bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the morphological and rheological properties along the extruder length for compatibilized blends of a commercial liquid‐crystalline polymer and polypropylene
Authors: Filipe S. , Cidade M. T. , Wilhelm M. , Maia J. M. 
Published: October 2005

AbstractIn a previous article, we reported on the evolution of the morphological and rheological properties along the length extruder for blends of a liquid‐crystalline polymer (LCP), Rodrun LC3000, and polypropylene (PP). In this work, we extended this study to compatibilized PP/Rodrun LC3000 blends, containing 10 wt % LCP and different compatibilizers, to determine the influence of the addition of a compatibilizer during the processing and, consequently, on the final properties of such systems. The results revealed that the addition of compatibilizers led to a decrease in the mean diameters of the LCP structures, in comparison with those presented by the noncompatibilized blend containing the same LCP content. This phenomenon occurred more quickly for those blends in which compatibilization was carried out in an efficient way. Linear oscillatory shear was mainly sensitive to the type of morphology present in the blends, whereas nonlinear oscillatory shear was more sensitive to the evolution in the droplet/fibril size and along the extruder length. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 347–359, 2006
Effect of foam density, oil viscosity, and temperature on oil sorption behavior of polyurethane
Authors: Duong Hien T. T. , Burford Robert P. 
Published: October 2005

AbstractThis paper examines the effect of foam density, oil viscosity, and temperature on the oil sorption behavior of polyurethane foams. Four polyurethane foams with different densities and two oil types with different viscosities were investigated. The amount of oil uptake was measured gravimetrically. Oil transport through the foams was analyzed by nondestructive X‐ray microtomography. Oil sorption capacity increased significantly with the decrease in foam density, due to the increase in the number of open cells. The oil sorption capacity depended only slightly on sorption temperature and oil viscosity. X‐ray visualization allowed pore filling behavior to be observed directly, and further scope to extend the technique is revealed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 360–367, 2006
Synthesis and characterization of crosslinked polyurethane dispersions based on hydroxylated polyesters
Authors: Narayan Ramanuj , Chattopadhyay D. K. , Sreedhar B. , Raju K. V. S. N. , Mallikarjuna N. N. , Aminabhavi T. M. 
Published: October 2005

AbstractStringent environmental regulation has endowed dispersible coatings with excellent property profiles in industrial applications. In this aspect, aqueous polyurethane dispersions (PUDs) are of special interest. The present study reports on the synthesis of hydroxylated polyester (HP) based polyurethane polyols containing internal carboxyl group with different diisocyanates. These polyurethane polyols were partly acetoacetylated with ethyl acetoacetate to incorporate β‐ketoester in the polyurethane polyol backbone. The synthesized polyols were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. Polyurethane polyols and their acetoacetylated cousins were used to develop PUDs. Particle size of the reactive PUDs was evaluated by a particle size analyzer. PUDs were crosslinked with hexamethoxy methyl melamine and their film properties were studied by dynamic mechanical and thermal analyzers and thermogravimetric analyses. The effects of different diisocyanate and acetoacetylation on the stability of reactive dispersion and properties of the crosslinked films were evaluated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 368–380, 2006
Kinetic study of the polymerization of ethyl acrylate in an aqueous nitric acid medium
Authors: Ramana Reddy G. V. , Arun J. , Panda Jayakishore 
Published: October 2005

AbstractA kinetic study of the aqueous polymerization of ethyl acrylate (EA) was carried out at 30°C in a dilute nitric acid medium with ammonium ceric nitrate (ACN)–n‐propanol (nPA) and ACN–ethanol as redox initiator systems. The ceric‐ion consumption was first‐order with respect to the ceric‐ion concentration with both initiator systems. The formation of complexes between Ce(IV) and reducing agents was observed. The orders with respect to the Ce(IV), reducing agents, and monomer were evaluated for aqueous polymerizations of EA initiated by Ce(IV)–nPA and Ce(IV)–ethanol redox initiator systems. The overall activation energy for the aqueous polymerization of EA was evaluated in the temperature region of 27–40°C with both initiator systems. A kinetic mechanism for the aqueous polymerization of EA initiated by redox initiator systems is presented. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 218–224, 2006
Improving the transparency of stretched poly(ethylene terephthalate)/polyamide blends
Authors: Prattipati V. , Hu Y. S. , Bandi S. , Mehta S. , Schiraldi D. A. , Hiltner A. , Baer E. 
Published: October 2005

