bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the vibrational damping loss factor and viscoelastic properties of ethylene–propylene rubbers reinforced with micro‐scale fillers
Authors: Kwak G. H. , Inoue K. , Tominaga Y. , Asai S. , Sumita M. 
Published: October 2004

AbstractThe influence of microscale fillers on ethylene–propylene rubbers (EPR) was examined with respect to their vibrational damping capacity and viscoelastic properties. The vibrational damping and dynamic mechanical properties of reinforced EPR were studied in systematic and comparative ways that reinforced the evidence of a direct relation between the vibrational damping loss factor and its mechanical damping loss factor. In this study, the sensitivity of the vibrational damping loss factor of reinforced EPR was quantified with respect to the variation in thickness, filler type, and filler content. Dynamic mechanical relaxation behaviors were also analyzed. The viscoelastic properties in terms of the storage modulus, loss modulus, mechanical damping loss factor, and frequency dependence of molecular relaxation showed interesting results with the filler types and compositions that had good correspondence with the vibrational damping behaviors. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3058–3066, 2001
Dimethylammonium dimethyldithiocarbamate‐accelerated sulfur vulcanization. I. Thermal stability and reactions with curatives
Authors: Shumane M. , Gradwell M. H. S. , Mcgill W. J. 
Published: October 2004

AbstractTo investigate its thermal stability and reactivity towards other accelerators dimethylammonium dimethyldithiocarbamate ((dma)dmtc) was heated at programmed heating rates in sealed and open pans in a differential scanning calorimeter and on a thermobalance. (Dma)dmtc was heated on its own, in rubber compounds and in mixes with tetramethylthiuram disulfide, zinc dimethyldithiocarbamate, and ZnO. In open systems (dma)dmtc readily sublimes at temperatures well below its melting point, and it is almost as rapidly lost when compounded on its own with rubber. No decomposition is observed at vulcanization temperatures and (dma)dmtc is unreactive towards tetramethylthiuram disulfide and zinc dimethyldithiocarbamate. Moisture does not promote its decomposition. Reaction with ZnO to give zinc dimethyldithiocarbamate is restricted to the surface of ZnO particles. (Dma)dmtc is soluble in water in which it dissociates. It must be concluded that when its is included in formulations, (dma)dmtc, per se, would act as a vulcanization accelerator; it does not decompose to dimethyldithiocarbamic acid and dimethylamine, both of which are known accelerators. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3067–3073, 2001
Barium chloride crosslinked carboxymethyl guar gum beads for gastrointestinal drug delivery
Authors: Thimma Reddy T. , Tammishetti Shekharam 
Published: October 2004

AbstractA mild method for microencapsulation of sensitive drugs, such as proteins, employing a suitably derivatized carboxymethyl guar gum (CMGG) and multivalent metal ions like Ca++ and Ba++ is reported. Initially, guar gum is derivatized with carboxymethyl groups so that it forms durable, self‐standing microbeads when its solution is dropped into CaCl2 or BaCl2 solutions. The swelling data of Ca++ and Ba++ crosslinked beads suggest that Ba++ crosslinks CMGG much more efficiently than Ca++. The drug loading efficiency of these Ba++/CMGG beads, as a function of concentration of both metal ion as well as drug, was then determined using Bovine Serum Albumin as a model drug. The ability of these beads to protect the drug from the acidic environment of the stomach was investigated. It was found that a very little amount of the drug is released from the beads when they are suspended in NaCl–HCl buffer of pH 1.2 for 6 h. The beads were also shown to release almost the entire encapsulated drug when exposed to TRIS–HCl buffer of pH 7.4. Thus, the results indicate that Ba++ crosslinked carboxymethyl guar gum beads can be used for gastrointestinal drug delivery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3084–3090, 2001
Low‐energy electron beam‐induced cationic polymerization with onium salts
Authors: Boey F. Y. C. , Chia N. K. , Rath S. K. , Abadie M. J. M. 
Published: October 2004

