bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface modification of HDPE and PP by mechanical polishing and DC glow discharge and their adhesive joining to steel
Authors: Bhowmik S. , Ghosh P. K. , Ray S. 
Published: August 2002

AbstractTo improve the strengths of the adhesive joints of high density polyethylene (HDPE) and polypropylene (PP) to steel, the surfaces of HDPE and PP sheets have been treated by DC glow discharge to increase the polar component of surface energy significantly. Present study investigates the effect of mechanical polishing prior to surface modification of substrates of HDPE and PP sheets by exposure to DC glow discharge, on the surface energy and their adhesive joint strength to steel. The mechanical polishing has been carried out by abrading with 120, 220, 400, 600, 800, and 1000 grade emery paper of grit sizes 8.33, 4.54, 2.5, 1.67, 1.2, and 1 micron, respectively. The surface energy of a given surface has been evaluated by measuring contact angles of sessile drops of two test liquids of known surface tension components, such as deionized water and formamide. It is observed that 800‐grade emery paper of grit size 1.2 micron has been found most effective in terms of their reduction in contact angles and enhancement of their surface energies. The change in surface energy due to surface modification has also been evaluated by measuring the surface energies of unpolished sheets exposed to DC glow discharge. The surface modification of the polymers by glow discharge for 120 s at a power level of 13 W decreases the contact angle more on mechanically polished specimens than that observed on unpolished sheets. Due to glow discharge treatment, the polar component of surface energy increases significantly in HDPE and PP, especially when they are mechanically polished (800 grade) prior to glow discharge. However, in case of the HDPE sheets, the effect of glow discharge on the polar component of surface energy is significantly higher compared to that for dispersion component of surface energy, whereas the polar component of surface energy of the PP sheet is lower than the dispersion component of surface energy. But in both the cases, mechanical polishing prior to glow discharge appears to affect the polar component of surface energy. Mechanical polishing of the HDPE and PP sheets by abrading with 800‐grade emery paper prior to glow discharge treatment, increases the adhesive joint strengths over those observed in case of unpolished polymers exposed to glow discharge. However, the use of prior mechanical polishing increases the joint strength only by a little more than 10% compared to a five to seven times increase in strength observed as a consequence of exposure to glow discharge of as received samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1140–1149, 2001
The development of controllable complex curing agents for epoxy resins. I. Preparation, characterization, and storage behavior of transition metal–diamine complexes
Authors: Hamerton Ian , Hay John N. , Howlin Brendan J. , Jepson Peter , Mortimer Stephen 
Published: August 2002

AbstractA series of complexes incorporating diamine (o‐phenylene diamine and 2‐aminobenzylamine—OPD and 2‐ABA respectively) ligands and containing the acetato and chloro transition metal salts of Ni and Cu has been prepared and characterized using elemental analysis and spectroscopic methods. Infrared data show that complexation of the amino nitrogen atoms occurs to a high degree. The same curing agents have been incorporated into two commercial epoxy resins recognized as “industry standards” (MY721 and MY750), and their cure properties and shelf life assessed alongside commercial curative systems. The current work demonstrates that while complexes based on copper(II) and nickel(II) and containing OPD ligands may be prepared and incorporated into commercial epoxy resins, there are some advantages associated with using 2‐ABA (as the diamine ligand) due to the higher complex solubility and better processing characteristics that it imparts to the formulated system. In general, the 2‐ABA based complexes disperse well within commercial epoxy systems and display good storage stability over prolonged periods of time (up to 67 days at ambient temperature). Work continues to examine the thermal and mechanical characteristics of commercial epoxy resins cured using these complexes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1489–1503, 2001
Preparation and characterization of macroporous phenol‐furfural sulfonic acid resin catalyst
Authors: Su Zhixing , Li Yuntao , Miao Yuanzhao , Wang Tiejun , Pu Qiaosheng 
Published: August 2002

AbstractThe macroporous phenol‐furfural sulfonic acid resin catalyst (PFuSR) was prepared. The resin was characterized by chemical analysis, thermal analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and reactions of esterification. There exist in PFuSR different kinds of acidic groups such as OH, COOH, and SO3H. The catalytic relative activity of PFuSR in the reaction of acetic acid and n‐butanol is 104 times that of macroporous polystyrene sulfonic acid resin D72. Thermal analysis showed that PFuSR did not begin to desulfonate until temperatures of 220°C were reached. The resin is suitable for use continually up to 200°C, verified by successfully performing the reaction of maleic anhydride with 2‐ethyl‐1‐hexanol to form di‐2‐ethylhexyl maleate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1764–1769, 2001
Kinetics of mesophase transition of lyotropic chitosan in dichloroacetic acid
Authors: Hu Zhongming , Wu Liheng , Wu Dacheng , Chen Shouxi 
Published: August 2002

