bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soap‐free seeded emulsion copolymerization of MMA onto PU‐A and their properties
Authors: Zhang Hong Tao , Guan Rong , Yin Zhao Hui , Lin Liu Lan 
Published: October 2004

AbstractThe polyurethane acrylate (PU‐A) containing double bond and COOH group was synthesized by stepwise reaction of 2,4‐toluene diisocyanate (TDI), polyetherdiol (PPG), dimethylolpropionic acid (DMPA), and 2‐hydroxpropyl acrylate (HPA), and the PU‐A was neutralized with triethylamine (TEA) and self‐emulsified in water to form the PU‐A emulsion seed. Adding methyl methacrylate (MMA) into PU‐A seed, the seeded emulsion copolymerization of MMA onto PU‐A seed had been carried out at 80°C under the soap‐free condition to obtain anionic latex of P(UA‐MMA). The kinetic behavior of the seeded emulsion copolymerization, the MMA grafting ratio, and the crosslinking copolymer were investigated. IR spectra showed that it did form the P(UA‐MMA) copolymer. The measurements revealed that the structure of the P(UA‐MMA) copolymer, its latex properties and the cast film were significantly influenced by the amounts of HPA, DMPA, and MMA. The experimental results indicated that with DMPA increased, the particle size of P(UA‐MMA) latex decreased, but the tensile strength of its cast film increased. Adding a small amount of HPA, it could improve the tensile strength of the cast film. With MMA content increased, the distribution of the particle size of P(UA‐MMA) latex became narrow, whereas under certain amount of MMA, the tensile strength of the cast film was enhanced. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 941–947, 2001
Effect of radiation on the friction‐wear properties of polyetherketone with a cardo group
Authors: Tian Nong , Li Tongsheng , Liu Xujun , Liu Weimin 
Published: October 2004

AbstractWe studied the effect of radiation on the friction‐wear properties of polyetherketone with a cardo group (PEK‐C) with a MM‐200 model friction and wear tester. We found that radiation could improve the friction‐wear properties of PEK‐C to a certain degree. The friction coefficient and wear rate of PEK‐C decreased as the radiation dose increased from 5 × 104 to 1 × 107 Gy. Scanning electron microscopy results revealed that the size of wear debris of unirradiated PEK‐C was larger than that of irradiated PEK‐C. The worn surface of unirradiated PEK‐C showed plough marks, whereas the worn surface of irradiated PEK‐C did not show plough marks; its surface was quite smooth. With the frictional couple of a carbon steel ring and an irradiated PEK‐C block, a relatively uniform and coherent transfer film was formed on the ring surface. It was inferred that the transfer film contributed largely to the decreased friction coefficient and wear rate of the irradiated PEK‐C. An IR spectrum showed that no significant chemical change took place when the PEK‐C sample was irradiated. Thermal analysis results showed that radiation changed the thermal properties of PEK‐C, therefore, its friction‐wear properties changed at the same time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 962–967, 2001
High‐performance polymer films. III. Preparation and characterization
Authors: Khatua Sankar C. , Maiti Sukumar 
Published: October 2004

AbstractA series of polyimide and copolyimide films were prepared by film casting, drying, and thermal imidization from the respective precursor poly(amic acid) (PAA) and copoly(amic acid) solutions derived from two dianhydrides, pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), and two diamines, 4,4′‐oxydianiline (ODA) and a proprietary aromatic diamine (PD) as monomers. Depending on the solution's inherent viscosity value (molecular weight) and the nature of the polymer chains (derived from rigid or flexible monomers), precursor poly(amic acid) and copoly(amic acid) solution concentrations of 8–12% (w/w) were found to be suitable for the preparation of good quality polyimide/copolyimide films. The recovery of film toughness and creasability from the brittleness at the intermediate temperature of the cure cycle depended not only on the molecular weight of the precursor poly(amic acids)/copoly(amic acids) but also on their chain flexibility. The poly(amic acid) derived from both rigid dianhydride and diamine practically gave rise to a brittle film of polyimide even after curing to 360°C. The resulting polyimide and copolyimide films were compared with Du Pont's Kapton H film. The density of the films was in the range 1.39–1.42 g/cm3. The thickness of most of the films was in the range 20–30 μm. The HPF 3 film, based on PMDA–PD, appeared to be highly colored (reddish brown), and the HPF 2 film, based on BTDA–ODA, had the lightest yellow coloring among the films in this investigation, including Kapton H film. HPF 2, HPF 6, and HPF 8 films were more amorphous than the other films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 976–988, 2001
Infrared dichroism and birefringence studies of silica‐filled styrene–butadiene rubbers
Authors: Bokobza L. , Ladouce L. , Bomal Y. , Amram B. 
Published: October 2004