AbstractCompatibilized blends of poly(ethylene terephthalate (PET) with an aromatic polyamide such as poly(m‐xylylene adipamide) (MXD6) have good transparency (T) because the constituent refractive indices (RIs) match closely. However, haziness is observed when the blends are stretched. This study demonstrated that stretching imparted a greater RI anisotropy to PET than to the aromatic polyamide. The resulting RI mismatch was responsible for the loss in T. Analysis of the strain‐dependent birefringence revealed that different molecular deformation models described the intrinsic birefringence of the PET and aromatic polyamides. Hydrogen bonding of the polyamide may have been responsible for the difference. On the basis of these results, three approaches for improving T of stretched PET blends were attempted. Blends with a lower molecular weight MXD6 exhibited slightly higher T after stretching; however, they did not compare with stretched PET. Increasing the amount of compatibilizer reduced the particle size; however, the dimension of even the smallest particles exceeded the quarter wavelength after biaxial stretching transformed the spherical particles into platelets. Copolyamides based on MXD6 that incorporated isophthalate were designed to increase the RI of the polyamide and thereby reduce the RI mismatch with stretched PET. Unexpectedly, the poor T of stretched copolyamide blends was attributed to the high glass‐transition temperature of the copolyamide, which hampered the molecular orientation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 225–235, 2006
Study on the degradation of low‐density polyethylene in the presence of cobalt stearate and benzil
Authors: Roy P. K. , Surekha P. , Rajagopal C. , Raman R. , Choudhary V. 
Published: October 2005

AbstractDegradable polymers are in great demand for a variety of applications such as packaging, agriculture, and medicine. Polyolefins blended with photodegradants/biodegradants are potential candidates for replacing the nondegradable thermoplastics in areas where litter abatement poses problems. In the present article, the effect of metallic photoinitiators like cobalt stearate and a combination of metallic/nonmetallic photoinitiators, i.e., a mixture of cobalt stearate and benzil, on the photooxidative degradation of low‐density polyethylene (LDPE) films have been investigated. Attempts have been made to correlate the results as a function of mixed additives. Films of LDPE containing varying amounts of cobalt stearate and a combination of benzil and cobalt stearate were prepared. The photodegradation of these films has been monitored by various techniques like FTIR spectroscopy, differential thermal analysis, and density and viscosity measurements. Cobalt stearate was highly effective in accelerating the photodegradation of LDPE films at low concentrations. The addition of benzil to cobalt stearate decreased the rate of photodegradation compared to cobalt stearate alone. A retarding effect was observed when benzil alone was added to LDPE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 236–243, 2006
Syntheses of poly(lactic acid‐co‐glycolic acid) serial biodegradable polymer materials via direct melt polycondensation and their characterization
Authors: Wang Zhao‐Yang , Zhao Yao‐Ming , Wang Fang , Wang Jun 
Published: October 2005

