bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on membrane formation mechanism by the light transmission technique. I
Authors: Hao Ji Hua , Wang Shichang 
Published: November 2002

AbstractNew parameters, light transmission rate and minimum light transmissions, are proposed. These two parameters reflect the characteristics of the membrane‐forming system and the formation process of the membranes by phase inversion. The relationship between the light transmission and the porous structure of the membrane can be explained by the geometrical optics principles. Variation of the two parameters combining Reuvers's phase separation theory provided a convenient analytical method to predict effectively membrane morphologies. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 174–181, 2003
Effect of serum components on styrene/butyl acrylate latex film formation: An in situ examination by ultramicroscopy
Authors: Keslarek Amauri José , Galembeck Fernando 
Published: November 2002

AbstractFilm formation by a surfactant‐stabilized, peroxide‐initiated styrene/butyl acrylate latex was followed in situ by ultramicroscopy. The effects of latex serum components on film formation were observed first by the subjection of the latex to extensive dialysis and then by the separate addition of salt and surfactants. Domains of different particle concentrations were observed in the latex dispersion during liquid evaporation, and their positions were related to those of defects in the dry film. Films obtained with the dialyzed latex showed macroscopic defects, which were not seen in the as‐prepared latex. Partially reconstituted latex (dialyzed, with the later addition of salt but not surfactant) behaved like the as‐prepared latex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 159–167, 2003
Photopolymerizable hyperbranched (meth)acrylated poly(amine ester)
Authors: Wei Huanyu , Kou Huiguang , Shi Wenfang , Nie Kangming , Zhan Yuchuan 
Published: November 2002

AbstractA hyperbranched (meth)acrylated poly(amine ester) (HPAE‐2‐A) was synthesized by the modification of the hydroxyl end groups of the second generation of a hyperbranched poly(amine ester) with acryloyl chloride and methacrylic anhydride. The photopolymerization kinetics were investigated with photo‐differential scanning calorimetry and Fourier transform infrared. The properties of HPAE‐2‐A, including the dynamic viscosity, pendulum hardness, and shrinkage, were also studied in comparison with those of a hyperbranched methacrylated poly(amine ester) (HPAE‐2‐MA) prepared in the laboratory and traditional epoxy acrylate and epoxy methacrylate. HPAE‐2‐A polymerized rapidly under UV irradiation in the presence of a photoinitiator and had a higher final conversion of double bonds. The thermomechanical properties of UV‐cured HPAE‐2‐MA films were compared with those of EB‐cured films measured with a dynamic mechanical thermal analyzer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 168–173, 2003
Preparation and performance of high‐impact polystyrene (HIPS)/nano‐TiO2 nanocomposites
Authors: Zhang Jinzhu , Wang Xin , Lu Lude , Li Dan , Yang Xujie 
Published: November 2002

AbstractHigh‐impact polystyrene (HIPS)/nano‐TiO2 nanocomposites were prepared by surface pretreatment of nano‐TiO2 with special structure dispersing agent (TAS) and master batch manufacturing technology. The results show that when the nano‐TiO2 content is 2%, the notched impact strength, tensile strength, and elastic modulus of HIPS/nano‐TiO2 nanocomposites increased to a maximum. This result indicates that nano‐TiO2 has both toughening and reinforcing effects on HIPS. The heat‐deflection temperature and flame‐retardance of HIPS/nano‐TiO2 nanocomposites are also obviously improved as the nano‐TiO2 content is increased. The nanocomposites manufactured by the two‐step method have better mechanical properties than that made by a one‐step method. HIPS/nano‐TiO2 nanocomposites are also non‐Newtonian and pseudoplastic fluids. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 381–385, 2003
Solvent‐free radiation‐curable polyacrylate pressure‐sensitive adhesive systems
Authors: Czech Z. , Milker R. 
Published: November 2002

