bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional polymers for colloidal applications. I. Structural effects of lipophile‐modified polyacrylates on adsorption and dispersion ability
Authors: Kuo Ping‐Lin , Chang Ta‐Cheng , Lu Li‐Mei 
Published: April 2003

AbstractPolyacrylic acids of four molecular weights are prepared. A series of poly(methylacrylate‐acrylic acid) copolymers with four specific methylacrylate/acrylic acid ratios and molecular weights has been successfully synthesized from the corresponding polyacrylic acids. These polymers and copolymers are used as dispersants for dispersing TiO2 into aqueous phase. Viscosity, sedimentation, and electron microscopy are used to evaluate their dispersion ability. The extent of adsorption and the zeta potential are measured to evaluate their adsorption behaviors on the surface of TiO2. The viscosity, sedimentation, and electron microscopy results are comparable parallel for showing the dispersing ability of a polymer or a copolymer. The polymer (or copolymer), which results in a lower viscosity, shows a slower sedimentation rate and a more homogeneous distribution of particles in microphotographs. The minimum viscosity needed to disperse TiO2 decreases with the decreasing molecular weight of polyacrylic acid. It was found that partial esterification of polyacrylic acid results in a broader range of minimum viscosity. The trend of the amount adsorbed is similar to that of zeta potential. These two results are used to interpret the viscosity curve.
Kinetics of imidization of poly(amic acid) in miscible and immiscible polymer blends
Authors: Makhija S. M. , Pearce E. M. , Kwei T. K. 
Published: April 2003

AbstractBlends of commercial poly(amic acid), LARC‐PAA polymer were prepared with thermoplastic polyimide P84. The blends were shown to be miscible over a certain composition range. Chemical imidization of LARC‐PAA in the blends leads to phase separation. Thermal imidization of LARC PAA in the blends was carried out in the solid state. Miscible compositions of the blend remained miscible after imidization and showed a single glass transition for each blend. Immiscible compositions after imidization remained immiscible and showed two glass transition temperatures in the DSC scans. The kinetics of thermal imidization of PAA to polyimide (PI) in the solid state were studied using FTIR. In the immiscible blend the kinetics remained unaffected while in the miscible state the rate of imidization became faster than that of the pure PAA.
Analysis of thermal curves obtained during radiation curing of polymeric films
Authors: Gozzelino G. , Priola A. , Mantegna M. 
Published: April 2003

AbstractThermal curves were obtained during the UV curing process of a film containing reactive oligomers by monitoring in “real time” the temperature of the film surface by means of a high sensitive thermocouple. The system can be reproduced by a mathematical model that allows one, in welldefined conditions, to obtain the thermal curve of the system when the physical parameters of the materials, the polymerization enthalpy, and the kinetics of the double bond conversion are known. By using the kinetic data obtained through real time FTIR analysis, the model allows one to obtain the theoretical thermal curve of the system. The agreement between this curve and that obtained experimentally was found satisfactory, thus confirming the validity of the model proposed. The possible applications of the method are discussed.
Crosslinking of poly(vinyl chloride) with bismaleic compound. I. Crosslinking mechanism
Authors: Chen Minwei , Zhou Dafei 
Published: April 2003

AbstractCrosslinked poly(vinyl chloride) (PVC) was obtained by using bismaleic compound (BMC). Styrene, as auxiliary crosslinker, can markedly promote the crosslinking course. After having carefully studied the gelling behavior of PVC in crosslinking, and the reactivity of styrene and BMC with PVC, the crosslink mechanism was suggested. The main crosslink reaction is the bridging of bismaleic compound between PVC macroradicals, which were created by thermal degradation of PVC and disproportionation of PVC with initiator radicals and styrene radicals. The first step of crosslink reaction was the BMC grafting on PVC macroradicals. Then styrene copolymerizes with active center bearing on bismaleic compound to propagate graft chain, which make bridging reaction easier to take place. At last, PVC* reacted with another double bond possessed by grafted BMC to form network structure
The introduction of alkyl, ester, carboxylate, amino, hydroxyl, and phosphate functional groups to the surface of polyethylene
Authors: Bentjen Susan B. , Nelson David A. , Tarasevich Barbara J. , Rieke Peter C. 
Published: April 2003