AbstractDemand for higher polymer performance with very short cure times has resulted in the development of low energy electron beam processes. This article presents the results of such a process for curing two epoxy systems, namely 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate and di‐glycidyl ether of bisphenol A (DGEBA), using the cationic photoinitiator salts, triarylsulfonium hexafluoroantimonate, and diaryliodonium hexafluoroantimonate, respectively. Glass transition temperature measurements were done using a modulated DSC method while the degree of conversion was measured using FTIR spectroscopy. Results indicate that for both epoxy systems a relatively low dosage of not more than 5 Mrad was sufficient to achieve up to 60% conversion, with up to 80% conversion achievable using 30 Mrad. The diaryliodonium salt appeared to be more effective than the sulphonium salt in the above study. The effect of varying photoinitiator concentration and the resulting glass transition temperature has been studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3099–3108, 2001
Structure and properties of semiinterpenetrating polymer networks based on polyurethane and nitrochitosan
Authors: Liu Haiqing , Zhang Lina 
Published: October 2004

AbstractTwo semiinterpenetrating polymer networks (semi‐IPNs) based on trihydroxyl methylpropane–polyurethane (T‐PU) or castor oil–polyurethane (C‐PU) were prepared by curing the mixed solution of the polyurethane prepolymer and nitrochitosan (NCH). During the curing process, crosslinking and grafting reaction between the molecules of the PU prepolymer and NCH occurred, because of the high reactivity of remaining hydroxyl groups in the NCH with NCO groups of PU. The structure of the original semi‐IPN sheets and the sheets treated with acetone were studied by infrared, 13C‐NMR, scanning electron microscopy, and dynamic mechanical analysis, showing interpenetration of NCH molecules into the PU networks. When nitrochitosan content (CNCH) was lower than 10 wt %, the semi‐IPN sheets T‐PU and C‐PU had higher density and tensile strength (σb) than the systems with CNCH more than 20%. The trihydroxymethyl propane‐based PU reacted more readily with nitrochitosan to form the semi‐IPNs than castor oil‐based PU. The semi‐IPN coatings T‐PU and C‐PU were used to coat cellophane, resulting in intimate interfacial bonding. The mechanical strength and water resistivity of the cellophane coated with T‐PU coating were improved remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3109–3117, 2001
Synthesis and characterization of ion‐conducting polymer systems based on EPDM blends
Authors: Bashir H. , Linares A. , Acosta J. L. 
Published: October 2004

AbstractWe report on the preparation and characterization of new polymeric ionomers based on EPDM with a high norbornene content. The sulfonation level is determined by means of X‐ray photoelectron spectroscopy and the microstructural characterization is obtained both through differential scanning calorimetry and dynamo‐mechanic analysis. In addition, the effects of certain plasticizers and polymers on the microstructure of these materials were studied, as well as their conducting properties, with special attention to this latter type of behavior, in view of the interest aroused by these materials as membranes in polymer fuel cells. From the obtained results, some of the synthesized membranes can be used for fuel cells because their high conductivity (≥10‐2 S/cm) and their good dimensional stability (any shrinkage observed). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3133–3141, 2001
Arylenecyclosiloxane–dimethylsiloxane copolymers
Authors: Mukbaniani O. , Koiava N. , Karchkhadze M. , Tkeshelashvili R. , Shengelia M. , Khananashvili L. 
Published: October 2004

AbstractThe heterofunctional condensation reaction of 1,4‐bis(phenyldichlorosilyl)benzene with dihydroxydiphenylsilane at a 1:4 ratio of initial compounds in the presence of pyridine was investigated and tetrakis(hydroxydiphenylsiloxy)‐1,4‐bis(phenylsilyl)benzene was obtained. The heterofunctional condensation of the tetrakis(hydroxydiphenylsiloxy)‐1,4‐bis(phenylsilyl)benzene with organotrichlorosilanes at a 1:2 ratio of initial compounds in the presence of pyridine produced dichloro‐containing arylenecyclosiloxanes. The dichloro‐containing arylenecyclosiloxanes were obtained in one stage by successive heterofunctional condensation of 1,4‐bis(dichlorophenylsilyl)benzene with dihydroxydiphenylsilane and organotrichlorosilanes in a 1:4:2 ratio in the presence of pyridine. It was established that the yields of dichloro‐containing products were lower. Hydrolysis of dichloroarylenecyclosiloxanes in a neutral condition produced corresponding dihydroxy compounds. Heterofunctional polycondensation of dicloro(dihydroxy)arylenecyclosiloxanes with α,ω‐dihydroxy(bisdimethylamino)dimethylsiloxanes was used to obtain arylenecyclosiloxane‐dimethylsiloxane copolymers. Thermogravimetric, thermomechanical, and roentgenographic investigations of the synthesized copolymers were carried out. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3142–3148, 2001
Studies on the kinetics of orientation and crystallization of nylon‐66 during high‐speed melt spinning
Authors: Wang Huaping , Wang Biao , Hu Xuechao 
Published: October 2004

