bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface modification of low‐density polyethylene films by a novel solution base chemical process
Authors: Bandopadhay D. , Tarafdar A. , Panda A.B. , Pramanik P. 
Published: March 2004

AbstractThe surfaces of the film samples of low‐density polyethylene (LDPE) were chemically modified with an aqueous solution of ammonium persulphate solution (0.1 M) and Fe (NO3)3,9H2O (0.2 M) heated to about 80°C for 2.5 h for which polar groups like OH, 〉CO, COOH, etc., were generated on the surface of the LDPE films. The modified films were analyzed by Infrared (IR) spectroscopy, Scanning Electron Microscopy (SEM), and Electron Spectroscopy for Chemical Analysis (ESCA). New surface of LDPE produced by this modification, demonstrated reasonable oxygen incorporation on the surface of polymer films through chemical bonding, which is essential for adhesion processes. For these chemical changes the extent of printability and adhesion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3046–3051, 2004
Determination of dissociable groups in natural and regenerated cellulose fibers by different titration methods
Authors: Fras Lidija , Laine Janne , Stenius Per , Stana‐Kleinschek Karin , Ribitsch Volker , Doleček Valter 
Published: March 2004

AbstractDifferent titration methods were applied with the purpose to determine the dissociation properties of a natural (cotton) and regenerated (viscose, modal and lyocell) cellulose fibers. Potentiometric and conductometric titration were used to determine the content of acidic groups. pK values were determined by potentiometric titration. Polyelectrolyte adsorption was used for surface and total charge determination, and to obtain information about charge location and accessibility of charged groups. It was found that the average content of acidic groups is higher in cotton fibers than in regenerated fibers. The fiber charge of cotton is due to the dissociation of two type of acidic groups, one with pK ≈3.5 and the other with pK ≈5.5. In regenerated fibers there is only one type of acidic groups (pK ≈3.5). The pK value of the stronger acid is typical for carboxyl group in uronic acids. The polyelectrolyte adsorption indicates that most of the carboxyl groups are located in an inner region of all cellulose samples (cotton and regenerated fibers). It is concluded that titration methods are powerful tools for monitoring the content, strength, and distribution of acidic groups, as well as the total charge of natural and regenerated cellulose fibers. The three methods give similar results on all analyzed samples and show good repeatability. The results of investigation make it quite clear that combination of all titrations yields relevant information about content and strength of acidic groups in both natural and regenerated cellulose fibers used in the manufacture of textiles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3186–3195, 2004
Colorants based on renewable resources and food‐grade colorants for application in thermoplastics
Authors: Van Den Oever M.J.A. , Boeriu C.G. , Blaauw R. , Van Haveren J. 
Published: March 2004

AbstractA series of colorants based on renewable resources and food‐grade colorants have been evaluated for use in polypropylene (PP) and polyvinylchloride (PVC). It has been found that most of these colorants can be processed in PP at 200°C or even 260°C while maintaining good color intensity and color brightness. The colorants evaluated cover a large part of the color spectrum. In PP, the light stability of alizarin (red), carmine (red), indigo (blue), purpurin (red), quinizarin (red), and the aluminium lakes of quinoline yellow (yellow) and indigo carmine (blue) is close to the requirements for indoor applications. The blue colorants indigo and the aluminium lake of indigo carmine are, in principle, sufficiently light stable in PP for indoor applications. A few colorants showed bleeding from PP. Bonding of migrating colorants to the reactive carrier maleic anhydride grafted polypropylene, however, reduced bleeding of the colorant to a large extent. Also after processing in PVC at 200°C, good color intensity and saturation is maintained. Quinizarin, a structural analog of alizarin and purpurin, shows a light stability performance that is close to commercial lead chromate/molybdate orange based colorants. The best performing natural colorants are sufficiently heat and light stable for applications where moderate properties concerning heat resistance and (UV) light stability are required, such as underground PVC water drainage pipes and indoor PP applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2961‐2969, 2004
Modeling PVTX diagrams: Application to various blends based on unsaturated polyester—Influence of thermoplastic additive, fillers, and reinforcements
Authors: Boyard N. , Vayer M. , Sinturel C. , Erre R. , Delaunay D. 
Published: March 2004