AbstractThe surface of polyethylene was derivatized with ester, carboxylate, amino, hydroxyl, and phosphate functional groups. α, ω bifunctional alkanes, containing on one end a primary amine, were coupled to oxidized polyethylene through an amide linkage. Polyethylene was first oxidized with chromic acid, the carboxylate groups were converted to the acyl chloride with phosphorus pentachloride, and then reacted with a primary amine to give the covalently bound amide. The copposing ends of the bifunctional alkanes were the methyl, tertiary amine, ester, and hydroxyl groups. The ester was converted to the carboxylate by acid cleavage and the hydroxyl group converted to the phosphate by treatment first with phosphorus oxychloride and then aqueous base. Attenuated total reflection FTIR, XPS, and pH‐dependent contact angle wetting were used to characterize the surfaces. The FTIR data were used to confirm the formation of the amide and to detect an undesired carboxylate/ammonium ion complex formed in the presence of trace amounts of water. XPS data were used to confirm expected changes in elemental composition and to provide quantitative estimates of the yields. Oxidation of the polyethylene introduced 5 × 1014 carboxylate groups/cm2 in the 25 Å XPS sampling depth. Of these, up to 98% could be converted to the amide. The advancing contact angle data confirmed the acid/base behavior of the functional groups.
Compression creep of molten low‐density polyethylene
Authors: Aleman J. V. 
Published: April 2003

AbstractViscoelastic parameters of low‐density polyethylene melt (LDPE) in compression creep have been measured. Volume deformation (k%) increases as pressure (P) increases and temperature (T) decreases. Plots of the bulk creep compliance B(t) vs. time (t) may be shifted to provide master curves. As the pressure and the temperature increase, the pressure shift factors (bp and ap) increase almost linearly [activation volumes (ΔV*) varying from 1.0 to 15.0 cm3 mol], while the temperature‐shift factors (bT and aT) decrease. The steady‐state creep compliance (Bs) describes the recoverable storage of elastic energy (Be) and seems to be related to the extrusion die‐swell (Bsc/Bsd). Volume viscosity (ηK) decreases with increasing stress (P) and increasing temperature (T).
Solute migration through polypropylene blend films
Authors: Jenke Dennis R. 
Published: April 2003

AbstractThe migration of several low molecular weight model solutes through a polypropylene/polyolefin blend was examined via a permeation‐cell experimental design. Diffusion coefficients and permeation rates are obtained for the model solutes. The permeation rates exhibit Arrenhius‐type behavior. A bimodal permeation model is proposed wherein the permeation rate is correlated with the linear combination of a solute's Permicor constant and solute/polymer equilibrium interaction constant. The model effectively predicts the behavior of the polymer and solutes studied. The implication of the observed behavior to container compatibility assessment is discussed.
Permeation of binary–liquid mixtures through elastomers
Authors: Vahdat Nader , Taylor Henry , Alsayegh Ali 
Published: April 2003

AbstractPermeation of binary liquid mixtures through two commercially available elastomers were examined. The four systems studied are benzene–cyclohexane/neoprene, toluene–n‐hexane/neoprene, toluene–methanol/nitrile, and toluene–o‐xylene/nitrile. Permeation rate–time curves for several mixture compositions were prepared for each system. In the first three systems, the difference in the plasticizing effect of the two liquids on the membrane was very large. The liquid with the smaller plasticizing effect showed a permeation enhancement and the liquid with the larger plasticizing effect experienced a permeation depression. Toluene–o‐xylene/nitrile represented a system in which the two liquids plasticized the membrane at almost the same rate. This system showed a permeation depression for both liquids.
Studies on curing urethane prepolymers with aniline–formaldehyde resins
Authors: Kozakiewicz Janusz , Orzechowski Andrzej , Raszczuk Alina , Jamróz Michai H. , Dobrowolski Jan Cz. 
Published: April 2003

AbstractCommercial aniline–cresol–formaldehyde resin, two model aniline–formaldehyde and aniline–cresol–formaldehyde resins, and methylenedianiline have been used as curatives for NCO‐terminated urethane prepolymer prepared from polyoxypropylenediol and toluene‐diisocyanate. Based on viscoelastic behavior of the investigated systems and changes in their IR spectra, it has been concluded that phenolic OH groups present in aniline–cresol–formaldehyde resin do not play an important role in the curing process carried out at RT despite earlier suggestions to the contrary. The explanation for specific behavior of systems where urethane prepolymers have been cured with commercial aniline–cresol–formaldehyde resin is presumably the presence of small amount of solvent (benzyl alcohol) in that resin, which may influence the reaction kinetics.
Ablation of poly(2‐hydroxyethyl methacrylate) by 193‐nm excimer laser radiation
Authors: Chirila Traian V. , Van Saarloos Paul P. 
Published: April 2003