AbstractThis article shows radiation‐curable solvent‐free pressure‐sensitive adhesive polyacrylates, their synthesis, chemical modifications, important properties and use after crosslinking with UV‐lamps and UV‐lasers for the production of self‐adhesives tapes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 182–191, 2003
Hydrosoluble copolymers of acrylamide‐(2‐acrylamido‐2‐methylpropanesulfonic acid). Synthesis and characterization by spectroscopy and viscometry
Authors: Rosa Fátima , Bordado João , Casquilho Miguel 
Published: November 2002

AbstractHydrosoluble copolymers containing sulfonic acid groups incorporated into a macromolecule were synthesized. The group of polymers studied was obtained by free radical solution polymerization, using potassium persulfate as an initiator. The copolymerization of the monomers 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) and acrylamide (AA) was carried out at different pH values of the reaction medium of the monomer mix. The copolymers were characterized by proton nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The viscosity behavior of the copolymers in NaCl solution showed a dependency on the pH of the reaction medium, with higher pH leading to lower viscosities. The acidic conditions of this medium affect the initiator decomposition rate, which is a probable cause of the viscosity variation, and the extent of decomposition increases with increasing pH. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 192–198, 2003
Pyrolysis GC‐MS of chlorinated natural rubber
Authors: Yang Dan , Li Si‐Dong , Fu Wei‐Wen , Zhong Jie‐Ping , Jia De‐Min 
Published: November 2002

AbstractHigh‐resolution pyrolysis gas chromatography‐mass spectrometry (HRPyGC‐MS) and Fourier transform infrared spectrometry (FTIR) were used to study the structures of the chlorinated natural rubbers (CNR) prepared by two different processes. The results indicate that the fine structures of CNR prepared from “latex” and “solution” processes are different, whereas their basic structures are similar. The molecule of CNR from the “latex” process contains a few carboxyl and carbonyl groups. The rings on CNR molecular chains should be hexatomic rings. The optimum pyrolytic temperature for CNR is 445°C, with an available range from 386 to 590°C. The characteristic pyrolytic products are cyclohexane homologues. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 199–204, 2003
Environmental factors and kinetics of microbial degradation of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) in an aqueous medium
Authors: Wing Hong Lo , Yu Jian 
Published: November 2002

AbstractEnvironmental factors such as oxygen, temperature, and microbial species may have significant effects on decomposition of biodegradable polymers. A representative biodegradable, thermoplastic polymer, poly(3‐hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), was decomposed in an aqueous medium under controlled laboratory conditions by soil microbes for the intrinsic degradation kinetics and the effects of the environmental factors on polymer biodegradation. The amount of proteins, including the PHBV depolymerases, that attached to the polymer surfaces was quite constant during the period of significant mass loss of the polymer specimens. The microbial polymer degradation followed a zero‐order rate model, so the residual mass fraction of PHBV films declined linearly with time. The mixed aerobic microbial organisms from fertile soil showed a higher activity of polymer degradation than an aerobic PHBV‐producing bacterium and the mixed anaerobes in the same soil. The mixed anaerobic microorganisms from barren soil decomposed the polymer at a slower rate than the anaerobes from fertile soil, and this was attributed to fewer microbial cells in the barren soil instead of the difference in the microbial species. The temperature effect on PHBV degradation can be described with an Arrhenius equation, and the activation energy is around 16 kcal/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 205–213, 2003
Crystalline morphology at the interface between polyethylene‐grafted glass and polyethylene
Authors: Duchet Jannick , Gérard Jean‐François , Chapel Jean‐Paul , Chabert Bernard , Brisson Josee 
Published: November 2002