AbstractThe model previously proposed to predict the volume change of filled blends was extended to unsaturated polyester/styrene blends without or with thermoplastic additive and to blends with fillers and/or fibers. This model was based on experimental results from Pressure Volume Temperature X (PVTX) setup where temperature, conversion degree, and volume at a controlled pressure were monitored simultaneously. Predictions obtained from the model were compared to experimental results and were in good agreement. This model took into account thermal expansion, polymerization shrinkage, and shrinkage compensation via porosity formation. These phenomena were deconvoluted from the experimental curve and separately quantified. It was shown that shrinkage and its compensation induced a volume variation exhibiting a linear dependence with conversion degree. The influences of low‐profile additive content, pressure, fillers, and fiber presence on shrinkage control were highlighted. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2976–2988, 2004
Study on hot air aging and thermooxidative degradation of peroxide prevulcanized natural rubber latex film
Authors: Zhang Bei‐Long , Chen Mei , Ao Ning‐Jian , Deng Wei‐Yong , Liu Hui‐Lun 
Published: March 2004

AbstractThe air‐aging process at 120°C and the thermooxidative degradation of peroxide prevulcanized natural rubber latex (PPVL) film were studied with FTIR and thermal gravity (TG) and differential thermal gravity (DTG) analysis, respectively. The result of FTIR shows that the OH and COOH absorption of the rubber molecules at IR spectrum 3600–3200 cm−1, the CO absorption at 1708 cm−1, and the COH absorption of alcohol at 1105 and 1060 cm−1 increased continuously with extension of the aging time, but the CH3 absorption of saturated hydrocarbon at 2966 and 2868 cm−1, the CH3 absorption at 1447 and 1378 cm−1, and the CC absorption at 835 cm−1 decreased gradually. The result of TG‐DTG shows that the thermal degradation reaction of PPVL film in air atmosphere is a two‐stage reaction. The reaction order (n) of the first stage of thermooxidation reaction is 1.5; the activation energy of reaction (E) increases linearly with the increment of the heating rate, and the apparent activation energy (E0) is 191.6 kJ mol−1. The temperature at 5% weight loss (T0.05), the temperature at maximum rate of weight loss (Tp), and the temperature at final weight loss (Tf) in the first stage of degradation reaction move toward the high temperature side as the heating rate quickened. The weight loss rate increases significantly with increment of heating rate; the correlation between the weight loss rate (αp) of DTG peak and the heating rate is not obvious. The weight loss rate in the first stage (αf1) rises as the heating rate increases. The final weight loss rate in second stage (αf2) has no reference to heating rate; the weight loss rate of the rubber film is 99.9% at that time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3196–3200, 2004
Modification of adhesive properties of a polyethylene film by photografting
Authors: El Kholdi O. , Lecamp L. , Lebaudy P. , Bunel C. , Alexandre S. 
Published: March 2004

AbstractGraft polymerization of acrylic acid from monomer solutions in water or in bulk onto low‐density polyethylene film substrate was carried out by the method of continuous process under UV radiation. Effects of the nature of photoinitiator on acrylic acid grafting was first studied. One PI2 and two PI1 photoinitiators were used. Benzophenone was then retained for the following study. The influence of photoinitiator and monomer concentration was investigated by determining polymerization kinetics and grafted polymer amount. A study of surface wetting and morphological structure was then carried out on a bulk system and as a function of the photoinitiator concentration. Finally, such surface modification was studied with respect to its effect on the adhesion of an acrylic stick on its surface. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2803–2811, 2004
High‐performance epoxy hybrid nanocomposites containing organophilic layered silicates and compatibilized liquid rubber
Authors: Fröhlich J. , Thomann R. , Gryshchuk O. , Karger‐Kocsis J. , Mülhaupt R. 
Published: March 2004