AbstractData on the ablation of poly(2‐hydroxyethyl methacrylate) (PHEMA) by 193‐nm radiation pulses, produced by an ArF excimer laser, are presented for the first time and are compared with the data for poly(methyl methacrylate) (PMMA). The ablation rate of PHEMA is lower than that of PMMA and some possible explanations are advanced. The other features of the etch curves are similar and confirm a predicted ablative behavior of the addition polymers susceptible to depolymerization. Geometric aspects of the ablated polymer's surface, and the influence of inhomogeneities in the material, are also presented and discussed.
Polymerization of olefins through heterogeneous catalysis X: Modeling of particle growth and morphology
Authors: Hutchinson R. A. , Chen C. M. , Ray W. H. 
Published: April 2003

AbstractThe development of a detailed model describing particle growth in olefin copolymerization systems is presented. The Multigrain Model considers in detail monomer sorption, mass transfer, and changing porosity within the growing particle, as well as heat and mass transfer across the external film of the particle. The model predicts catalyst performance, including polymerization rates and particle morphology, in different reactor media without parameter adjustment. Internal void fractions are calculated through an examination of the relative growth rates within the growing particle. The model is used to examine the effects of mass transfer limitations, prepolymerization, and nonuniform metal distribution on the particle growth process. Model predictions of morphology show the same trends as observed experimentally.
Plasma modification of cellulose derivatives as biomaterials
Authors: Poncin‐Epaillard Fabienne , Legeay Gilbert , Brosse Jean‐Claude 
Published: April 2003

AbstractA film of cellulose acetate was submitted to a cold plasma of tetrafluoromethane or of sulfur hexafluoride. The interactions of these cold plasmas and cellulose acetate lead to a material whose surface has been modified by fluorination. Comparison of CF4 or SF6 plasma treatment shows that fluorine atoms provided by each kind of plasma induce degradation and grafting of fluorocarbon radicals on the surface. As a consequence, the surface energy decreases and offers the possibility of a better response of plasma‐modified cellulose derivatives used as biomaterials (e.g. hemodialysis membrane).
Study on organosilicon positive resist. III. Organosilicon positive excimer laser resist (OSPR‐2016)
Authors: Sugiyama Hisashi , Mizushima Akiko , Nate Kazuo 
Published: April 2003

AbstractA new alkali‐developable organosilicon positive excimer laser (KrF) resist (OSPR‐2016) has been developed for a bilayer resist system. OSPR‐2016 is composed of poly(p‐hydroxybenzylsilsesquioxane) and methyl cholate‐tris (α‐diazoacetoacetate). The ratio is 72.5 : 27.5 w/w. A sample of 0.5‐μ thick OSPR‐2016 resolved 0.35 μ L&S patterns when exposed to a dose of 320 mJ/cm2 from an excimer laser projection printer (NA = 0.37).
Epoxy resins based on aromatic glycidylamines. V. Shelf life of TGDDM‐based epoxy resins
Authors: Podzimek Š. , Dobáš I. , Kubín M. 
Published: April 2003

AbstractThe effect of aging on resin composition was investigated as a part of a study concerned with the evaluation of epoxies containing N, N, N′, N′‐tetraglycidyl‐4,4′‐diaminodiphenylmethane (TGDDM). Long‐term stability of three different epoxy resins based on TGDDM and their mixtures with 4,4′‐diaminodiphenylsulfone (DDS) was followed at 23 ± 2°C at a relative humidity ranging from 45% to 55%, by means of GPC and HPLC; short‐term stability of the resins was evaluated at 125°C.
Swelling characteristics of polymer membranes in the presence of aromatic hydrocarbon liquids
Authors: Harogoppad S. B. , Aminabhavi T. M. , Balundgi R. H. 
Published: April 2003