AbstractThe mesophase transition and its kinetics of chitosan in the solutions of chitosan/dichloroacetic acid (DCA) were investigated by means of DSC and depolarized light intensity technique, respectively. The mesophase formation of chitosan in DCA involves nucleation and growth. The isothermal kinetics of mesophase formation from isotropic phase were described by Avrami using the equation with an exponent n close to 1, which suggests that the formation of chitosan mesophase is a process of instantaneous nucleation and one‐dimensional rod‐like growth in the temperature range investigated. This was confirmed by small angle light scattering Hv patterns of the mesophase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1770–1775, 2001
Precision associated with determination of dirt content of natural rubber
Authors: Ehabe E. , Ngolemasango F. , Bonfils F. , Sainte‐Beuve J. 
Published: August 2002

AbstractThe precision associated with determination of dirt in natural rubber is low even when similar testing procedures are applied. All measurements leading to this estimation involve the use of an analytical balance. For this reason the contribution of associated errors to the ultimate precision of dirt measurements was evaluated using analytical balances of varying degrees of precision. A mathematical model was proposed to estimate the compound standard error associated with dirt measurements, which was found to be ±0.001 mg. This signifies that, during dirt assay, the masses of test portions, empty sieves, and sieves containing dirt must be estimated to at least 3 significant figures. This error would further decrease with an increase in the quantity of dirt assayed. Prolonged maturation of coagula reduced the length of rubber chains, thus increasing the ease of dissolution of test portions during dirt analysis. Higher molar mass samples were mostly associated with poor reproducibility of dirt and macrogel content determinations. Increasing the mass of test portions improved the precision of dirt measurements, though the recommended sizes of these portions should be a compromise of economic considerations and practical testing conditions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 957–962, 2001
Phosphate‐containing flame‐retardant polymers with good compatibility to polypropylene. I. The effect of phosphate structure on its thermal behavior
Authors: Chiang Wen‐Yen , Hu Howard C.‐H. 
Published: August 2002

AbstractPhosphate‐containing flame‐retardant polymers were synthesized via a partial‐substitution reaction of poly(vinyl acetate) with stearylphosphonic chloride (SPPC) and diethylchlorophosphate in various substitution ratios. SPPC had been previously synthesized from phosphonic dichloride and stearyl alcohol. The synthesized SPPC and the flame‐retardant polymer products were characterized by Fourier transform infrared (FTIR) spectra analysis. The quantitative analysis of phosphorus in the polymer products was carried out by EDS (Energy Dispersion Spectrummeter) analysis. The real substitution ratios of the polymer products were estimated by the atomic number ratio of carbon and phosphate in products from EDS data. Variations in the glass‐transition temperature and thermal‐decomposition temperature of the products were investigated. The char of polymer products produced after thermogravimetric analysis (TGA) was also analyzed by FTIR, and the results show that different phosphate substitution leads to different char developments during the heating of TGA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1125–1135, 2001
Cyclic acetals: Synthesis and polymerization
Authors: Socha František , Dobáš Ivan , Šňupárek Jaromír 
Published: August 2002

AbstractMixtures of 5‐membered and 6‐membered 2‐vinyl (2‐propenyl or 2‐isopropyl)‐4‐hydroxymethylene or 5‐hydroxy‐substituted cyclic acetals were synthesized by the reaction of aldehydes with glycerol. Reesterification of the hydroxyl group in position 4 or 5 was achieved using methyl methacrylate. The compounds were subjected to radical copolymerization using different initiating systems. Both radical copolymerization and ring cleavage were observed to be dependent on the reaction conditions. The ring cleavage was confirmed on model compounds of 2‐substituted 5‐membered and 6‐membered cyclic acetals without any polymerizable substituent. The rate of the ring opening was measured and compared to the rate of copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2875–2880, 2001
Monomer consumption rates during gelation at various temperatures: A fast transient fluorescence study
Authors: Pekcan Ö. , Kaya D. 
Published: August 2002