AbstractA mixture of two epoxy resins, tetraglycidyl 4,4′‐diaminodiphenyl methane and bisphenol‐A diglycidylether, cured with 4,4′‐diaminodiphenyl sulfone, was used as matrix material for high‐performance epoxy hybrid nanocomposites containing organophilicly modified synthetic fluorohectorite and compatibilized liquid six‐arm star poly(propylene oxide‐block‐ethylene oxide) (abbreviated as PPO). The hydroxy end groups of the poly(propylene oxide‐block‐ethylene oxide) were modified, yielding a six‐arm star PPO with an average of two pendant stearate chains, two phenol groups, and two hydroxy end groups. The alkyl chains of the stearate end groups played an important role in tailoring the polarity of the polymer. Its phenol end groups ensured covalent bonding between liquid polymer and epoxy resin. Two different organophilic fluorohectorites were used in combination with the functionalized PPO. The morphology of the materials was examined by transmission electron microscopy. The hybrid nanocomposites were composed of intercalated clay particles as well as separated PPO spheres in the epoxy matrix. As determined by dynamic mechanical analysis, the prepared composites possessed glass‐transition temperatures around 220°C. Although the tensile moduli remain unaltered, the tensile strengths of the hybrid materials were significantly improved. The relatively high fracture toughness of the neat resin, though, was not preserved for the hybrid resins. Scanning electron microscopy of the fracture surfaces revealed extensive matrix shear yielding for the neat resin, whereas the predominant fracture mode of the hybrid nanocomposites was crack bifurcation and branching. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3088–3096, 2004
Mechanical properties, morphological structure, and thermal behavior of dynamically photocrosslinked PP/EPDM blends
Authors: Tang Longxiang , Qu Baojun , Shen Xiaofeng 
Published: March 2004

AbstractA dynamically photocrosslinked polypropylene (PP)/ethylene–propylene–diene (EPDM) rubber thermoplastic elastomer was prepared by simultaneously exposing the elastomer to UV light while melt‐mixing in the presence of a photoinitiator as well as a crosslinking agent. The effects of dynamic photocrosslinking and blend composition on the mechanical properties, morphological structure, and thermal behavior of PP/EPDM blends were investigated. The results showed that after photocrosslinking, tensile strength, modulus of elasticity, and elongation at break were improved greatly. Moreover, the notched Izod impact strength was obviously enhanced compared with corresponding uncrosslinked blend. Scanning electron microscopy (SEM) morphological analysis showed that for uncrosslinked PP/EPDM blends, the cavitation of EPDM particles was the main toughening mechanism; whereas for dynamically photocrosslinked blends, shear yielding of matrix became the main energy absorption mechanism. The DSC curves showed that for each dynamically photocrosslinked PP/EPDM blend, there was a new smaller melting peak at about 152°C together with a main melting peak at about 166°C. Dynamic mechanical thermal analysis (DMTA) indicated that the compatibility between EPDM and PP was improved by dynamic photocrosslinking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3371–3380, 2004
Rheological and thermal properties of thermoplastic natural rubbers based on poly(methyl methacrylate)/epoxidized‐natural‐rubber blends
Authors: Nakason C. , Panklieng Y. , Kaesaman A. 
Published: March 2004

AbstractEpoxidized natural rubbers (ENRs) with epoxide levels of 10, 20, 30, 40, and 50 mol % were prepared. The ENRs were later blended with poly(methyl methacrylate) (PMMA) with various blend formulations. The mixing torque of the blends was observed. The torque increased as the PMMA contents and epoxide molar percentage increased in the ENR molecules. Furthermore, the shear stress and shear viscosity of the polymer blends in the molten state increased as the ENR content and epoxide molar percentage increased in the ENR molecules. Chemical interactions between polar groups in the ENR and PMMA molecules might be the reason for the increases in the torque, shear stress, and viscosity. All the ENR/PMMA blends exhibited shear‐thinning behavior. This was observed as a decrease in the shear viscosity with an increase in the shear rate. The power‐law index of the blends decreased as the ENR contents and epoxide molar percentage increased in the ENR molecules. However, the consistency index (or zero shear viscosity) increased as the ENR contents and epoxide molar percentage increased. A two‐phase morphology was observed with scanning electron microscopy. The small domains of the minor components were dispersed in the major phase. For the determination of blend compatibility, two distinct glass‐transition‐temperature (Tg) peaks from the tan δ/temperature curves were found. Shifts in Tg to a higher temperature for the elastomeric phase and to a lower temperature for the PMMA phase were observed. Therefore, the ENR/PMMA blends could be described as partly miscible blends. According to the thermogravimetry results, the decomposition temperatures of the blends increased as the levels of ENR and the epoxide molar percentage increased. The chemical interactions between the different phases of the blends could be the reason for the increase. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3561–3572, 2004
Preparation, morphology, and mechanical properties of elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/polystyrene blends
Authors: Dong Jian , Liu Zonglin , Han Nianfeng , Wang Qin , Xia Yiran 
Published: March 2004