AbstractInfrared and birefringence measurements are used to characterize the orientational behavior of silica‐filled styrene–butadiene copolymers. The orientational data are correlated with the results of equilibrium swelling measurements. On the other hand, the role played by a silane couling agent bis(3‐triethoxysilylpropyl)tetrasulfide (TESPT), or “Si69”) on rubber/silica system is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1006–1012;2001
Surface‐active properties of hydrophobized derivatives of lignosulfonates: Effect of structure of organosilicon modifier
Authors: Telysheva G. , Dizhbite T. , Paegle E. , Shapatin A. , Demidov I. 
Published: October 2004

AbstractAn investigation of regularities of surface‐tension alterations in the aqueous solutions of lignosulfonate and aluminum‐containing organosilicon oligomer (olygoheterosiloxanolates) reaction mixtures revealed that modification with oligomers can be used for the regulation of the surface activity of lignosulfonates. High surface activity not only in acidic, but also in neutral and alkali media, is achieved using oligomers which consist of ethylsesquioxane and diethylsiloxane links. In this case, increasing hydrophobicity compensates the negative effects (increase of solubility and the Coulomb repulsion) of ionization of lignosulfonate acidic groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1013–1020, 2001
Copolymerization behavior of 3‐isopropenyl‐α,α‐dimethylbenzylamine and a preliminary evaluation of the copolymers in thermoset coatings
Authors: Trumbo D. L. , Mote B. E. , Trevino A. S. , van den Brink M. 
Published: October 2004

AbstractThe title monomer was synthesized from 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate in a significantly better yield than was previously reported. 3‐Isopropenyl‐α,α‐dimethylbenzylamine proved incapable of homopolymerization using free‐radical initiation but readily copolymerized with a variety of commonly available monomers under free‐radical conditions. Films of some of the copolymers were prepared and crosslinked using a variety of multifunctional epoxy compounds. The films had good solvent resistance, high hardness, and good gloss. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1030–1039;2001
Raman microimaging study of interfacial profiles of hydrogels
Authors: Zerda T. W. , Appel Rainer , Hu Zhibing 
Published: October 2004

AbstractA Raman microimaging technique was used to directly observe the interfacial profile between N‐isopropylacrylamide (NIPA) and polyacrylamide (PAAM) hydrogels in water. The joined hydrogels are called bigels and are synthesized by penetrating the PAAM gel into a part of the NIPA gel network. The bigel strip contains about 97 wt % water at room temperature. The study reveals how different manufacturing parameters, such as the drying time of the NIPA substrate and the diffusion time of the PAAM pregel solution into the NIPA layer, influence the properties and extent of the bigel interface. The interface becomes thicker with increased drying time. Specifically, the average interfacial thickness of the interface after 2 h of drying is about 28 μm, but increases to 156 μm after 16 h of drying time. The extent of the interface is independent of the PAAM diffusion time. The penetration of the PAAM pregel solution into the pores of the NIPA gel is completed in less than 30 min. The topography of the surface can be well characterized by a Gaussian function with the correlation length describing the size of the interfacial region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1040–1046;2001
Progressive morphology development to produce multilayer films and interpenetrating blends by chaotic mixing
Authors: Kwon O. , Zumbrunnen D. A. 
Published: October 2004