AbstractA new way of applying on‐line experimental data and basic theory to study the mechanism of orientation of a high‐speed melt spinning process is described. The relationship of birefringence and stress for Nylon‐66 was developed to understand the phenomena in the spinning line. The value of birefringence along the spinning line was calculated by various models to predict the orientation change. By comparison of the model prediction and on‐line experimental birefringence, a suitable mechanical model to simulate the change of the profiles along the spinning line was chosen, and the structural development mechanism is discussed. The results show that the orientation mechanism of high‐speed melt spinning of Nylon‐66 is determined by deformation and deformation rate along the spinning line. For Nylon‐66, molecular and crystal orientations develop independently and are controlled by the rotation of crystals and chain segments in the deformation field. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3157–3163, 2001
Preparation and characterization of polyamide‐6 with three‐branched chains
Authors: Dai Lixing , Huang Nanxun , Tang Zhilian , Hungenberg Klaus‐Dieter 
Published: October 2004

AbstractWith trimesinic acid as a molecular weight regulator, the hydrolytic polymerization of ϵ‐caprolactam was carried out, and nylon‐6 or polyamide‐6 with three‐branched chains was obtained. Through a systematic study of the effects of conditions such as the reaction time and concentration of trimesinic acid on the polymerization, we found that the conversion of caprolactam was almost insensitive to the initial concentrations of the regulators, but the relative viscosity of the polymer decreased with increasing trimesinic acid. Characterization investigations showed that differential scanning calorimetry curves changed from a single peak for normal nylon‐6 to one main peak and one shoulder or one small peak for the branched polymer; the melting point of the star‐shaped nylon‐6 decreased with an increasing amount of trimesinic acid, whereas its crystallization temperature was higher than that of linear‐chain nylon‐6. A wide‐angle X‐ray diffraction study indicated that the crystal structure of the star‐shaped nylon‐6 still belonged to the α form, and the crystallizability of the branched polymer with an elevated amount of trimesinic acid during polymerization did not seem to be weakened; the characteristic absorption of infrared spectra provided indirect evidence for the existence of branched chains in the polymer. Moreover, the mechanical properties of star‐shaped nylon‐6 and linear‐chain nylon‐6 were compared. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3184–3193, 2001
Study on the preparation and properties of styrene–butyl acrylate–silicone copolymer latices
Authors: Kan Cheng You , Liu De Shan , Kong Xiang Zheng , Zhu Xiao Li 
Published: October 2004

AbstractCopolymer latices of styrene–butyl acrylate–silicone were prepared using a semicontinuous addition process and batch and monomer emulsion addition processes. The results showed that a stable latex with narrow particle size dispersion and a high monomer conversion can be obtained only by the semicontinuous addition process. The simultaneous free‐radical and ionic copolymerization mechanisms were discussed. 3‐Methacryloyloxypropyl trimethoxysilane in this work was used as a coupling agent to form a chemical bond between vinyl polymer and polysiloxane. It was found that the copolymerization reaction and the properties of latex and latex film were obviously influenced by silicone content. When the silicone content was less than 25 wt %, copolymerization proceeded readily and a stable latex could be prepared. With increasing silicone content, monomer conversion, latex stability, film hardness, and tensile strength decreased, whereas the water resistance and impact strength increased. Results of Soxhlet extraction, silicon analysis, and dynamic mechanical properties of latex polymer confirmed the occurrence of copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3194–3200, 2001
Melt spinning of metallocene catalyzed polypropylenes. II. As‐spun filament structure and properties
Authors: Bond Eric Bryan , Spruiell Joseph E. 
Published: October 2004