AbstractThe optimal synthetic conditions of poly(lactic acid‐co‐glycolic acid) (PLGA) via melt copolycondensation directly from L‐lactic acid (L‐LA) and glycolic acid (GA) with a feed molar ratio of 50/50 are discussed; the important drug‐delivery carrier PLGA50/50 is used as a special example. With reaction conditions of 165°C and 70 Pa and with 0.5 wt % SnCl2 as the catalyst, 10 h of polymerization gave the L‐PLGA50/50 with the biggest intrinsic viscosity ([η]), 0.1993 dL/g. The optimal synthetic conditions were verified by the synthesis of D,L‐PLGA50/50 with D,L‐lactic acid (D,L‐LA) instead of L‐LA, but the biggest [η] was 0.2382 dL/g. Under the same synthetic conditions with L‐LA and D,L‐LA as starting materials, serial PLGA with different molar feed ratios, including 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100, were synthesized via simple and practical direct melt copolycondensation, and their solubilities were investigated. When the glycolic acid feed molar percentage was equal to or more than 70%, solubilities in tetrahydrofuran and CHCl3 became worse, and some samples were even wholly insoluble. These biodegradable polymers were also systematically characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, differential scanning calorimetry, and X‐ray diffraction. PLGA synthesized from L‐LA and D,L‐LA had many differences in weight‐average molecular weight (Mw), glass‐transition temperature, crystallinity, and composition. When the molar feed ratio of LA to GA was 50/50, both the [η] and Mw values of D,L‐PLGA were higher than those of L‐PLGA. With D,L‐LA as the starting material, the structure of the PLGA copolymer was relatively simple, and its properties were apt to be controlled by its GA chain segment. When the feed molar percentage of the monomer (LA or GA) was more than or equal to 90%, the copolymer was apt to be crystalline, and the aptness was more obvious for the L‐LA monomer. The composition percentage of GA in PLGA was not only higher than the feed molar percentage of GA, but also, the GA percentage in D,L‐PLGA was higher than in L‐PLGA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 244–252, 2006
Examination of data relating to the thermodynamic and kinetic interactions between nonvolatile aqueous solutes and three ethylene–vinyl acetate copolymers
Authors: Jenke Dennis R. 
Published: October 2005

AbstractDistribution coefficient (Ks) and diffusivity [diffusion coefficient (D)] values for 19 nonvolatile solutes were previously reported for three ethylene–vinyl acetate (EVA) copolymers. In this article, the interaction properties of these solutes are compared with their octanol/water partition coefficient (Po/w) values. Adequate linear log/log correlations between Ks and Po/w are obtained for all three copolymers, once the effect of the solution pH on solute speciation is taken into account. The resultant correlations are similar for all three copolymers, suggesting that they share a common interaction mechanism. Inverse correlations between log D and log Po/w are established for all three materials. Although the relationship between log D and log Po/w is linear for the EVA polymers, the scatter in the poly(vinyl acetate) data is sufficiently large that a linear relationship cannot be unilaterally established. The utility of such a model in terms of assessing the potential interaction between a plastic container and its contained contents is demonstrated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 253–259, 2006
Adsorption and desorption properties of cationic polyethylene film gels to organic anions and their regeneration
Authors: Yamada Kazunori , Shibuya Masanao , Takagi Chiyo , Hirata Mitsuo 
Published: October 2005

AbstractAn investigation was undertaken on the adsorption and desorption properties of 2‐(dimethylamino)ethyl methacrylate grafted polyethylene (PE‐g‐PDMAEMA) films to anionic dye anions with one to three sulfonic groups in response to pH and temperature changes. The amounts of dye anions adsorbed on the PE‐g‐PDMAEMA films passed through the maximum values at about pH 3 because of an increase in the protonation of dimethylamino groups caused by a decrease in the pH value. The amounts of adsorbed dye anions decreased below pH 3 because the ionic strength increased with the addition of HCl to adjust the initial pH values of the aqueous dye solutions. The amounts of adsorbed dye anions decreased with an increase in the number of sulfonic groups in the dye molecules at the same pH value because electrostatic repulsion was generated between free sulfonic groups of the dye anions adsorbed onto the PE‐g‐PDMAEMA films and free dye anions in the medium. A large number of dye anions adsorbed were desorbed from the PE‐g‐PDMAEMA film with initial pH values above 11.0. The cyclic processes of adsorption at pH 3.0 and desorption at pH 11.0 were repeated without considerable fatigue. The PE‐g‐PDMAEMA films showed practically regenerative adsorption and desorption behavior in response to the pH changes. In addition, when the dye‐anion‐adsorbed PE‐g‐PDMAEMA films were alternately immersed in water at two different temperatures, dye anions were desorbed in water at higher temperatures without any chemical agents because of the deprotonation of dimethylamino groups and thermosensitive contraction of grafted PDMAEMA chains. These results indicate that PE‐g‐PDMAEMA films can be applied as regenerative ion‐exchange membranes for adsorption and desorption processes of anionic compounds in response to the pH and temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 381–391, 2006
Determination of the methyl methacrylate monomer in its polymer latex by headspace gas chromatography
Authors: Chai X.‐S. , Hou Q. X. , Schork F. J. 
Published: October 2005