AbstractChaotic mixing of immiscible binary components was recently used in a continuous flow process to obtain extruded films with very many internal layers. Where interfacial tension is small, individual layer thicknesses can be only tens of nanometers and many thousands of continuous or broken layers can be formed. Such materials are both novel and potentially important. In this study, multilayer film formation and breakup were investigated systematically by using a batch chaotic mixer to better understand the more industrially relevant continuous flow counterpart. Polystyrene (PS) and low‐density polyethylene (LDPE) were used as a model binary system with appreciable interfacial tension such that comparatively thicker layers and larger breakup bodies were formed and more readily examined. The multilayer film morphology developed progressively as chaotic mixing continued and was thereby amenable to control and optimization with regard to layer thickness and number. Blends with single or dual phase continuity and structured droplet distributions were found to be important derivative morphologies upon layer breakup. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1569–1579, 2001
Degree of crosslinked cotton cellulose with prereacted DMDHEU–AA
Authors: Chen Jui‐Chin , Yao Wei‐Hua , Chen Chien‐Hsin , Chen Cheng‐Chi 
Published: October 2004

AbstractDimethyloldihydroxyethyleneurea (DMDHEU) and acrylic acid (AA) were used to synthesize the dimethyloldihydroxyethyleneurea–acrylic acid product (DMDHEU–AA, mole ratios of DMDHEU/AA = 1/0, 1/1, and 1/2, respectively). Cotton fabrics were treated with the various prereacted DMDHEU–AA products by changing resin concentrations in the bath. We found that the dry crease recovery angle (DCRA) and wet crease recovery angle (WCRA) of the treated fabrics increased with the increase of acrylic acid in the prereacted DMDHEU–AA at the same value of resin concentration in the bath, whereas the tensile strength retention (TSR) showed the inverse tendency. For a given value of number of crosslinks per anhydroglucose unit (CL/AGU), the DCRA and WCRA values of the DMDHEU–AA‐treated fabrics were higher than those for DMDHEU‐treated fabrics. Additionally, agent distribution and the reaction between –COOH of the crosslinking agent and cellulose molecule were also investigated in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1580–1586, 2001
Monitoring water uptake of polyurethanes by in situ fluorescence technique
Authors: Hakala K. , Vatanparast R. , Vuorimaa E. , Lemmetyinen H. 
Published: October 2004

AbstractThe water uptake of three polyurethane adhesives was studied by an in situ fluorescence method applying extrinsic fluorescent probes. The measurements were made in water immersion at 50 and 80°C, and in water vapor at 50°C. An intensity ratio method was applied, in which ratios of the highest and lowest intensity changes in the fluorescence emission bands were used to determine the amount of water sorbed in the polymer films. The ratio method was used to compare the fluorescence data with those obtained by a conventional gravimetric method. Comparable results were obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1593–1599, 2001
Synthesis and properties of PMR type poly(benzimidazopyrrolone‐imide)s
Authors: Li Y. F. , Hu A. J. , Wang X. C. , Gao S. Q. , Yang S. Y. 
Published: October 2004

AbstractPMR type poly(benzimidazopyrrolone‐imide) or poly(pyrrolone‐imide) (PPI) matrix resin was synthesized using the diethyl ester of 4,4′‐(hexafluoroisopropylidene)diphthalic acid (6FDE), 3,3′‐diaminobenzidine, para‐phenylenediamine, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid (NE) in anhydrous ethyl alcohol with N‐methylpyrrolidone. The homogeneous matrix resin solution (40–50% solid) was stable for a storage period of 2 weeks and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbon fiber‐reinforced polymer composites was accomplished at optimal thermal curing conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540°C. Results of MDA experiments indicate that the materials showed > 70–80% retention of the storage modulus at 400°C and glass transition temperatures as high as 440–451°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1600–1608, 2001
Photopolymerization of hyperbranched aliphatic acrylated poly(amide ester). I. Synthesis and properties
Authors: Lin De , Shi Wen‐Fang , Nie Kang‐Ming , Zhang Yu‐Chuan 
Published: October 2004