AbstractAdhesion measurements performed on a polyethylene (PE)‐grafted‐glass interface showed that the structure of the PE free chains (matrix) was an important parameter. The fracture energy was higher for interfaces prepared from a linear matrix, such as high‐density polyethylene (HDPE), than for those from a branched PE [low‐density polyethylene (LDPE)]. Therefore, the microstructure of the grafted PE/PE matrix interface or interphase was investigated as a function of the molar masses of the connectors and the structure (linear or branched) of the free PE matrix chains. As the grafted chains were linear, a cocrystalline structure with free chains of the HDPE matrix was generated. PE connecting chains led to a low capacity for cocrystallization with LDPE. Cocrystallization was studied with blends based on functionalized PE chains and PE matrices. These blends were assumed to be miscible, as substantiated by a single differential scanning calorimetry (DSC) peak. The DSC analyses were confirmed by wide‐angle X‐ray scattering, which revealed a crystalline orientation of the chains in the interphase, that is, in the vicinity of the glass surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 214–229, 2003
Synthesis and characterization of acrylic acid‐grafted hydrocarbon and fluorocarbon polymers with the simultaneous or mutual grafting technique
Authors: Horsfall J. A. , Lovell K. V. 
Published: November 2002

AbstractRadiation‐induced graft copolymerization has been used extensively to modify polymers with acrylic acid to impart some properties of the monomer but still maintain the strength and stability of the polymer chain. This article describes the process of the simultaneous graft copolymerization reaction for the modification of hydrocarbon‐ and fluorine‐containing polymers to produce hydrophilic membranes. The effects of the conditions of grafting, such as the radiation dose rate, the total dose, and the monomer concentration on the resulting graft copolymers are discussed in detail. The characterization of the grafted membranes is described in terms of their composition, ion‐exchange capacity, equilibrium water content, and electrolytic resistivity. It has been shown that some of these properties can be predicted from the degree of grafting. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 230–243, 2003
Preparation of uniform hollow polystyrene particles with large voids by a glass‐membrane emulsification technique and a subsequent suspension polymerization
Authors: Ma Guang‐Hui , Chen Ai‐Yi , Su Zhi‐Guo , Omi Shinzo 
Published: November 2002

AbstractHollow polymer particles with large voids were prepared with styrene (St) as the main component and in the presence of a small amount of N,N′‐dimethylaminoethyl methacrylate (DMAEMA) via a glass‐membrane emulsification technique and a subsequent suspension polymerization. A mixture of the monomer, hexadecane (HD), and N,N′‐azobis(2,4‐dimethylvaleronitrile) as an initiator was used as a dispersed phase (oil phase). By the careful pushing of the dispersed phase through the pores of the glass membrane into the aqueous phase, an emulsion of fairly monodisperse monomer droplets was formed. Then, the polymerization was performed by temperature being elevated to 70°C. The aqueous phase (continuous phase) contained poly(N‐vinyl pyrrolidone) as a stabilizer, sodium lauryl sulfate as a surfactant, Na2SO4 as an electrolyte, and sodium nitrite (NaNO2) as a water‐soluble inhibitor. Results related to the effects of the HD content, DMAEMA, and the composition of the comonomer, including the crosslinker and flexible segment, on the features of the hollow particles were investigated. When the content of DMAEMA was higher than 1.0 wt % based on the total monomer, small, secondary particles were generated in the aqueous phase, but the generation was effectively prevented when DMAEMA was limited to 0.5 wt %. Hollow particles, with an average diameter of around 7 μm, were obtained with an St–DMAEMA system. The void size of the hollow particles was controlled by the HD content. When the HD content was lower (<25 wt % based on the oil phase), unbroken hollow particles were easily obtained. However, they tended to break into halves after drying when the HD content was increased to 50 wt %. A soft segment, lauryl acrylate, and a crosslinker, ethylene glycol dimethacrylate, were added to overcome this problem. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 244–251, 2003
Theoretical and experimental investigation of the swelling behavior of sodium polyacrylate superabsorbent particles
Authors: Sohn Ohgun , Kim Dukjoon 
Published: November 2002