AbstractThis article reports a headspace gas chromatography (GC) method for the determination of the residual monomer in a methyl methacrylate polymer latex or emulsion. Because of the multiphase nature of a polymer latex, the level of the residual monomer cannot be quantified by headspace GC on the basis of its vapor–liquid equilibrium (VLE) without significant thermodynamic assumptions. With a significant dilution of a polymer latex sample followed by vapor–liquid equilibration at an elevated temperature, the monomer droplets are completely dissolved in the aqueous phase, and monomer absorption in the polymer particles can be minimized. Thus, VLE is established in the diluted latex, and a linear relationship between the monomer concentration in the vapor and aqueous phases can be obtained. This technique eliminates sample pretreatment procedures such as solvent extraction in the conventional GC method, and it avoids the risk of polymer deposition on the GC column caused by a direct injection of a monomer‐containing solvent. It also eliminates the possibility of solvent interference in the conventional GC monomer analysis. This method is simple, accurate, and automated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 392–397, 2006
Preparation and characterization of polyimide‐g‐nylon 6 copolymers from nonfunctionalized polyimides
Authors: Pae Youlee 
Published: October 2005

AbstractIn this research, the anionic polymerization of ϵ‐caprolactam was carried out in the presence of small amounts of several different polyimides to generate polyimide‐g‐nylon 6 copolymers. The polyimides, which were prepared from 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride and commercially available diamines with a one‐step method, were first dissolved in molten ϵ‐caprolactam. Phenylmagnesium bromide was then added at 120°C. Under these conditions, caprolactam anions were formed that attacked the five‐membered imide rings to form N‐acyllactam moieties, which activated the anionic polymerization of caprolactam. In essence, nylon 6 chains grew from the polyimide backbones. Probably because of a high activation energy, the process was relatively slow, requiring 1 h at 120°C. The introduction of 5 wt % polyimide into the graft copolymers produced significant increases in the tensile modulus and tensile strength in comparison with those of low‐ and high‐molecular‐weight nylon 6. The elongation to break, however, was reduced. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 292–299, 2006
Structure and properties of polyimide‐g‐nylon 6 and nylon 6‐b‐polyimide‐b‐nylon 6 copolymers
Authors: Pae Youlee 
Published: October 2005

AbstractPolyimide‐g‐nylon 6 copolymers were prepared by the polymerization of phenyl 3,5‐diaminobenzoate with several diamines and dianhydrides with a one‐step method. The polyimides containing pendant ester moieties were then used as activators for the anionic polymerization of molten ε‐caprolactam. Nylon 6‐b‐polyimide‐b‐nylon 6 copolymers were prepared by the use of phenyl 4‐aminobenzoate as an end‐capping agent in the preparation of a series of imide oligomers. The oligomers were then used to activate the anionic polymerization of ε‐caprolactam. In both the graft and copolymer syntheses, the phenyl ester groups reacted quickly with caprolactam anions at 120°C to generate N‐acyllactam moieties, which activated the anionic polymerization. All the block copolymers had higher moduli and tensile strengths than those of nylon 6. However, their elongations at break were much lower. The graft copolymers based on 2,2′‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride and 2,2′‐bis[4‐(4‐aminophenoxy)phenyl]propane displayed elongations comparable to that of nylon 6 and the highest moduli and tensile strengths of all the copolymers. The thermal stability, moisture resistance, and impact strength were dramatically increased by the incorporation of only 5 wt % polyimide into both the graft and block copolymers. The graft and block copolymers also exhibited improved melt processability. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 300–308, 2006
Using multiple‐mode models for fitting and predicting rheological properties of polymeric melts
Authors: Jiang B. , Kamerkar P. A. , Keffer D. J. , Edwards B. J. 
Published: October 2005