AbstractThe melt spinning of metallocene catalyzed isotactic polypropylene (miPP) resins was investigated. The as‐spun filament properties from six miPP resins were studied with melt flow rates (MFR) between 10 and 100, and a Ziegler–Natta catalyzed isotactic polypropylene (zniPP) resin with a MFR of 35 was studied for a comparison. Generally, as the molecular weight increased the filament density increased, the birefringence decreased, the tensile strength decreased, and the elongation to break increased. As the spinning speed increased, the density, birefringence, tensile strength, and crystalline and noncrystalline orientation functions generally increased. However, the low MFR miPP and the zniPP resin had decreases in the birefringence and tensile strength with an increase of the spinning speed. The miPP resins were found to have breaking tensile strengths up to 50% higher than the zniPP resin at similar spinning speeds. The observed fiber properties were explained based on the nature and orientation of noncrystalline portions of the fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3237–3247, 2001
Synthesis of polyferrocenyldimethylsilane through ring‐open polymerization and its electrochemical properties in different mediums
Authors: Wang L. , Ye C. Y. , Zhang P. Y. , Pan J. , Feng Linxian , Wang S. F. , Peng T. Z. 
Published: October 2004

AbstractPolyferrocenyldimethylsilanes with different molecular weights were prepared via thermal ring‐opening polymerization of the corresponding strained, silicon‐bridged ferrocenophanes. The electrochemical behavior of the resultant polymers in different media were investigated by cyclic voltammetry. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3258–3261, 2001
Mechanism of fire retardancy of polyurethanes using ammonium polyphosphate
Authors: Duquesne Sophie , Le Bras Michel , Bourbigot Serge , Delobel René , Camino Giovanni , Eling Berend , Lindsay Chris , Roels Toon , Vezin Hervé 
Published: October 2004

AbstractIn this work, we studied the mechanism of the fire retardancy of ammonium polyphosphate (APP) in polyurethane (PU). Indeed, according to the limiting oxygen index test, the efficiency of APP in PU coating was proven. On the one hand, thermogravimetric analyses showed that the addition of APP to PU accelerates the decomposition of the matrix but leads to an increase in the amount of high‐temperature residue, under an oxidative or inert atmosphere. This stabilized residue acts as a protective thermal barrier during the intumescence–fire retardancy process. On the other hand, spectroscopic analysis of the charring materials using infrared spectroscopy, MAS NMR of the solid state, and ESR enables better understanding of the carbonization process and, consequently, of the intumescence phenomenon. It has been shown that the char resulting from PU consists of an aromatic carbonaceous structure which condenses and oxidizes at high temperature. In the presence of APP, a reaction between the additive and the polymer occurs, which leads to the formation of a phosphocarbonaceous polyaromatic structure. Moreover, this char is strongly paramagnetic. The presence of large radical species, such as a polyaromatic macromolecule trapping free radicals, was demonstrated. Both of these characteristics help to explain the fire‐retardant performance of PU/APP. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3262–3274, 2001
Temperature and crystallinity profiles generated in a polycaprolactone/starch blend under different cooling conditions
Authors: Ruseckaite R. A. , Stefani P. M. , Cyras V. P. , Kenny J. M. , Vázquez A. 
Published: October 2004

AbstractThis work concerns the numerical simulation of the temperature profiles and the degree of crystallinity through the thickness of a part made from a commercial biodegradable material based on caprolactone and starch (Mater‐Bi Z), as a function of the cooling conditions from the melt. The crystallization kinetics during cooling conditions was evaluated experimentally by calorimetry and the Kamal–Chu equation was used to describe the degree of crystallinity developed during constant cooling rate experiments. This equation coupled with the thermal energy equation, through a heat source term, described the heat generated during crystallization of the polymer. The numerical solution of the system of differential equations was obtained using an implicit finite‐difference method. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3275–3283, 2001
Modeling of degradation of unstabilized and HALS‐stabilized LDPE films under thermo‐oxidation and natural weathering conditions
Authors: Kaci M. , Sadoun T. , Moussaceb K. , Akroune N. 
Published: October 2004

AbstractMathematical models are proposed to predict degradation of unstabilized low density polyethylene (LDPE) films and those stabilized with hindered amine light stabilizers (HALS) under both thermo‐oxidation at 90°C and natural weathering conditions. The degradation was measured by change in percent elongation at break (ϵr) with time. The mathematical approach developed was multiple linear regression analysis (MLRA). The reliability of the selected models was analysed using four statistical criteria, residual variance, coefficient of determination (r2), Student test and Fisher‐Snedecor test. The linear systems that resulted from the MLRA were resolved by the Cholesky method. The results obtained indicated that the polynomial models developed to predict elongation at break were reliable for both unstabilized and HALS‐stabilized samples under thermo‐oxidation at 90°C and natural weathering conditions. This was also confirmed by the comparison of the half‐life time (HLT) values predicted from the models with those observed experimentally. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3284–3292, 2001
In situ compatibilized SAN/LCP blends through reactive copolymers
Authors: Huang Jieh‐Ming , You Min‐Feng , Chang Feng‐Chih 
Published: October 2004

