bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfonation of styrene‐grafted poly(vinylidene fluoride) films
Authors: Walsby Nadia , Paronen Mikael , Juhanoja Jyrkki , Sundholm Franciska 
Published: October 2004

AbstractElectron‐beam irradiated and styrene‐grafted poly(vinylidene fluoride) films are sulfonated with chlorosulfonic acid in dichloroethane under various conditions. The impact of the reaction time, the concentration of the sulfonating agent, and the reaction temperature on the properties of the sulfonated film is examined. Sulfonation proceeds via a reaction front mechanism. Sulfonation of surface‐grafted films is incomplete at room temperature. The number of side reactions taking place appears to be linearly dependent on the concentration of the sulfonation solution. Dimensional changes suggest that sulfone crosslinking is significant at higher concentrations. This reduces the ion‐exchange capacity and proton conductivity of the films but increases the resistance to oxidation in a H2O2 solution. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1572–1580, 2001
Synthesis and characterization of novel block copolymer from trans‐4‐hydroxy‐L‐proline and poly(ethylene glycol)
Authors: Lee Ren‐Shen , Yang Jen‐Ming 
Published: October 2004

AbstractA series of novel ABA‐type block copolymers were synthesized by polymerization of trans‐4‐hydroxy‐L‐proline (HyP) in the presence of various molecular weight poly(ethylene glycol)s (PEGs), a bifunctional OH‐terminated PEG using stannous octoate as catalyst. The optimal reaction conditions for the synthesis of the copolymers were obtained with 5 wt % stannous octoate at 140°C under vacuum (20 mmHg) for 24 h. The synthesized copolymers were characterized by IR spectroohotometry, proton nuclear magnetic resonance, differential scanning calorimetry, and Ubbelohde viscometer. The glass transition temperature (Tg) of the copolymers shifted to significantly higher temperature with increasing the number average degree of polymerization and HyP/PEO molar ratio. In contrast, the melting temperature (Tm) decreased with increasing the HyP/PEO molar ratio. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1581–1587, 2001
Characterization of branched polymers by size exclusion chromatography coupled with multiangle light scattering detector. I. Size exclusion chromatography elution behavior of branched polymers
Authors: Podzimek S. , Vlcek T. , Johann C. 
Published: October 2004

AbstractThe elution behavior of branched macromolecules during their separation by size exclusion chromatography (SEC) was studied. The elution behavior of branched polymers was investigated using samples of randomly branched polystyrene and star branched poly(benzyl methacrylate) of different levels of branching by means of a SEC chromatograph coupled with a multiangle light scattering detector. Abnormal SEC elution behavior was found to be typical for highly branched polymers. After a normal elution at small elution volumes the molar mass and root mean square radius of the eluting molecules increased with increasing elution volume. Several SEC experiments were carried out to find explanation for this effect and SEC separation was compared with the separation by thermal field flow fractionation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1588–1594, 2001
Application of DMAEMA‐grafted expanded PTFE films to positively charged ultrafiltration membranes and their electrostatic sieve separation properties
Authors: Yamada Kazunori , Gondo Takeshi , Hirata Mitsuo 
Published: October 2004

AbstractA study was done of the ultrafiltration properties of expanded polytetrafluoroethylene (ePTFE) films with two average pore sizes, 0.5 and 3.0 μm, grafted with 2‐(dimethylamino)ethyl methacrylate (DMAEMA)—grafted 0.5‐ePTFE and grafted 3.0‐ePTFE—using dextran (Dxt) and quaternized dextran (qDxt) in water and in buffer solutions with a pH in the range of 4–10. The water permeability was found to be proportional to the operating pressure below 2.0 kgf/cm2. Grafted 0.5‐ePTFE films apparently had a higher rejection than did the grafted 3.0‐ePTFE films, and the cutoff value for grafted 0.5‐ePTFE films decreased with an increase in the grafted amount. The apparent rejection of Dxt and qDxt increased with a decrease in the pH value, and the apparent rejection of qDxt was higher than that of Dxt when the pH was in the range of 4–8 because of an electrostatically repulsive interaction between positively charged grafted PDMAEMA chains and qDxt molecules. For grafted 0.5‐ePTFE films, 40KDxt was selectively separated from the 40KDxt/250KDxt mixture systems in water and from the 40KDxt/40KqDxt mixture systems at pH 6 using the difference in their apparent rejection; the separation factors in both systems increased with the grafted amount. These results indicate that grafted ePTFE films are applicable to positively charged ultrafiltration membranes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1595–1604, 2001
Influence of extenders on thermal and elastic properties of segmented copolyetheresteraramides
Authors: Niesten M. C. E. J. , Bosch H. , Gaymans R. J. 
Published: October 2004