Abstractα,ω‐Dihydroxy‐polydimethylsiloxane/polystyrene (PDMS/PS) blends were prepared by the solution polymerization of styrene (St) in the presence of α,ω ‐dihydroxy‐polydimethylsiloxane (PDMS), using toluene as solvent and benzoyl peroxide (BPO) as initiator. The PDMS/PS blends obtained by this method are a series of stable, white gums, which were vulcanized to elastomers at room temperature with methyl‐triethoxysilicane (MTES). The use level of MTES was far more than the necessary amount used to end‐link hydroxy‐terminated chains of PDMS, with the excess being hydrolyzed to crosslinked networks, which were similar to SiO2 and acted as filler. Investigations were carried out on the elastomeric materials by extraction measurement, swelling measurement, and scanning electron microscopy. The extraction data show that at each composition the amount of soluble fraction is less than expected and the difference between experimental and theoretical values becomes more and more significant as PS content increases. This is mainly due to the grafting of PS onto PDMS and the entanglement of PS in the interpenetrating polymer network (IPN), which consists of either directly linked PDMS chains or chains linked via PS grafts and is formed by free radical crosslinking of PDMS during the radical polymerization of St. PS grafted on PDMS is insoluble and PS entangled in the IPN is difficult to extract. Both render the soluble fraction to be less than expected. As the St content in preparing PDMS/PS blends increases, the probability of grafting PS onto PDMS also increases, which may subsequently produce a higher crosslinking level of PDMS networks that linked via PS grafts by radical crosslinking. As a result, not only the amount of insoluble PS increases but also PS entangled in the IPN is more difficult to extract. Scanning electron microscopy demonstrates that the elastomer system has a microphase‐separated structure and a certain amount of PS remains in the PDMS networks after extraction, which is in accordance with the extraction data. Moreover, the mechanical properties of the elastormeric materials have been studied in detail. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3542–3548, 2004
Synthesis and Morphine Enhancement Activity of N‐[5‐(2‐phenoxyphenyl)‐1, 3, 4‐oxadiazole‐2‐yl]‐N′‐phenylurea Derivatives
Authors: Rad Ali Almasi , Sheikhha Majid , Hosseini Rohollah , Tabatabaic Sayyed Abbas , Shafiee Abbas 
Published: March 2004

AbstractThe synthesis of N‐[5‐(2‐phenoxyphenyl)‐1, 3, 4‐oxadiazole‐2‐yl]‐N′‐phenylurea derivatives is reported. The structures of these compounds are supported by their IR, 1H‐NMR and mass spectra. Conformational analysis and superimposition of energy minima conformers of these compounds on L‐365, 260, a known 3‐ureido‐1, 4‐benzodiazepine CCK‐B antagonist, showed that the aromatic rings fell in the same contour. Morphine analgesia enhancement evaluation of the synthesized compounds in comparison with a control group showed that compounds 8a, 8c, 8h—8j, 8l, 8o have significant effects.
Antioxidant Properties of Novel Benzimidazole Retinoids
Authors: Ates‐Alagoz Zeynep , Can‐Eke Benay , Coban Tulay , Iscan Mumtaz , Buyukbingol Erdem 
Published: March 2004

AbstractOur approach was to examine the antioxidant activity of novel retinoid derivatives containing the benzimidazole moiety. Their in vitro effects on rat liver microasomal, NADPH‐dependent lipid peroxidation levels and superoxide anion formation were determined. Lipid peroxidation in rat liver microsomes was reduced by some of the compounds in a dose‐dependent manner.
Non‐Thiol Farnesyltransferase Inhibitors: Utilization of the Near Aryl Binding Site by 5‐Arylacetylaminobenzophenones
Authors: Mitsch Andreas , Böhm Markus , Sattler Isabel , Schlitzer Martin 
Published: March 2004

AbstractWe recently described two novel aryl binding sites of farnesyltransferase. The arylacetyl residue was designed as an appropriate substituent for our benzo‐phenone‐based AAX‐peptidomimetic compound capable of occupying the near aryl binding site which is located next to the catalytic zinc ion. Non‐thiol farnesyl‐transferase inhibitors with micromolar to submicromolar activity were obtained.
Evolution, continuity, and disappearance of documents on a specific topic on the Web: A longitudinal study of “informetrics”
Authors: Bar‐Ilan Judit , Peritz Bluma C. 
Published: March 2004