AbstractThe hyperbranched aliphatic poly(amide ester) (HAPAE) was synthesized based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid prepared by the reaction of succinic anhydride with diethanol amine, as an AB2 monomer (repeating unit), and with 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol, as a core molecule, using acid catalysis. The second generation of the product was characterized by measuring dynamic viscosity, which decreased sharply with the increase in frequency. The product exhibits relative thermal stability as analyzed by thermogravimetry in a nitrogen atmosphere. The glass transition temperature, determined by differential scanning calorimetry, is −27 °C. The molar mass was measured by vapor pressure osmometry. The polydispersity, measured by size exclusion chromatography, is 2.16. Dynamic mechanical thermal analyses were performed to characterize the thermal properties of the ultraviolet‐cured films of the acrylate‐modified HAPAE. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1630–1636, 2001
Photopolymerizaton of hyperbranched aliphatic acrylated poly(amide ester). II. Photopolymerization kinetics
Authors: Lin De , Kou Huiguang , Shi Wen‐Fang , Yuan Hui‐Ya , Chen Yong‐Lie 
Published: October 2004

AbstractA hyperbranched aliphatic poly(amide ester) ending with hydroxyl groups based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid (DKBA) and 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol (TMP) was modified with acryloyl chloride, resulting in a radiation‐curable, hyperbranched acrylated poly(amide ester). This hyperbranched polymer was characterized with respect to ultraviolet cure rate, unsaturation conversion, and mechanical properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1637–1641, 2001
Studies of dielectric characteristics and surface energies of spin‐coated polyimide films
Authors: Qu Wen‐Li , Ko Tze‐Man 
Published: October 2004

AbstractA two‐step method, that is, polyamic acid formation with subsequent curing, was used to synthesize six kinds of polyimides. Dielectric constants and surface energies were investigated to determine the nature of the fluorinated and nonfluorinated polyimides. The dielectric constant decreased from 3.3 (at 100 kHz) for PMDA/ODA to 2.6 (at 100 kHz) for 6FDA/4,4′‐6F when the fluorine content increased from 0 to 30.7 wt %. Simultaneously, the water contact angle increased from 65° for PMDA/ODA to 78° for 6FDA/4,4′‐6F. Experimental results indicated that fluorinated polyimides contained a lower dielectric constant with improved water resistance. The surface energy values obtained from experiments agreed well with Holmes' correlation between surface energy and dielectric constant. The surface energies and dielectric constants were significantly affected by the polymer backbone structures, especially by the fluorination effect. Therefore, by choosing the appropriate monomers, polyimides of low dielectric constants with hydrophobic surfaces could be obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1642–1652, 2001
Synthesis of poly(vinyl acetate)‐graft‐polystyrene and application to preparation of porous membranes
Authors: Park Eun‐Soo , Yoon Jin‐San 
Published: October 2004

AbstractPoly(vinyl acetate)–TEMPO (PVAc–TEMPO) macroinitiators were synthesized by bulk polymerization of vinyl acetate in the presence of benzoyl peroxide (BPO) followed by termination with 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO). Radicals were mainly transferred to the acetoxy methyl groups in PVAc during the polymerization. The PVAc–TEMPO macroinitiators had several TEMPO‐dormant sites and styrene bulk polymerization with the macroinitiators produced poly(vinyl acetate)‐graft‐polystyrene (PVAc‐g‐PS). All the TEMPO‐dormant sites of PVAc–TEMPO macroinitiators participated in the styrene polymerization with almost equal reactivity. Methanolysis of PVAc‐g‐PS broke the PS branches apart from the PVAc backbone chains. Hydrophobic or hydrophilic porous membranes with controlled pore size could be prepared by removing the PVAc domains or the PS domains from the graft copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1658–1667, 2001
Kinetic study of emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol, stabilized with poly(ethylene oxide)–block–polystyrene–block–poly(ethylene oxide) triblock copolymer
Authors: You Xiaorong , Dimonie Victoria L. , Klein Andrew 
Published: October 2004

AbstractThe kinetics of emulsion copolymerization of ethyl methacrylate (EMA)/lauryl methacrylate (LMA) in propylene glycol is very similar to the emulsion copolymerizations of water‐soluble monomers in water because of the high solubility of EMA/LMA in propylene glycol. The initial rate of polymerization depends only on initiator concentration and is not affected by either monomer concentration or stabilizer concentration. The overall rate of polymerization is only slightly dependent on monomer concentration and stabilizer concentration and is independent of initiator concentration. The final particle number density increases with increasing amount of stabilizer and decreases with increasing monomer concentration. The total surface area increases with stabilizer concentration and is not governed by either initiator concentration or monomer concentration. Homogeneous nucleation is the dominant mechanism of particle nucleation, as shown by the kinetic data on seeded polymerization and monomer partition behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1691–1704, 2001
Effect of polymer loading on the electrical and thermodynamic properties in relation to gas chromatographic applications
Authors: El‐Naggar A. Y. , Turky G. M. 
Published: October 2004

