SGF) and simulated intestinal (SIF) fluids. Bovine serum albumin (BSA), a model for protein drugs was entrapped in the hydrogels and the in vitro drug release profiles were established at 37°C in SGF and SIF. The preliminary investigation of the hydrogel beads prepared in this study showed high entrapment efficiency (up to 97%) and promising release profiles of BSA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of copolymer from 1,3,5‐trioxane and 1,3‐dioxolane catalyzed by Maghnite‐H+
Authors: Beloufa Khadidja , Sahli Nabahat , Belbachir Mohamed
Published: October 2009

Copolymers (polyoxymethylene) were prepared by cationic copolymerization of 1,3,5‐trioxane (TOX) with 1,3‐dioxolane (DOX) in the presence of Maghnite‐H+ (Mag‐H+) in solution. Maghnite is a Montmorillonite sheet silicate clay, with exchanged protons to produce Mag‐H+. Various techniques, including 1H‐NMR, 13C‐NMR, FT‐IR spectroscopy, and Ubbelohde viscometer were used to elucidate structural characteristics properties of the resulting copolymers. The influence of the amount of catalyst, of dioxolane (DOX), temperature, solvent, and time of copolymerization on yield and on intrinsic viscosity of copolymers was studied. The yield of copolymerization depends on the amount of Mag‐H+ used and the reaction time. We also propose mechanisms involved in the synthesis of copolymer (polyoxymethylene). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A study on composites from phenol‐formaldehyde‐casein resin
Authors: Raval Dipak K. , Vyas Sachin K. , Parmar Jitendra K.
Published: October 2009

A modified phenol‐formaldehyde (PF) resin was synthesized under alkaline condition in varying proportion of casein up to 20% (w/w) of phenol. All the prepared resins were characterized by free phenol content, free formaldehyde content, viscosity measurements, number average molecular weight determination by conductometry and Infrared Spectroscopy (IR). Their curing kinetics was studied isothermally and by differential scanning calorimetry (DSC) on dynamic runs. The resin samples were cured using concentrated hydrochloric acid and hexamine individually. Cured resins were characterized by IR and Thermogravimetry (TGA). Glass fabric reinforced composites (GFRC) were fabricated by maintaining 40 : 60 proportion of resin to reinforcement material. The laminates thus formed were characterized for their mechanical properties and chemical resistance. Enhancements in thermal stability of the resin as well as toughness of composite with increase in casein content were observed for the resins studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Water resistance, mechanical properties, and biodegradability of poly(3‐hydroxybutyrate)/starch composites
Authors: Ismail A. M. , Gamal M. A. B.
Published: October 2009

Composites of poly(3‐hydroxybutyrate), P(3HB), and starch were prepared by solution casting technique. To improve adhesion of starch to P(3HB), stearic acid was added as a compatibilizer and glycerol as a plasticizer. The water resistance, mechanical, and biodegradable properties of the P(3HB)/starch composites were studied. Diffusion and penetration coefficients of water increased with increasing starch content in the composites. The results showed that the elastic modulus and strain at rupture of the P(3HB)/starch composites were enhanced by increasing starch content upto 10 wt % and the tensile strength increased from 21.2 to 93.9 MPa. The presence of starch content higher than 10 wt % had an adverse effect on the mechanical properties of the investigated composites. The biodegradation rate using Actinomycetes increased proportionally to the starch content in the composite and accelerated in a culture medium of pH ≈ 7.0 at 30°C. Enzymatic degradation experiments showed that lipase produced by Streptomyces albidoflavus didnot degrade P(3HB)/starch composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Metal coordination and selectivity with oxine ligands bound to silica polyamine composites
Authors: Wong Yuen Onn , Miranda Paul , Rosenberg Edward
Published: October 2009

A series of oxine ligands, 5‐X, 8OHC9H6N (X = H, Cl, SO3H) have been covalently bound to a silica gel polyamine composite made from a silanized amorphous silica xerogel and poly(allylamine) (BP‐1) by the Mannich reaction. The resulting modified composites WP‐4(X = H), CB‐1(X = Cl), and SB‐1(X = SO3H) were characterized by elemental analysis, FTIR, and solid state CPMAS‐13C‐NMR. Using the analytical data before and after the ligand modification, the ligand loading could be estimated and in combination with metal ion capacities a metal to ligand ratio could be obtained. The composites WP‐4 and CB‐1 both showed ratios of approximately 1 : 1 while the sulfonate modified composite, SB‐1, showed a metal to ligand ratio of 1 : 2. This is tentatively interpreted in terms of a zwitterionic oxine as the dominant species at pH = 2 where the sulfonic acid group is ionized, the quinoline nitrogen is protonated and where two sulfonate groups on adjacent oxines bind a trivalent or divalent ion. All the modified composites show a clear selectivity for trivalent over divalent ions and a good selectivity for gallium over aluminum. The substituent groups on the oxine ligand have only a minor influence on these selectivity trends but SB‐1 shows slightly better capture kinetics. The selectivity for gallium over aluminum is applied to the separation of gallium from aluminum, ferrous, and zinc in an acid ore leach of solid tailings obtained from a zinc mine using WP‐4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of atactic poly(vinyl alcohol)/silver composite nanofibers by electrospinning and their characterization
Authors: Lee Young Jae , Lyoo Won Seok
Published: October 2009