AbstractSwelling properties of some engineering polymer membranes in the presence of monocyclic aromatic hydrocarbons have been studied from the solvent immersion experiments. The liquids were chosen with varying methyl and methoxy substitutions to study the effect of substitutions on their transport properties. Diffusion coefficients have been extracted from the swelling results. The concentration dependence of diffusion coefficients has been investigated. Furthermore, the swelling and diffusion results have been used to assess the suitability of the polymer membranes in environments containing aromatic hydrocarbon liquids.
Concentration‐dependent diffusion of dye in reactive dyeing systems
Authors: Lin S. H. 
Published: April 2003

AbstractThe physical model of the reactive dyeing system proposed by Sada et al. is extended in this communication to the case with a conentration‐dependent diffusion coefficient of dye. The present model with an exponential concentration dependence of the diffusion coefficient is shown to predict the observed data better than did the previous one with a constant diffusion coefficient. Effects of the concentration dependence of the diffusion coefficient, dye reaction rate, degree of mixing, and volume ratio of fiber substrate to the dyebath on the rate of fractional fiber fixation and the dye concentration in the dyebath are investigated parametrically. It has been found that the effect of the volume ratio of the fiber substrate to the dyebath on the fractional fiber fixation is not of the same order of magnitude as those of the other three factors.
Preparation and characterization of high molecular weight poly(hydroxy ethers) with unusually high glass transition temperatures
Authors: Silvis H. Craig , White Jerry E. , Crain Steven P. 
Published: April 2003

AbstractA series of novel poly(hydroxy ethers) have been prepared via polymerization of the diglycidyl ethers of bisphenol‐A (4), 4,4 ′‐tribromotetramethylbiphenol (6a), and 4,4 ′‐tetrabromotetramethylbiphenol (6b) with a variety of rigid diols in an effort to systematically modify structural features of the phenoxy repeat unit in order to control the torsional mobility of polymer backbones and produce materials with softening temperatures higher than are typical for the class. The resulting poly(hydroxy ethers) displyed glass transition temperatures ranging from 109 to 242°C. There of the polymers were characterized with respect to tensile and impact properties and were compared to the polymer sythesized from bisphenol‐A (1) and bisphenol‐A diglycidyl ether (4).
Multiobjective dynamic optimization of batch free radical polymerization process catalyzed by mixed initiator systems
Authors: Butala D. N. , Liang W. R. , Choi K. Y. 
Published: April 2003

AbstractThe optimal control policies for batch free radical polymerization of styrene catalyzed by a binary mixture of monofunctional initiators have been determined using a multiobjective dynamic optimization technique. The process objectives considered in the optimization include monomer conversion, polymer molecular weight, initiator residue level, and total reaction time. It is illustrated through model simulations and experiments that the performance of the batch polymerization process can be improved significantly through the use of optimal initiator mixture and polymerization temperature programming. This paper also illustrates how the multiobjection optimization technique can be used effectively to solve complex polymerization reactor optimization problems with detailed reaction models.
Copolyimides using 3‐phenyl tricyclo [6,2,2,02,7] dodeca‐2,11‐ene‐5,6,9,10‐tetracarboxylic dianhydride as a thermosetting functional group: Preparation, characterization, and thermal curing chemistry
Authors: Su Ching‐Yie , Lee Yu‐Der 
Published: April 2003

AbstractCopolyimides were prepared by the reaction of 4,4‐oxydianiline (ODA) with two dianhydrides, namely, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and 3‐phenyl tricyclo [6,2,2,02,7] dodeca‐2,11‐ene‐5,6,9,10‐tetracarboxylic dianhydride (PTDDA). ODA and BTDA first reacted in DMAc solvent, then following the addition of PTDDA, which was used as a thermosetting functional group in the polymer's backbone. Two homopolyimides prepared from the reaction of ODA with BTDA or PTDDA were also synthesized. The properties of homopolyimides such as solubility, thermal properties, and thermal curing mechanism were compared to those of copolyimides. The results showed that the tricyclic structure of the PTDDA unit underwent a reverse Diels‐Alder reaction at near 300°C and it controlled the thermal behaviors of copolyimides.
Organotin polymers. XV. Azeotropy in terpolymerization reactions of tributyltin acrylate or methacrylate with itaconic acid or dimethylitaconate and acrylonitrile
Authors: Mahmoud A. A. , Shaaban A. F. , Azab M. M. , Messiha N. N. 
Published: April 2003

