bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of acid‐cured epoxide resins with different network structures
Authors: Shimbo Masaki , Nishitani Nobuhisa , Takahama Takashi 
Published: April 2003

AbstractStatic and dynamic mechanical properties of cured epoxide resins based on ester bonds, ether bonds, or a mixture of ester and ether bonds were investigated. Their network structures were estimated from the results of gel content before and after saponification, and conversion of functional groups. It was found that cured epoxide resins based on a mixture of ester and ether bonds indicate intermediate properties between the resins based on ester bonds and the resins based on ether bonds. Both dynamic and static mechanical properties were strongly affected by their network density and their segmental structures suggested in this paper.
Fourier transform infrared spectroscopic characterization of aromatic bismaleimide resin cure states
Authors: Di Giulio C. , Gautier M. , Jasse B. 
Published: April 2003

AbstractInteresting polyimide materials, possessing good mechanical and thermal properties, are obtained by homopolymerization or reaction of 4,′4‐bis(maleimidodiphenylmethane) with a diamine. Fourier transform infrared spectroscopy has been used to characterize the crosslinking of such materials using maleimide and amine absorption bands. Amine group reaction on double bonds is readily achieved and appears to be insensitive to the temperature of curing. On the other hand, the decrease of maleimide double bonds is strongly dependent on the reaction temperature. The residual amount of double bonds present in the cured material is a function of the temperature: a linear relationship holds between residual double bond concentration vs. curing temperature. The general behavior during crosslinking of this kind of polyimide was related to glass transition temperature changes.
Effect of processing conditions on premature gelling, knit line strength, and physical properties for the RIM process
Authors: Castro J. M. , Macosko C. W. , Critchfield F. E. 
Published: April 2003

AbstractIt is shown how using the relevant dimensionless groups for the RIM process, guidelines for premature gelling, and knit line problems can be achieved. The influence of processing conditions on final plaque physical properties is analyzed. It is shown that RIM parts, due to the fact that most of the polymerization reaction occurs after the mold is filled, are fairly isotropic with respect to planar rotations parallel to the mold walls.
Latex interpenetrating polymer networks based on acrylic polymers. I. Predicted and observed compatibilities
Authors: Hourston D. J. , Satgurunathan R. 
Published: April 2003

AbstractAn investigation of the compatibilities of several acrylic latex interpenetrating polymer networks is the subject of this paper. Initially the compatibilities of the various polymer pairs were predicted using the theory of Krause plus some direct measurement of heats of mixing of monomers and of model compounds. The materials were then synthesized using emulsion polymerization, and the extents of mixing of the components were investigated using dynamic mechanical analysis.
Polycarbonate blends with styrene/acrylonitrile copolymers
Authors: Keitz J. D. , Barlow J. W. , Paul D. R. 
Published: April 2003

AbstractLap shear adhesion between laminated sheets of polycarbonate and styrene/acrylonitrile copolymers exhibits a sharp maximum when the acrylonitrile content of the copolymers is in the range of 25–27% by weight. Observations of shifts in glass transitions of the two phases in melt‐mixed polycarbonate/SAN blends suggest partial miscibility of one polymer in the other, and this solubility is at a maximum when the SAN copolymer has an acrylonitrile content in the same range causing maximum adhesion. Mechanical properties of injection‐molded blends of polycarbonate with various SAN copolymers were also best when the acrylonitrile content was the same as that giving maximum adhesion. The partial miscibility behavior in blends as a function of acrylonitrile content of the copolymer is explained qualitatively in terms of a simple binary interaction model.
Application of thermal conductivity detection for investigating the diffusion of component X in the system: A mixture of vapors of X and Y substances–polymer membrane–Y substance vapor
Authors: Izydorczyk Jan , Salwinski Janusz 
Published: April 2003