AbstractSodium polyacrylate superabsorbent polymers were prepared in particle forms by the inverse suspension technique. The surfactant concentration effect on the polymer particle size was analyzed with molecular sieves and an optical microscope. Water absorption and desorption characteristics were analyzed by the gravimetric method. The equilibrium water uptake in sodium polyacrylate particles was strongly dependent on both the salt concentration of the aqueous media and the crosslinking density of the polymers. The polymer crosslinking density was determined from the measurement of Young's modulus and the polymer–solvent interaction parameter from the equilibrium swelling experiment. The degree of inonization was predicted from experimental measurements, and theoretical analysis was performed on the effects of the salt concentration and polymer crosslinking density on the equilibrium water swelling ratio. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 252–257, 2003
Interfacial properties of polycarbonate/liquid‐crystal polymer and polystyrene/high‐impact polystyrene polymer pairs under shear deformation
Authors: Lam Y. C. , Yue C. Y. , Yang Y. X. , Tam K. C. , Hu X. 
Published: November 2002

AbstractWe developed an energy model derived from the first principle for multilayer configurations to enhance our understanding of the interfacial property between two polymers under shear deformation. We carried out specific experiments satisfying the boundary and loading conditions of the model to obtain the energy dissipation factor (β), which characterized and quantified the interfacial property. Two polymer pairs, the miscible system polystyrene (PS)/high‐impact polystyrene (HIPS) and the immiscible system polycarbonate (PC)/liquid‐crystal polymer (LCP), were investigated. As expected, β was zero for PS/HIPS, reflecting the strong interaction at the PS/HIPS interface. For PC/LCP, the value of β could be significant, and its behavior was complex; it reflected the thermal sensitivity and thermal history effect of the PC/LCP interface. A positive value of β also indicated the possibility of slip at the interface and provided an explanation for the negative deviation from the rule of mixture. This complex behavior of the interface was attributed to the changes in the phases and microstructure of LCPs and, therefore, the LCP/PC interface as thermal cycling was carried out in the melting/nematic range of LCPs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 258–269, 2003
Synthesis of water‐soluble thermosensitive polymers having phosphonium groups from methacryloyloxyethyl trialkyl phosphonium chlorides–N‐isopropylacrylamide copolymers and their functions
Authors: Nonaka Takamasa , Hua Li , Ogata Tomonari , Kurihara Seiji 
Published: November 2002

AbstractWater‐soluble thermosensitive polymers having phosphonium groups were synthesized by the copolymerization of N‐isopropylacrylamide (NIPAAm) with methacryloyloxyethyl trialkyl phosphonium chlorides (METRs) having varying alkyl lengths. The relative viscosities of the copolymer solutions increased with increasing content of phosphonium groups in the copolymers and decreased with increasing chain length of alkyl chains in the phosphonium groups. However, the copolymers of METR with octyl groups in phosphonium groups (METO) and NIPAAm became water insoluble with increasing contents of METO moieties in the copolymers. The transmittance at 660 nm of the copolymer solutions above the lower critical solution temperature (LCST) decreased gradually with increasing temperature and decreased with increasing chain length of alkyl chains in the phosphonium groups. The transmittance at 660 nm of the copolymer solutions above the LCST was greatly affected by the addition of neutral salts such as KCl. The copolymers of METR with ethyl groups in phosphonium groups and NIPAAm and those of METR with butyl groups in phosphonium groups and NIPAAm had high flocculating abilities against bacterial suspensions. The METO–NIPAAm copolymer was found to have a high antibacterial activity. The flocculating ability and the antibacterial activity of the copolymers were affected by not only the content of phosphonium groups but also the alkyl chain length in the phosphonium groups in the copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 386–393, 2003
Gas‐phase polymerization of butadiene. Data acquisition using minireactor technology and particle modeling
Authors: Bartke M. , Wartmann A. , Reichert K.‐H. 
Published: November 2002