AbstractThe gelation during free‐radical crosslinking copolymerization (FCC) of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM) was studied by using fast transient fluorescence (FTRF) technique. Pyrene (Py) was used as a probe for the FTRF experiments. Fluorescence lifetimes of Py from its decay traces were measured and used to monitor the gelation process at various temperatures. MMA consumption rates were measured during gelation process by using the Stern–Volmer model. Gelation activation energy ΔEG was measured and found to be 15.6 kcal mol−1. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3161–3168, 2001
Copolymers of chosen alkyl methacrylates with N‐phenylmaleimide and N‐(4‐halogenphenyl)maleimides: A UV‐aging study
Authors: Ryttel Anna 
Published: August 2002

AbstractHomopolymers and copolymers of ethyl and butyl methacrylates with N‐phenylmaleimide, N‐(4‐chlorophenyl)maleimide, and N‐(4‐bromophenyl)maleimide were synthesized by free‐radical bulk polymerization with benzoyl peroxide as the initiator. The content of imide in the copolymers was about 5–10 or 7.5 wt %. The homopolymers and copolymers were irradiated with ultraviolet (UV) light in a climatic test chamber for various periods to study their aging behavior. After 100, 250, and 500 h, the structure, thermal stability, chemical resistance, and some physicomechanical properties were examined. The influence of UV radiation time on structure and the investigated properties of the homopolymers and copolymers were studied. The experimental results indicate that all investigated copolymers were resistant to UV radiation after 500 h. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3244–3250, 2001
Synthesis and characterization of poly(N‐vinyl pyrrolidone‐alt‐maleic anhydride): Conjugation with bovine serum albumin
Authors: Veron L. , Revol M. , Mandrand B. , Delair T. 
Published: August 2002

AbstractAlternate N‐vinyl pyrrolidone/maleic anhydride (NVPMA) copolymers were obtained by radical solution polymerization in dioxane with various MA contents in the monomer feed. The conversion of each monomer was monitored by proton nuclear magnetic resonance spectroscopy (1H NMR), and the kinetics investigation showed that both monomers had identical polymerization rates if both monomers were present in the reaction mixture. The presence of excess NVP in the polymerization medium increased the kinetics of the polymerization and the molar masses of the resulting polymers. This increase was attributed to a cosolvent effect due to NVP, which is a better solvent for the polymer than dioxane. The hydrolysis rate constant of the polymers increased with pH, and NVPMA copolymers were more prone to hydrolysis (by a factor 10) than the methyl vinyl ether ones. Finally, the immobilization of bovin serum albumin (BSA) was investigated. A 25 mM phosphate buffer (pH 5.5) was the best medium to covalently bind 5 BSA molecules onto a 29 kDa NVPMA copolymer and 13 BSA molecules onto a 58 kDa sample, with grafting efficiencies > 90%. Noncovalent interactions with the hydrolyzed form of the polymer and BSA occured at pHs lower than the isoelectric point of BSA, and the resulting complexes were insoluble in water. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3327–3337, 2001
Synthesis and characterization of sulfonated poly(phenylene oxides) as membranes for polymer electrolyte membrane fuel cells
Authors: Vishnupriya B. , Ramya K. , Dhathathreyan K. S. 
Published: August 2002

AbstractThe synthesis of a thermally stable proton conducting polymer based on poly(phenylene oxide) (PPO) was carried out using 2,6‐dimethylphenol (DMP) and 2‐allylphenol (AP) as monomers. The copolymers using the two monomers were prepared with DMP to AP molar ratios of 20:80, 40:60, 60:40, and 80:20. The polymers and the copolymers were blended with poly(vinylidene fluoride) and cast as membranes. All the membranes were sulfonated and characterized for their suitability as a polymer electrolyte membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1792–1798, 2002
Oxygen enrichment from air through multilayer thin low‐density polyethylene films
Authors: Huang Mei‐Rong , Li Sheng‐Xian , Dong Zhi‐Qing , Feng Wei , Wang Xin‐You , Gu Shu‐Ying , Wu Yan‐Hui , Huang Xiang‐An 
Published: August 2002