AbstractThermal conductivity detection has been applied for determining the mass transport coefficients of vapor through polymer membranes in the presence of another vapor being in equilibrium with polymer. Apparatus and measuring technique have been described. Diffusion, permeability, and solubility coefficients have been determined for systems comprising polyethylene membrane and two‐component vapor mixtures of selected substances. It has been found that the presence of nonpolar substances affected diffusion, permeability, and solubility coefficients of polar penetrants in the systems investigated. Analysis of the results obtained in evaluating the possibility and correctness of the determination of diffusion and permeability coefficients derived from mathematical descriptions of the process of permeating a single substance has been carried out.
Preparation of tri‐O‐substituted cellulose ethers by the use of a nonaqueous cellulose solvent
Authors: Isogai Akira , Ishizu Atsushi , Nakano Junzo 
Published: April 2003

AbstractThe previously reported method for the preparation of tri‐O‐benzylcellulose was applied to the preparation of various tri‐O‐substituted cellulose ethers. By this method, in which a mixture consisting of SO2, diethylamine (DEA), and dimethylsulfoxide (DMSO) and powdered sodium hydroxide were used as a cellulose solvent and a base, respectively, many tri‐O‐arylmethylcelluloses could be prepared from the corresponding chlorides. Cellulose ethers containing double bonds such as tri‐O‐allyl, tri‐O‐methallyl‐, and tri‐O‐2‐butenylcellulose were also prepared from the corresponding chlorides under a milder condition than that used for the preparation of tri‐O‐arylmethylcelluloses. Reaction factors accelerating complete etherification were discussed.
A “chain fold band” in the infrared spectra of nylon 6
Authors: Hallos R. S. 
Published: April 2003

AbstractAn absorption band found at 974 cm−1 in the infrared spectra of “amorphous” nylon 6 films has been assigned to CH2 wagging or twisting vibrations in molecular chain folds. Annealing amorphous films in air at increasing temperatures up to 150°C has been shown to induce a steady increase in the intensity of the absorption band at 974 cm−1. Annealing at higher temperatures resulted in a sharp decrease in intensity up to an annealing temperature of 210°C. This sharp decrease coincided with a sharp increase in the long period determined by low‐angle x‐ray diffraction studies. Drawing amorphous films has been shown to induce a decrease in the intensity of the band at 974 cm−1. Polarized infrared investigations of amorphous drawn films revealed that the band at 974 cm−1 was strongly perpendicular in character. Treatment of amorphous films in water induced no frequency change in the band at 974 cm−1.
Synthesis and transport properties of thin film composite membranes. I. Synthesis of poly(phenylene oxide) polymer and its sulfonation
Authors: Huang R. Y. M. , Kim J. J. 
Published: April 2003

AbstractThe synthesis of sulfonated poly(phenylene oxide) polymer was investigated. The poly(phenylene oxide) was synthesized through oxidative coupling from 2,6‐dimethyl‐phenol with copper (I) chloride‐pyridine catalyst and sulfonated using chlorosulfonic acid. The effects of catalyst concentration, solvent, and other experimental variables on the kinetics of the polymerization of poly(phenylene oxide) and its subsequent sulfonation are reported in detail.
Synthesis and characterization of BDSDA/APB polyimide
Authors: Burks Harold D. , St. Clair Terry L. 
Published: April 2003

AbstractA novel linear aromatic polyphenylene ethersulfideimide (BDSDA/APB) has been synthesized. Its physical, mechanical, thermal, and flow properties and its resistance to some of the more commonly used solvents were determined. The results of these property evaluations indicate this polymer system can be processed via conventional thermoplastic techniques. It has been molded, used as a resin, and cast into thin films and, accordingly, may have a wide variety of applications. Its molecular weight was varied by endcapping with phthalic anhydride. Over the M̄n range 14,000–45,000 the apparent viscosities and GIc values varied only slightly. However, a change in M̄n from 14,000 to 8700 resulted in a dramatic decrease in the apparent viscosity at both 250°C and 280°C. The GIc values for these same molecular weight materials decreased in a like manner as the M̄n decreased, indicating tradeoffs can be made between process optimization and final mechanical properties when polymer systems are developed.
Thermal stability, fractionation, and chemical modification of chlorinated rubbers. I. Infrared and 13C‐NMR study of the structure of chlorinated natural rubber modified under various experimental conditions
Authors: Makani Siku , Brigodiot Maryvonne , Maréchal Ernest , Dawans François , Durand Jean‐Pierre 
Published: April 2003