AbstractCopolyetheresteramides with bisesterdiamide units of a uniform length were synthesized in the current study, and the dynamic mechanical and elastic properties of the copolymers produced were studied. Diols are used to extend the length of uniform bisesterdiamide hard segments. Extenders have a twofold effect: increasing the lamellar thickness of the bisesterdiamide crystals and having the ability to independently adjust the ratio between the hard and soft segment. It was found that polymers containing 1,12‐dodecanediol as an extender possess a multiphase structure. Two glass‐transition temperatures (Tg) were observed along with a very broad melting transition. The Tg at about −70°C was found to originate from the amorphous polyether phase, the Tg at about 140–175°C was attributed to a glassy aramid‐1,12‐dodecanediol phase. The broad melting transition was caused by the presence of the wide variety of lamellar sizes. This multiphase morphology is probably results from the liquid–liquid demixing of an aramid–polyether and from the aramid‐extender phase. Polymers containing 1,12‐dodecanediol and 13 wt % aramid had an improved elasticity compared to similar polymers without an extender. It is thought this is the result of large isolated, spherically shaped domains become less plastically deformed than the crystalline network of thin lamellae. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1605–1613, 2001
Aberrations in confocal spectroscopy of polymeric materials: Erroneous thicknesses and intensities, and loss of resolution
Authors: Michielsen Stephen 
Published: October 2004

AbstractConfocal fluorescence and Raman microscopy are becoming important characterization methods in polymers, especially for blends and films. However, caution must be used in analyzing the data because of the spherical aberration introduced into the illumination and collection of light caused by a mismatch in the indices of refraction of the sample and the design of the microscope objective. In many cases, the measured shape of the region under examination and the measured intensities are rendered invalid because of this aberration. Simultaneously, the axial resolution is degraded because the central light rays and the extreme rays have different focal points. It is shown that the loss of axial resolution can be minimized and the loss in intensity can be either reduced or accounted for. The error in location within the sample and, hence, the shape can be easily corrected. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1662–1669, 2001
Dynamic light‐scattering characterization of the molecular weight distribution of unfractionated polyimide
Authors: Siddiq Mohammad , Wu Chi 
Published: October 2004

AbstractUsing a developed laser light‐scattering (LLS) procedure, we accomplished the characterization of an unfractionated polyimide (UPI) in CHCl3 at 25°C. The Laplace inversion of precisely measured intensity–intensity time correlation function from dynamic LLS leads us first to an estimate of the characteristic line‐width distribution G(Γ), and then to the translational diffusion coefficient distribution G(D). By using a previously established calibration of D (cm2/s) = 3.53 × 10−4 M−0.579, we were able to convert G(D) into a molecular weight distribution. The weight‐average molecular weight Mw, calculated from the molecular weight distribution, agrees well with that directly measured in static LLS. Our results indicate that both the calibration and LLS procedure used in this study are ready to be applied as a routine method for the characterization of the molecular weight distribution of polyimide. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1670–1674, 2001
Kinetics of miniemulsion polymerization of vinyl acetate with nonionic and anionic surfactants
Authors: Wu X. Q. , Schork F. J. 
Published: October 2004

AbstractThe kinetics of miniemulsion polymerization of vinyl acetate, in which nonionic surfactant, Brij‐35 [polyoxyethylene(23) lauryl ether], and hexadecane were used, was investigated. For comparison, experiments were also carried out using an anionic surfactant (sodium lauryl sulfate). The results show that, for all experiments, both distributions for the particle size of the latices and the molecular weight of polymers were unimodal. The effects of surfactant and initiator levels on the particle number and the polymerization rate were studied. For the system using Brij‐35, the power orders for the dependence of particle number on surfactant and initiator concentrations were 1.33 and 0.68, respectively. The polymerization rate was proportional to the 0.38 power of surfactant level and the 0.84 power of initiator concentration. The hydration layer outside the monomer‐swollen particles in the system of nonionic surfactant may exert a retardation effect on the entry of oligomeric radicals into the particles. The result of GPC analysis indicates that the surfactant concentration inversely affects the molecular weight. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1691–1699, 2001
DSC and DMA studies on silane‐grafted and water‐crosslinked LDPE/LLDPE blends
Authors: Shieh Yeong‐Tarng , Chuang Hui‐Chun 
Published: October 2004