AbstractSeveral multilayer thin low‐density polyethylene (LDPE) films were fabricated by blown thin film having a thickness of 7 μm and an area of 130 cm2. They were characterized for their oxygen‐enrichment performance from air by a constant pressure–variable volume method in a round permeate cell with an effective area of 73.9 cm2. The relationship between oxygen‐enrichment properties, including oxygen‐enriched air (OEA) flux, oxygen concentration, permeability coefficients of OEA, oxygen, nitrogen, as well as separation factor through the multilayer LDPE films, and operating parameters, including transfilm pressure difference, retentate/permeate flux ratio, temperature, as well as layer number, are all discussed in detail. It is found that all of the preceding oxygen‐enrichment parameters increase continuously with an increase of transfilm pressure difference from 0.1 to 0.65 MPa, especially for the trilayer and tetralayer LDPE films. The oxygen concentration and separation factor appear to rapidly increase within the retentate/permeate flux ratio below 200, and then become unchangeable beyond that, whereas the OEA flux and the permeability coefficients of OEA, oxygen, and nitrogen seem to remain nearly constant within the whole retentate/permeate flux ratio investigated, especially for the monolayer and bilayer LDPE films. The selectivity becomes inferior, whereas the permeability becomes superior, as the operating temperature increases from 23 to 31°C. The highest oxygen concentration was found to be 44.8% for monolayer LDPE film in a single step with air containing oxygen of 20.9% as a feed gas and operating pressure of 0.5 MPa at a retentate/permeate flux ratio of 340 and 23°C. The results demonstrate a possibility to prepare an oxygen‐enriching membrane directly from air, based on the easily obtained thin LDPE films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3013–3021, 2002; DOI 10.1002/app.2331
Establishing management schemes on marine Special Areas of Conservation in Scotland
Authors: Baxter John M. 
Published: August 2002

Abstract1. The challenges and critical points in the development of a management scheme for a marine Special Area of Conservation (SAC) are discussed.2. The need for sufficient information to justify the selection of an area and, subsequently, to inform any debate on management decisions and a monitoring programme, together with the requirement to make such information readily and widely available are highlighted.3. The development of a management scheme should be inclusive and involve all interested parties, so that there is ultimately as wide as possible ownership of the scheme.4. It is important that sufficient opportunity is given for all issues to be adequately investigated, discussed and resolved. A realistic but flexible timetable needs to be set at the beginning of the process with a clear understanding by all those involved that there is a definite end point to this process.5. The importance of identifying the potential benefits of marine SACs, and not just the possible constraints, is important in achieving these overall goals. Copyright © 2001 John Wiley & Sons, Ltd.
Cuticular hydrocarbons of the ectoparasitic wasp Cephalonomia hyalinipennis (Hymenoptera: Bethylidae) and its alternative host, the stored product pest Caulophilus oryzae (Coleoptera: Curculionidae)
Authors: Howard Ralph W. , Pérez‐Lachaud Gabriela 
Published: August 2002

AbstractCuticular hydrocarbons of an ectoparasitic wasp attacking two beetle hosts have been identified and examined for the influence of age, gender, mating status, and host on hydrocarbon composition. The 37 wasp hydrocarbons identified consisted of a series of n‐alkanes (C16 to C33), 3‐, 5‐, 9‐, 10‐, 11‐, and 12‐methyl alkanes and a series of Z‐7 and Z‐9 monoenes (C23:1 to C27:1). One C25:2 diene was found. No effects of hydrocarbon composition as a function of age, gender, or mating status were found for the wasps. Wasps reared on Hypothenemus hampei, however, had 12/37 significant abundance differences to those reared on Caulophilus oryzae, although all but one of these differences were for components in less than 2% relative abundance. The C25:2 diene from wasps reared on H. hampei was present in about 10% whereas from wasps reared on C. oryzae it was present in about 2%. The hydrocarbons of one host for this wasp, the coffee berry borer (Coleoptera: Scolytidae), have been previously reported [Howard and Infante, Ann. Entomol. Soc. Am. 89:700–709 (1996)]. The hydrocarbons of the alternative host, C. oryzae (Coleoptera: Curculionidae) consists of n‐alkanes (C17 to C31), 3‐, 4‐, 5‐, 7‐, 9‐, 11‐, 12‐, 13‐, 14‐, and 15‐methyl alkanes, and a series of dimethyl alkanes of the series 3, 17‐; 5, 11‐; 5, 17‐; 7, 11‐; 7, 13‐; 13, 17‐; and 15, 19‐. No unsaturated hydrocarbons were found. No significant differences in hydrocarbon composition were found between male and female C. oryzae. Hydrocarbon patterns of four species of Cephalonomia are compared and shown to be species‐specific. The data are discussed in terms of ecological and physiological parameters. Arch. Insect Biochem. Physiol. 50:75–84, 2002. Published 2002 Wiley‐Liss, Inc.
Pharmacokinetic assessment of an oral enalapril suspension for use in children
Authors: Rippley Ronda K. , Connor John , Boyle Janet , Bradstreet Thomas E , Hand Elizabeth , Lo Man‐Wai , Murphy M. Gail 
Published: August 2002