AbstractDifferent layers, 5, 10, 15, and 25% (w/W), of the three studied polyethylene glycols (PEGs) having different molecular weights, 600, 4000, and 20,000, were used for coating on chromosorb pink acid washed (P AW). The polarity and selectivity of the prepared packing columns and their thermodynamic parameters were determined via inverse gas chromatography. The effect of polymer‐layer thickness on the polarity was studied dielectrically. The dependence of specific retention volume, enthalpy, and entropy upon the loading of polymer on support were also studied. In all investigated polymers, the loads 5 and 10% deactivate the support surface, resulting in a decrease in its capacitances, which reflects the polarity. The loads 15% PEG20,000 and 25% PEG4000 can elute n‐alcohols and exhibit high efficiency of separation; however, in the case of PEG600, loading has to exceed 25% to be sufficient for eluting n‐alcohols. The lower thickness of the coated polymers was preferred for good separation of saturated hydrocarbons and also for cyclohexane and aromatic hydrocarbons. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1709–1717, 2001
Effect of coupling agents on the mechanical properties of fly ash/polyester particulate composites
Authors: Guhanathan S. , Devi M. Saroja , Murugesan V. 
Published: October 2004

AbstractFly ash (FA)/general purpose unsaturated polyester resin (GPR) particulate composites were made. The effect of the surface treatment of FA with two different silane coupling agents (CAs) on the mechanical properties, such as the tensile, flexural, compressive, and impact strengths and hardness, of FA–GPR composites were studied. The properties of FA–CA–GPR were also compared with that of GPR and CaCO3–GPR. An enhancement in the tensile, flexural, compressive, and impact strengths and a decrease in the tensile and flexural moduli were observed when FA was surface treated with CA. Hardness also increases with CA‐treated FA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1755–1760, 2001
Strengthening blends of poly(lactic acid) and starch with methylenediphenyl diisocyanate
Authors: Wang Hua , Sun Xiuzhi , Seib Paul 
Published: October 2004

AbstractPoly(lactic acid) (PLA) is a biodegradable polymer, but its applications are limited by its high cost. Blending granular starch with PLA reduces the cost, but the blend has poor strength properties. In this study, a 55/45 (w/w) mixture of PLA (weight‐average molecular weight = 120,000 Da) and dried wheat starch was blended thermally in an intensive mixer with or without a low level of methylenediphenyl diisocyanate (MDI). Blends with MDI had enhanced mechanical properties that could be explained by the in situ formation of a block copolymer acting as a compatibilizer. Scanning electron micrographs showed reduced interfacial tension between the two phases. The presence of MDI also enhanced the mechanical properties of the blend at temperatures above the glass‐transition temperature. Water uptakes by the PLA/starch blends with and without MDI did not differ. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1761–1767, 2001
Multivariate statistical analysis of mid‐infrared spectra for the online monitoring of 2‐ethylhexyl acrylate/styrene emulsion copolymerization
Authors: Stavropoulos Y. , Kammona O. , Chatzi E. G. , Kiparissides C. 
Published: October 2004

AbstractThis article describes the application of multivariate statistical process control techniques to a series of mid‐infrared spectra collected online from a styrene/2‐ethylhexyl acrylate emulsion copolymerization process. Principal component analysis of the mid‐infrared spectral data indicated that in situ monitoring of the complex copolymerization process was feasible in the spectral region of interest. It was also observed that projection to latent structures or partial least squares (PLS) could be used for the effective indirect online prediction of individual monomer conversions and copolymer compositions over a substantial range of process operating conditions. A combination of the developed PLS methodology with a mid‐infrared attenuated total reflection probe proved to be an effective tool for the efficient online characterization of polymer quality, thereby overcoming the lack of robust online conversion and composition measuring devices. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1776–1787, 2001