AbstractEffects of silane grafting and water crosslinking reactions on crystallizations, melting behaviors, and dynamic mechanical properties of the LDPE/LLDPE blends are investigated using DSC and DMA. From DSC data, cocrystallization of LDPE and LLDPE does not occur, but cocrosslinking of these two polymers is evidenced at the experimental temperature of 100°C, a temperature lower than melting temperatures of both polymers. The water crosslinking reactions of the LLDPE‐rich blends enable development of a new phase having a melting endotherm in between that of LDPE and LLDPE. From the thermal fractionation data, interaction between LDPE and LLDPE is observed, and compatibilization of the blends can be achieved by the crosslinking reactions. From DMA data, the storage moduli of the blends are not found to be consistent with their degrees of crosslinking. The storage moduli of the blends are not simply determined by the degree of crosslinking but determined by very complicated but unclear factors. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1808–1816, 2001
Oxidative copolymers of aniline with o‐toluidine: Their structure and thermal properties
Authors: Huang Mei‐Rong , Li Xin‐Gui , Yang Yu‐Liang , Wang Xue‐Song , Yan Deyue 
Published: October 2004

AbstractChemically oxidative polymerization of aniline and o‐toluidine (OT) with 6 molar ratios was performed using ammonium persulfate as an oxidant in a HCl medium at −18°C. It was observed that the copolymers were not regularly dependent on the monomer ratio for yield and intrinsic viscosity. The resulting copolymers were characterized by Fourier transform IR spectroscopy, 1H‐NMR spectroscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry, and several thermogravimetry methods. The results showed that the actual content of the OT unit in the copolymers was much higher than the feed content of the OT unit. Given the same reaction conditions, o‐toluidine showed a larger tendency toward homopolymerization rather than toward copolymerization with aniline. The copolymers were amorphous and exhibited thermal decomposition temperatures higher than 440°C and a char yield larger than 39 wt % at 900°C in nitrogen. The activation energy of thermal decomposition for the copolymers was 40–244 kJ/mol in nitrogen and 32 kJ/mol in air, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1838–1847, 2001
Study of additive‐epoxy interaction of thermally reworkable underfills
Authors: Wang Lejun , Wong C.P. 
Published: October 2004

AbstractUnderfill is the material used in a flip‐chip device to dramatically enhance its reliability as compared to a nonunderfilled device. Current underfills are mainly epoxy‐based materials that are not reworkable after curing, which is an obstacle in flip‐chip technology developments, where unknown bad die is a concern. Reworkable underfill is the key to address the nonreworkability of the flip‐chip devices. The ultimate goal of this study is to develop epoxy‐based thermally reworkable underfills. Our previous work showed that when incorporated into epoxy matrix, special additives could provide the epoxy formulation with die‐removal capability around solder reflow temperature. The additive‐epoxy interactions were studied and the results show that the additives do not adversely affect the epoxy properties. Moreover, when the additive decomposition temperature is reached, the decomposition of the additive causes a microexplosion within the epoxy matrix. Subsequently, the adhesion of the epoxy matrix is greatly reduced. Among the four additives studied, Additive1 and Additive2 may be used in reworkable underfills that can be reworked around solder reflow temperature, Additive3 cannot be used in underfill because it greatly reduces the shelf life of the underfill, and Additive4 may be used to develop reworkable underfill that withstands multiple reflows. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1868–1880, 2001
Surface modification strategies for multicomponent polymer systems. III: Effect of diblock copolymer‐modified rutile on the morphology and mechanical properties of LLDPE/PVC blends
Authors: Wang Weidong , Liang Hua , Favis Basil D. , Schreiber Henry P. 
Published: October 2004