AbstractTernary copolymerization of tri‐n‐butyltin acrylate (TBTA) or methylacrylate (TBTMA) with itaconic acid (IA) or dimethyl itaconate (DMI) and acrylonitrile (AN) were carried out in solution at 70°C in the presence of a free radical initiator. Experimental terpolymerization data agreed well with calculations based on the Alfrey‐Goldfinger equation. Ternary azeotropic compositions for TBTA‐IA‐AN, TBTMA‐IA‐IA, and TBTMA‐DMI‐AN systems were 39.0 : 26.1 : 34.9, 51.7 : 10.5 :37.8, and 00.3 : 66.3 : 33.4 mol %, respectively. Also, “pseudo‐azeotropic” regions were indentified where the deviation between feed and polymer compositions is very small.
Cathodically electrodepositable novel coating system from castor oil
Authors: Rao J. Laxmikanth , Balakrishna R. S. , Shirsalkar M. M. 
Published: April 2003

AbstractA novel polyol synthesised from castor oil by aminolysis and a partially blocked toluene–diisocyanate blocked with N,N′‐diethyl lactamide was used to prepare an urethane. This was used in different weight proportions to modify epoxy amine adduct to give binders suitable for cathodic electrodeposition. The pigmented composition of these binders based on the iron oxide (natural) and titanium dioxide (rutile) gave coatings with improved performance.
Synthesis and structure–property relationships of a new class of rubber‐toughened PMMA
Authors: Laurienzo P. , Malinconico M. , Martuscelli E. , Ragosta G. , Volpe M. G. 
Published: April 2003

AbstractIn the present work, blends between poly(methyl methacrylate) (PMMA) and poly(ethylene‐co‐vinyl acetate) (EVA) rubbers obtained by in situ polymerization of the acrylic monomer in the presence of the rubber have been investigated by linear elastic fracture mechanics (LEFM), by Charpy impact tests, and by scanning electron microscopy (SEM). Particularly, a correlation among molecular weight and composition of the EVA rubbers, phase structure development, and, consequently, mechanical impact properties of the resulting blends has been drawn.
On the deformational characteristics of porous polymeric tubes
Authors: Islam M. A. , Malamusis S. , Mladenov I. 
Published: April 2003

AbstractThe deformational behavior of the porous polymeric tube in the operational period has been studied. The tubes are prepared from a polymeric composition consisting of low‐density polyethylene and vulcanized rubber particles. It is established that during operation the tubes undergo only radial elastic deformation. A threshold pressure is necessary to initiate the radial deformation. At a constant pressure, the radial deformation increases with an increase in the polyethylene content in the tube material. The stress necessary to break the tubes during operation is much lower than the tensile strength.
Plasma polymerization of allylamine/3‐aminopropyltriethoxysilane mixtures: Surface nitrogen control
Authors: Barbarossa Vincenzo , Contarini Salvatore , Zanobi Antonio 
Published: April 2003

AbstractA study has been conducted to determine the effects of gas‐feed composition and RF power on the deposition rate and on the surface nitrogen content of thin films produced by plasma polymerization of allylamine/3‐amino‐propyltriethoxysilane (AA/3‐APTS) mixtures. It has been found that while the deposition rate decreases slightly by increasing the AA content in the mixture, the surface nitrogen content, determined by XPS as N : Si molar ratios, increases up to a value of 8 : 1. Moreover, the nitrogen increase is not linear with the AA concentration and a maximum in the N/Si values is found for AA/APTS ratios close to 3 : 1, at all RF powers. The discussion on the polymerization mechanism for the mixture is based on evaluating and combining the behavior of each component, when plasma‐polymerized alone in similar conditions.
Studies of functionalized polystyrene–poly(2, 6‐diphenyl‐1,4‐phenylene oxide) blends
Authors: Hseih D. T. , Peiffer D. G. 
Published: April 2003

AbstractThe phase behavior of an immiscible binary component blend and its functionalized analogs were studied. The unfunctionalized blends are composed of polystyrene and poly(2,6‐diphenyl‐1,4‐phenylene oxide), whereas the functionalized versions contain a relatively broad range of ionic content, i.e., sodium sulfonate units. Extensive glass transition (Tg) measurements show that these blends are immiscible over a broad ionic content and molecular weight range. This phenomenon, however, does not inhibit these blends from possessing improved mechanical properties since the associating‐type ionic interactions can effectively bridge the two phases. These results are in contrast with blends composed of unfunctionalized but miscible components. In this case, miscibility and immiscibility can be tailored through the precise control of the level of functionalization of one or both components of the blend.