AbstractMinireactor technology has been used for kinetic studies on polymerization kinetics, phase equilibrium, and mass transfer on a very small scale. There is a nonlinear influence of temperature and pressure on the polymerization rate. The phase equilibrium can be described by a Flory–Huggins approach, with a temperature‐dependent interaction parameter. The diffusion coefficient seems to be slightly pressure dependent, and the temperature dependence can be described with an Arrhenius equation. A simple formal kinetic scheme with formation of active sites, chain propagation, chain transfer to cocatalyst, and deactivation of active sites has been applied. This kinetic scheme was implemented in two different models; they are, a particle model taking into account mass transfer and a simple chemical model with no mass transfer. In principle, both models describe the experimental results for rate and molecular weight distribution equally well, with rate constants of the same magnitude. Molecular weight distributions calculated by the chemical model are narrower. However, the chemical model gives no explanation for the experimental observed rate dependence on catalyst particle size. With increasing catalyst activity, the differences between both models become more significant and the particle model becomes more and more important. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 270–279, 2003
Preparation of heat‐resistant gradient‐index polymer optical fiber rods based on poly(N‐isopropylmaleimide‐co‐methyl methacrylate)
Authors: Wang Dong‐Jun , Gu Chen‐Bin , Chen Peng‐Lei , Liu Shi‐Xiong , Zhen Zhen , Zhang Jian‐Cheng , Liu Xin‐Hou 
Published: November 2002

AbstractUsing the interfacial gel polymerization method, a heat‐resistant gradient‐index polymer optical fiber (GI POF) was developed based on the copolymer of methyl methacrylate (MMA) and N‐isopropylmaleimide (IPMI) as the matrix material and bromobenzene (BB) as dopant. The gradient distribution of IPMI in the GI POF rod was determined by element analysis. IPMI had great advantage in improving glass transition temperature (Tg) and forming a gradient‐index profile. There was a significant enhancement in the heat‐resistant property in comparison with a conventional GI POF rod. The combination of high thermal stability and easy fabrication makes the novel BB–IPMI–MMA system very suitable for heat‐resistant GI POF. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 280–283, 2003
Influence of different polyesters and their molecular weight on the textural and electrooptical behavior of polymer‐dispersed liquid crystals
Authors: Kundu P. P. , Verma G. , Raina K. K. 
Published: November 2002

AbstractThe textural and electrooptical behavior of a nematic liquid crystal (LC) dispersed in a flexible and rigid polyester was studied. The dispersion of LC in the polymer matrix and light transmission through the polymer‐dispersed liquid crystal (PDLC) is governed by the nature of the polymer, its molecular weight, and the applied voltage. It was observed that the transmission of light and the dispersion of LC maximizes their respective values at the minimum molecular weight irrespective of the nature of the polymer and at the maximum voltage. The reason is the predominance of chain alignment over entanglement at the minimum molecular weight. As molecular weight increases, the transmission of light as well as the dispersion of LC in the polymer may increase or decrease depending on the predominance of chain entanglement or chain alignment. The alignment of LC droplets in the direction of the applied voltage is increased by an increase in the applied voltage, causing enhancement of the light transmission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 284–289, 2003
Graft polymerization of vinyl acetate onto silica
Authors: Nguyen Van , Yoshida Wayne , Cohen Yoram 
Published: November 2002

AbstractThe free‐radical graft polymerization of vinyl acetate onto nonporous silica particles was studied experimentally. The grafting procedure consisted of surface activation with vinyltrimethoxysilane, followed by free‐radical graft polymerization of vinyl acetate in ethyl acetate with 2,2′‐azobis(2,4‐dimethylpentanenitrile) initiator. Initial monomer concentration was varied from 10 to 40% by volume and the reaction was spanned from 50 to 70°C. The resulting grafted polymer, which was stable over a wide range of pH levels, consisted of polymer chains that are terminally and covalently bonded to the silica substrate. The experimental polymerization rate order, with respect to monomer concentration, ranged from 1.61 to 2.00, consistent with the kinetic order for the high polymerization regime. The corresponding rate order for polymer grafting varied from 1.24 to 1.43. The polymer graft yield increased with both initial monomer concentration and reaction temperature, and the polymer‐grafted surface became more hydrophobic with increasing polymer graft yield. The present study suggests that a denser grafted polymer phase of shorter chains was created upon increasing temperature. On the other hand, both polymer chain length and polymer graft density increased with initial monomer concentration. Atomic force microscopy–determined topology of the polymer‐grafted surface revealed a distribution of surface clusters and surface elevations consistent with the expected broad molecular‐weight distribution for free‐radical polymerization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 300–310, 2003