AbstractSeveral classes of multiple‐mode rheological constitutive equations are tested for fitting and predicting viscoelastic flow properties of a typical low‐density polyethylene melt. An optimization procedure is used to fit the phenomenological parameters of each model under consideration to experimental data taken in small‐amplitude oscillatory shear flow and steady shear flow. These parameter values are then used to generate predictions for transient shear and uniaxial elongational flow experiments, and the predictions are then compared to experimental data. Model successes and failures are discussed, and the outlook for using rheological equations in real design processes is addressed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 405–423, 2006
Looking back versus looking ahead: framing of time and work at different stages of a project
Authors: Teigen Karl Halvor , Karevold Knut Ivar 
Published: October 2005

AbstractProgress on a well‐defined project can be described along a task dimension in terms of amount done, or as amount of work still to be completed. Time‐limited projects can also be described on a temporal dimension in terms of time spent versus time left. Five experiments are reported showing that such frames have predictable implications for speakers as well as for listeners: Statements by a team leader about time spent and work left are perceived as suggestions to “hurry up,” whereas complementary statements about work done and time left indicate that the team can take it more easy. The first set of statements further implies that the team is behind schedule, whereas the last two statements suggest that the team is ahead of the plan. In line with this, speakers preferred work done and time left statements when they were ahead of schedule, but not when they were behind. “Hurry up” and “behind schedule” interpretations were also shown to be dependent upon stage, being more prominent in the final stages than during the initial stages of a project. Copyright © 2005 John Wiley & Sons, Ltd.
Contingent approaches to making likelihood judgments about polychotomous cases: the influence of task factors
Authors: Windschitl Paul D. , Krizan Zlatan 
Published: October 2005

AbstractTwo experiments tested the influence of three task factors on respondents' tendency to use normative, heuristic, and random approaches to making likelihood judgments about polychotomous cases (i.e., cases in which there is more than one alternative to a focal hypothesis). Participants estimated their likelihood of winning hypothetical raffles in which they and other players held various numbers of tickets. Responding on non‐numeric scales (vs. numeric ones) and responding under time pressure (vs. self‐paced) increased participants' use of a comparison‐heuristic approach, resulting in non‐normative judgment patterns. A manipulation of evidence representation (whether ticket quantities were represented by numbers or more graphically by bars) did not have reliably detectable effects on processing approaches to likelihood judgment. The authors discuss the implications of these findings for the further development of likelihood judgment theories, and they discuss parallels between contingent processing in choice and contingent processing in likelihood judgment. Copyright © 2005 John Wiley & Sons, Ltd.
Studies of folded peptide‐based catalysts for asymmetric organic synthesis
Authors: Blank Jarred T. , Miller Scott J. 
Published: October 2005

AbstractFolded peptides have proven to be a fertile area for discovery of catalysts for reactions in organic synthesis. Both combinatorial chemistry and rational design have fueled these discoveries. In both lines of research, mechanistic studies following the discovery of selective reactions have led to structural information that has stimulated attempts to correlate peptide structure and the relay of stereochemical information. Thus, key elements of the design of peptide‐based catalysts include the identification of catalytically competent functional groups and their incorporation into three‐dimensional structures that provide an appropriate chiral environment. Of note, turns, helices, nonobvious folds, and still undetermined secondary structures characterize the structural and functionally diverse motifs that enable peptide‐catalyzed asymmetric reactions to occur. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 38–47, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com