AbstractThe present paper analyzes the changes that occurred to a set of Web pages related to “informetrics” over a period of 5 years between June 1998 and June 2003. Four times during this time span, in 1998, 1999, 2002, and 2003, we monitored previously located pages and searched for new ones related to the topic. Thus, we were able to study the growth of the topic, while analyzing the rates of change and disappearance. The results indicate that modification, disappearance, and resurfacing cannot be ignored when studying the structure and development of the Web.
Phenotypic expression of a family with multiple endocrine neoplasia type 2A due to a RET mutation at codon 618
Authors: Lindskog S , Nilsson O , Jansson S , Nilsson B , Illerskog A-C , Ysander L , Ahlman H , Tisell L-E 
Published: March 2004

Abstract

Background
Multiple endocrine neoplasia type 2A (MEN2A) is caused by missense mutations in the RET proto-oncogene on chromosome 10. This paper reports the phenotypic expression of a family with MEN2A, in which serine substitutes for cysteine at codon 618 in exon 10 of the RET gene. It was first claimed that medullary thyroid cancer (MTC) with this rare mutation led to mild disease; this has recently been updated to intermediate–high risk, based on stratified genetic information.

Methods
The family was mapped over six generations. In 1971 family members were invited to join a screening programme. Genetic testing was started in 1994.

Results
Twenty-two individuals with MTC were identified, 16 by the screening programme. One screened patient had a phaeochromocytoma and four had hyperparathyroidism. At surgery for MTC 12 patients had local tumour metastases and two young patients also had liver metastases. No screened patient died from MTC during a mean observation time of 19 years. Six other family members were diagnosed with MTC by signs and symptoms, five of whom died from MTC.

Conclusion
Because of the great interindividual differences in tumour aggressiveness within the family it is impossible to predict whether an individual gene carrier will have an aggressive MTC or not. This unpredictability is an additional argument, besides those obtained in stratified genetic studies, for operating on gene carriers at young age.
Late coronary stent thrombosis associated with exercise testing
Authors: Parodi Guido , Antoniucci David 
Published: March 2004

AbstractWe report a case of coronary stent thrombosis that occurred 6 months after the primary stenting of the left anterior descending coronary artery for acute myocardial infarction in a 75‐year‐old man. The reinfarction occurred the day after the demonstration of persistent optimal result of the percutaneous coronary intervention and immediately after exercise testing. A combined approach of a mechanical thrombus burden reduction by using AngioJet thrombectomy with adjunctive glycoprotein IIb/IIIa antagonist was performed, resulting in the complete removal of filling defects on the angiography. Catheter Cardiovasc Interv 2004;61:515–517. © 2004 Wiley‐Liss, Inc.
Sedimentation and Coalescence Profiles in Liquid‐Liquid Batch Settling Experiments
Authors: Yu G.‐Z. , Mao Z.‐S. 
Published: March 2004

AbstractA simple mathematical method for predicting the phase separation profiles of a batch liquid‐liquid dispersion is developed based on the empirical description of drops resting at a liquid‐liquid plane interface. The inflexion time, at which the sedimentation zone vanishes, can be obtained by analysis of the coalescence profile. Therefore, the sedimentation profile can be predicted and the size of drop and interfacial area can be estimated. The experiments were carried out with an O/W‐type dispersion of kerosene‐water system in a 154 mm I.D. mixing vessel. The experimental results agree well with the model prediction. Other experimental data in the literature were also adopted for testing the model.
A Semi‐continuous Process for the Synthesis of Methyl Carbamate from Urea and Methanol
Authors: Sun J. , Yang B. , Lin H. 
Published: March 2004

AbstractA semicontinuous process for the synthesis of methyl carbamate from urea and methanol was investigated in the autoclave without the catalyst. Some significant parameters were determined in terms of the methyl carbamate yield. The optimal reaction conditions were found at an initial molar ratio of methanol/urea of 6:1, a reaction temperature of 423 K, a flow rate of fresh methanol at 4 mL/min, a stirring speed of 800 rpm and a reaction time of 6 hours, respectively. A MC yield of 98.7 % was obtained at the optimal reaction conditions. Furthermore, the kinetics of this reaction were researched and the reaction activation energy was obtained as 110.498 kJ/mol. It was demonstrated that removing methanol containing ammonia from the autoclave and replacing it with continuously feeding fresh methanol resulted in a higher reaction rate and a high MC yield.