AbstractThe angiotensin‐converting enzyme (ACE) inhibitor enalapril is commonly used to treat pediatric hypertension. Because some children are unable to swallow tablets or require doses less than the lowest available enalapril tablet, an enalapril suspension was developed. This study examined the relative bioavailability of enalapril suspension (10 mg) (S) compared with 10‐mg marketed VASOTEC™ tablets (T) in 16 healthy adult subjects. The geometric mean ratio (S/T) estimate of urinary recovery of free enalaprilat, the active moiety, was 0.92 (90% confidence interval (CI): 0.80, 1.07). Urinary recovery data indicate that approximately 50% of the dose was absorbed (50% recovered in urine as enalapril plus enalaprilat) with about 30% of the dose recovered as free enalaprilat for both S and T. The geometric mean ratios (S/T) of serum AUC and Cmax were 1.01 (90% CI: 0.90, 1.13) and 0.98 (90% CI: 0.83, 1.16), respectively. Suspension Tmax was slightly shorter (0.5 h) than that for tablet, but this difference is not clinically significant. Both formulations were well tolerated and there were no clinically significant adverse experiences. We conclude that the bioavailability of enalapril oral suspension 10‐mg is similar to that of VASOTEC™ 10‐mg tablet. Instructions for compounding enalapril are provided. Copyright © 2000 John Wiley & Sons, Ltd.
Effects of extremely low frequency (50 Hz) magnetic field on morphological and biochemical properties of human keratinocytes
Authors: Manni Vanessa , Lisi Antonella , Pozzi Deleana , Rieti Sabrina , Serafino Annalucia , Giuliani Livio , Grimaldi Settimio 
Published: August 2002

AbstractWe investigated the effects on human keratinocytes (HaCaT) of exposure to a sinusoidal magnetic field of 2 mT (50 Hz). These cells are a good model for studying interaction of nonionising radiation, because they are not shielded from fields in vivo and also because they are resistant to both mechanical and thermal stimuli. We performed scanning microscopy which showed modification in shape and morphology in exposed cells. This modification is related to differential actin distribution as revealed by phalloidin fluorescence analysis. Moreover, the exposed cells show increased clonogenic capacity, as well as increased cellular growth as showed by clonogenicity assays and growth curves. Indirect immunofluorescence analysis using a fluorescent antibody against involucrin and β4 integrin, which are respectively differentiation and adhesion markers, revealed an increase of involucrin expression and segregation of β4 integrin in the cell membrane in cells exposed to 50 Hz; a higher percentage of the exposed cells shows a modified pattern of adhesion and differentiation markers. We also present evidence that exposure of HaCaT cells can interfere with protein kinase activity. Our observations confirm the hypothesis that electromagnetic fields at 50 Hz may modify cell membrane morphology and interfere with initiation of the signal cascade pathway and cellular adhesion. Bioelectromagnetics 23:298–305, 2002. © 2002 Wiley‐Liss, Inc.
Comparison of nitrophenylethyl and hydroxyphenacyl caging groups
Authors: Du Xinlin , Frei Heinz , Kim Sung‐Hou 
Published: August 2002

AbstractNitrophenylethyl (NPE)‐ and hydroxyphenacyl (HPA)‐caged nucleotides were employed in a time‐resolved Fourier transform IR spectroscopy study on Ras‐catalyzed guanosine triphosphate (GTP) hydrolysis. A fast kinetic component was observed following the photolysis of NPE‐caged nucleotides in the NPE‐GTP‐Ras complex. However, this kinetic component was not observed in the HPA‐GTP‐Ras experiment. This fast kinetic component was likely due to a chemical reaction between Ras and the detached caging group, nitrosoacetophenone. This communication serves as a note of caution in interpreting spectral changes and kinetic behavior of the enzymatic systems employing NPE‐caged compounds. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 147–149, 2001