AbstractRutile pigment was surface‐modified by the adsorption of various diblock copolymers and used as a component in two‐ and three‐component polymer blends involving the incompatible pair of linear, low‐density polyethylene (LLDPE) and poly(vinyl chloride) (PVC). Stress–strain analyses and electron microscopy show that the copolymer tethered to the rutile surface affects both mechanical and morphological properties of the blends. Inverse gas chromatography was used to evaluate dispersion surface energies and acid–base interaction parameters of the various solids. The mechanical and morphological characteristics of the blends can be rationalized by the concepts of acid–base and dispersion–force interaction. Of the copolymer modifiers used, the diblock based on polyisoprene and poly(4‐vinyl pyridine) (PIP‐P4VP) was best suited for use in LLDPE/PVC blends, ostensibly because of strong acid–base interaction between PVC and P4VP and mechanical interlocking between LLDPE and the PIP moiety. The properties of ternary blends were shown to be dependent on the method used for mixing the components. All mixing procedures used here resulted in time‐dependent variations of mechanical properties, suggesting that none gave rise to equilibrium morphology in the compounds. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1891–1901, 2001
Dynamic mechanical analysis study of the curing of phenol‐formaldehyde novolac resins
Authors: Markovic Slobodanka , Dunjic Branko , Zlatanic Alisa , Djonlagic Jasna 
Published: October 2004

AbstractThe curing reaction of typical commercial phenol‐formaldehyde novolac resins with hexamethylentetraamine (HMTA) was followed by dynamic mechanical analysis. The evolution of the rheological parameters, such as storage modulus G′, loss modulus G″, and tanδ (G″/G′), as a function of time, for samples of the phenolic resins on cloth, was recorded. The curing reaction, leading to the formation of a crosslinked structure, is described by a third‐order phenomenological equation. This equation takes into account a self‐acceleration effect, as a consequence not only of the chemical reaction of crosslinking after the gel point but of phase segregation as well. This rheokinetic model of the curing of phenolic novolac resins permits the determination of the numerical values of the kinetic equation constants. The influence of the composition, structure, and physical treatment on the curing kinetics of the novolac resins is evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1902–1913, 2001
Structural characterization of electron‐beam crosslinked thermoplastic elastomeric films from blends of polyethylene and ethylene‐vinyl acetate copolymers
Authors: Chattopadhyay S. , Chaki T. K. , Bhowmick Anil K. 
Published: October 2004

AbstractFilms were prepared from a blend of low‐density polyethylene (LDPE) and ethylene‐vinyl acetate (EVA) containing 45% VA and ditrimethylol propane tetraacrylate (DTMPTA). Electron‐beam initiated crosslinking of these films was carried out over a range of radiation doses (20–500 kGy), concentrations of DTMPTA (1–5 parts by weight), and blend compositions. The IR studies revealed that oxidation and crosslinking dominated up to an irradiation dose of 100 kGy. At higher irradiation doses chain scission and disproportionation predominated among all the competitive processes for the 50:50 blend without DTMPTA. The gel fraction of the films increased with the increase in irradiation dose, DTMPTA level, and EVA content of the blends. X‐ray diffraction and differential scanning calorimetry studies showed that the crystalline portion of the blends was only affected by radiation at higher irradiation doses (≥200 kGy). Scanning electron microscopy studies indicated that in the 50:50 blend the LDPE formed the continuous phase, which was further confirmed by atomic force microscopy and transmission electron microscopy studies. However, a co‐continuous morphology was formed when the EVA content was increased. When DTMPTA was added to the blends (≥3 wt %), the 50:50 blend exhibited a co‐continuous morphology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1936–1950, 2001
Modeling of the sheet‐molding process for poly(methyl methacrylate)
Authors: Zhou Fangbin , Guptam Santosh K. , Ray Ajay K. 
Published: October 2004