AbstractStyrene–acrylonitrile–glycidyl methacrylate (SAG) copolymers with various contents of glycidyl methacrylate (GMA) were used to compatibilize the incompatible blends of styrene–acrylonitrile (SAN) and a liquid crystalline polymer (LCP). These SAG copolymers contain reactive glycidyl groups that are able to react with the carboxylic acid and/or hydroxyl end groups of the LCP to form the SAG‐g‐LCP copolymers during melt processing. The in situ–formed graft copolymers tend to reside along the interface to reduce the interfacial tension and to increase the interface adhesion. The morphologies of the SAN/LCP blends were examined by using scanning electron microscopy (SEM), where the compatibilized SAN/LCP blends were observed with greater numbers and finer fibrils than those of the corresponding uncompatibilized blends. The mechanical properties of the blends increased after compatibilization. The presence of a small amount (200 ppm) of ethyl triphenylphosphonium bromide (ETPB) catalyst further promotes the graft reaction and improves the compatibilization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3321–3332, 2001
Curing kinetic of the epoxy system badge n = 0/1,2 DCH by fourier transform infrared spectroscopy (FTIR)
Authors: Fraga F. , Burgo S. , Núñez E. Rodríguez 
Published: October 2004

AbstractThe curing reaction of an epoxy system consisting of a diglycidyl ether of bisphenol A (BADGE n = 0) and 1,2‐diaminocyclohexane (DCH) was studied by Fourier Trasform Infrared Spectroscopy (FTIR). From the infrared spectra using a peak‐height method, that was based on the ratio of the height of the characteristic to reference absorbance peak, degree of conversion at different isothermal temperatures were calculated. From a kinetic study, the Horie et al. model was used; parameters such as rate constants and activation energies were determined. The results were compared to those obtained for same epoxy systems using scanning differential calorimetry (DSC). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3366–3372, 2001
Synthesis, structure, and characterization of polymeric stationary phase derived from (R,R)‐tartramide and bisphenol‐S
Authors: Jabłońska‐Pikus T. , Charmas W. , Podkościelna B. , Gawdzik B. 
Published: October 2004

AbstractThe preparation of a new chiral polymeric stationary phase for chromatography is presented. A porous copolymer of mono‐ and dimethacrylate derivatives of bisphenol‐S and divinylbenzene containing hydroxyl functional groups was used as a matrix. (3‐Aminopropyl)triethoxysilane was used as a coupling agent and was bonded to these groups. The obtained compound was transferred into a final product during a three‐step synthesis. The properties of the obtained polymeric phase with the chiral moiety were studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3409–3417, 2001
Thermal oxidation kinetics for a poly(bismaleimide)
Authors: Colin X. , Marais C. , Verdu J. 
Published: October 2004

AbstractThe thermal oxidation of poly(bismaleimide) of the F655‐2 type, supplied by Hexcel‐Genin, was studied by isothermal gravimetry at 180, 210, and 240°C and various oxygen pressures ranging from 0 to 1.2 bar. Comparison of various sample thicknesses and visible microscopy observations on bulk aged samples shows that the whole oxidized layer has a depth of about 75 μm at 240°C, 138 μm at 210°C, and 229 μm at 180°C. An attempt was made to build a kinetic model to predict this depth. It is based on a differential equation in which O2 diffusion and its consumption rate, r(C), are coupled, C being the O2 concentration. Its resolution needs two sets of experiments: the first one to determine the O2 diffusivity and solubility in the polymer, and the second one to determine r(C). The mathematical form of r(C) is derived from a mechanistic scheme of radical chain oxidation in which initiation is mainly due to POOH decomposition. This expression contains two kinetic parameters, α and β, the values of which are determined from the experimental curves of mass loss rate against O2 pressure (in the stationary state). The theoretical predictions, at each temperature under consideration, are in excellent agreement with experimental results. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3418–3430, 2001