Poly(vinyl alcohol) (PVA)/silver composite nanofibers were successfully prepared by the electrospinning method. Water‐based colloidal silver in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic–inorganic composite nanofibers. The ratio of silver colloidal solution to PVA played an important role in the formation of the PVA/silver composite nanofibers. We prepared two different atactic PVA/silver nanocomposites with number‐average degrees of polymerization of 1700 and 4000 through electrospinning with various processing parameters, such as initial polymer concentration, amount of silver colloidal solution, applied voltage, and tip‐to‐collector distance. The PVA/silver composite nanofibers were characterized by field emission scanning electron microscopy and transmission electron microscopy (TEM). TEM images showed that silver nanoparticles with an average diameter of 30–50 nm were obtained and were well distributed in the PVA nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of a polymer/multiwalled carbon nanotube composite and its application in the hydration of ethylene oxide
Authors: Yu Fengping , Cai Hong , He Wenjun , Yang Weimin , Xie Zaiku
Published: October 2009

Multiwalled carbon nanotubes (MWNTs) were incorporated into the crosslinking network of a styrene–divinylbenzene copolymer (PS–DVB) via suspension polymerization. The prepared crosslinking PS–DVB with MWNTs was first treated with chloromethyl methyl ether to introduce chloromethyl groups through Friedel–Craft reaction; then, the chloromethylation product was reacted with trimethyl amine to obtain the target polymer/carbon nanotube composite: PS–DVB/MWNT ion‐exchange resin. The obtained composite was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, and X‐ray photoelectron spectroscopy. The results show the successful incorporation of MWNTs into the polymer network. The physical and chemical properties of the PS–DVB/MWNT ion‐exchange resin were nearly the same as those of the controlled sample. With its excellent antiswelling properties, the catalytic behavior of the polymer composite was examined in the hydration of ethylene oxide. Also, it demonstrated excellent stability as a catalyst without a decline in conversion and selectivity in a long‐time run. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Using hydroxypropyl‐β‐cyclodextrin for the preparation of hydrophobic poly(ketoethyl methacrylate) in aqueous medium
Authors: Ding Lei , He Qinxiong , Deng Jianping
Published: October 2009

This work was committed to the polymerization of hydrophobic ketoethyl methacrylate monomer in aqueous medium in the presence of cyclodextrin, instead of polymerizing the monomer in toxic and volatile organic solvents. For this purpose, a new ketoethyl methacrylate monomer, p‐methylphenacylmethacrylate (MPMA), was synthesized from the reaction of p‐methylphenacylbromide with sodium methacrylate in the presence of triethylbenzylammonium chloride. The monomer was identified with FTIR, 1H and 13C‐NMR spectroscopies. Hydroxypropyl‐β‐cyclodextrin (HPCD) was used to form a water‐soluble host/guest inclusion complex (MPMA/HPCD) with the hydrophobic monomer. The complex was identified with FTIR and NMR techniques and polymerized in aqueous medium using potassium persulfate as initiator. During polymerization the resulting hydrophobic methacrylate polymer precipitated out with a majority of HPCD left in solution and a minority of HPCD bonded on the resulting polymer. The thus‐prepared polymer exhibited little difference from the counterparts obtained in organic solvent in number average molecular weight (Mn), polydispersity (Mw/Mn) and yield. The investigation provides a novel strategy for preparing hydrophobic ketoethyl methacrylate polymer in aqueous medium by using a monomer/HPCD inclusion complex. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Dependence of properties of expandable polystyrene particle foam on degree of fusion
Authors: Schellenberg Jürgen , Wallis Mario
Published: October 2009

Expandable polystyrene (EPS) particle foams were prepared in three major steps to investigate their mechanical, thermal, and fire behavior on their degree of fusion. Bending strength was found to increase progressively, whereas compressive stress was found to increase linearly with the degree of fusion of EPS particle foams. Although at low degree of fusion the flame heights, B2 was found to decrease, it remained constant at high degree of fusion. Optical microscopic method appeared to be more reliable than pneumatic method in the determination of degree of fusion over the whole range of EPS particle foams investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010