AbstractThe sheet‐molding process for the production of poly(methyl methacrylate) (PMMA) involves an isothermal batch reactor followed by polymerization in a mold (the latter is referred to as a “sheet reactor”). The temperature at the outer walls of the mold varies with time. In addition, due to finite rates of heat transfer in the viscous reaction mass, spatial temperature gradients are present inside the mold. Further, the volume of the reaction mass also decreases with polymerization. These several physicochemical phenomena are incorporated into the model developed for this process. It was found that the monomer conversion attains high values of near‐unity in most of the inner region in the mold. This is because of the high temperatures there, since the heat generated due to the exothermicity of the polymerization cannot be removed fast enough. However, the temperature of the mold walls has to be increased in the later stages of polymerization so that the material near the outer edges can also attain high conversions of about 98%. This would give PMMA sheets having excellent mechanical strength. The effects of important operating (decision) variables were studied and it was observed that the heat‐transfer resistance in the mold influences the spatial distribution of the temperature, which, in turn, influences the various properties (e.g., monomer conversion, number‐average molecular weight, and polydispersity index) of the product significantly. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1951–1971, 2001
Reactive extrusion of polycaprolactone compounds containing wood flour and lignin
Authors: Nitz Hansjörg , Semke Hinnerk , Landers Rüdiger , Mülhaupt Rolf 
Published: October 2004

AbstractBiodegradable polycaprolactone (PCL) was melt‐compounded in a Werner & Pfleiderer twin‐screw extruder (ZSK25) together with wood flour (WF) and lignin with maleic anhydride‐grafted polycaprolactone (PCL‐g‐MA) used as a compatibilizer. The grafting of maleic anhydride onto PCL was achieved with reactive extrusion in the presence of 2,5‐dimethyl‐2,5‐di‐(t‐butylperoxy)hexane as an initiator. The graft copolymers were analyzed with size exclusion chromatography and titration. As a function of the initiator and maleic anhydride addition, the grafted maleic anhydride content varied from 1.4 to 3.1 wt %. Compounds compatibilized with PCL‐g‐MA exhibited improved mechanical properties: a compatibilized PCL compound containing 40 wt % WF gave a Young's modulus of 2300 MPa with respect to 400 MPa for neat PCL and a 100% increase in yield stress. The content of WF, lignin, and PCL‐g‐MA was varied systematically to examine stress–strain and impact behavior. Low contents of grafted maleic anhydride and PCL‐g‐MA were required to improve both mechanical properties and interfacial adhesion. Biodegradation was investigated. Lignin addition was found to retard biodegradation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1972–1984, 2001
Study on the redox adsorptive properties of fiber containing iso‐thiourea group toward Au(III)
Authors: Tang Shunqing , Lu Yun , Zeng Hanmin 
Published: October 2004

AbstractFunctional fiber containing iso‐thiourea group was prepared by reactive chloromethylated poly(vinyl acetate)‐graft‐polystyrene–divinylbenzene (PVA‐g‐PS–DVB) being reacted with thiourea. The functional group content of the fiber was 2.90 mmol/g. The chloromethylated PVA‐g‐PS–DVB reacted with sulfur atoms in the thiourea molecules; this made the fiber containing iso‐thiourea group. The results of static adsorption experiments showed that the adsorption amount of the fiber toward Au(III) reached a maximum amount, 1000 mg/g, at pH 1.5. It reduced the adsorbed Au(III) into Au(0), and the maximum reduction percentage was 90% at pH 2.0. The amount of Au(III) adsorbed by the fiber increased with increasing solution temperature but decreased with the increasing ionic strength of the solution. It was proven by electron spectroscopy for chemical analysis that some of the sulfur atoms in the fiber were oxidized into sulfone groups or sulfate ions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1985–1990, 2001
Preparation and characterization of blends of high density polyethylene and poly(ethylene‐co‐1‐octene) elastomer
Authors: Guimarães Maria José O. C. , Coutinho Fernanda M. B. , Rocha Marisa C. G. , Garcia Maria Elizabeth F. 
Published: October 2004

AbstractMechanical, thermal, and morphological properties of blends of high density polyethylene and poly(ethylene‐co‐1‐octene) (PEO) were evaluated. The blends were prepared in a single screw extruder at 230°C and 50 rpm with volume fraction of elastomer varying in the range from 0.05 to 0.8. Factors such as chemical similarity and melt viscosity favor the interdiffusion process of phases, resulting in better interfacial adhesion. A synergistic effect on the strength at break and elongation at break for a particular range of blend composition was observed. Blends with a volume fraction of PEO higher than 5% presented a super tough behavior at room temperature. Thermal analysis showed that there is a certain degree of interaction between high density polyethylene and PEO. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1991–1995, 2001