AbstractThe structure of chlorinated natural rubber (CR) was studied by infrared and NMR spectroscopy. It was shown that the structure proposed by Troussier (thèse de Docteur‐Ingénieur, Lyons, 1954) does not fit the 13C‐NMR characteristics of this compound. CR was fractionated and each fraction was characterized. The thermal stability of CR and the evolution of its structure in various experimental conditions was studied by NMR.
Mechanical properties of paper sheets prepared from partially cyanoethylated wood pulp
Authors: El‐Shinnawy Nabila A. , El‐Kalyoubi Samira F. 
Published: April 2003

AbstractCyanoethylated of wood pulp was carried out at different conditions including acrylonitrile concentration, time, and temperature of the reaction. Some mechanical properties of paper sheets prepared from the cyanoethylated wood pulp were examined. Cyanoethylated paper sheets acquired higher breaking length, fold number, and burst factor than the untreated paper sheets irrespective of the conditions used for cyanoethylation. On the other hand, the tear factor of cyanoethylated paper sheets was generally lower than that of the untreated control through under certain conditions cyanoethylation brought about substantial improvement in tear factor. The water retention value and beating time are decreased depending upon the condition of cyanoethylation used.
Crosslinkable polyamide–imides
Authors: Serna Felipe J. , De Abajo Javier , De La Campa José G. 
Published: April 2003

AbstractA series of polyamide–imides were prepared from aromatic diamines and substituted isophthaloyl chlorides containing unsaturated imide rings. Aromatic polyamides from isophthaloyl chloride were also prepared for comparison. The polyamide‐imides gave enhanced solubility compared to the aromatic polyamides and there was no deterioration in thermal stability orTg. The PAIs were crosslinked by heating at 280°C/4 h under nitrogen. After this heat treatment all the PAIs became insoluble and their mechanical properties increased substantially; their thermal behavior, as measured by DSC and TGA, changed as a function of their chemical structure.
Thermal decomposition behavior of poly[3,3‐bis(ethoxymethyl) oxetane] and related polyethers
Authors: Jones R. B. , Murphy C. J. , Sperling L. H. , Farber M. , Harris S. P. , Manser G. E. 
Published: April 2003

AbstractThe thermal decomposition behavior of poly[3,3‐bis(ethoxymethyl)oxetane] (polyBEMO) was examined and compared to the decomposition of poly(ethylene oxide) (PEO) and poly(tetramethylene oxide) (polyTHF). Differential scanning calorimetric (DSC) studies as a function of heating rates and at constant temperature as a function of time yielded activation energies of 45–50 kcal/mol, characteristic of polyether decomposition. First‐order decomposition kinetics were found. The reaction is endothermic, with a heat of decomposition of 18.6 kcal/mol. Effusion mass spectroscopy on polyBEMO showed major peaks at 112, 140, 168, and 174 amu. A mechanism is proposed in which the thermal scission of the ether bonds in both the polymer chain and in the appendanges initiates the decomposition. The main decomposition reaction for polyBEMO can be written as
magnified image
where the appendages and main chain are cleaved in an unknown order.
Open‐cell flexible polyurethane foams: Comparison of static and dynamic compression properties
Authors: Shuttleworth R. W. , Shestopal V. O. , Goss P. C. 
Published: April 2003

AbstractDynamic stress–strain diagrams of polyurethane packaging foams have been obtained from free fall drop tests. The dynamic curves become higher as the deformation rates increase. An equation is proposed to describe the stress–strain dependence for different deformation rates. The model of filament buckling explains the form of the observed stress–strain dependence and phenomena related to repeated loading of the foam.
The viscoelastic properties of rubber–resin blends. I. The effect of resin structure
Authors: Class J. B. , Chu S. G. 
Published: April 2003

AbstractBlends of elastomers with the proper concentration of appropriate low molecular weight resins exhibit performance as pressure sensitive adhesives. Viscoelastic properties, which may be related to adhesive performance, were measured on 1:l blends of rubber and resin using a mechanical spectrometer. Significant differences in viscoelastic properties were observed depending upon the resin structure. On plots of G′ and tan δ vs. temperature, the addition of a compatible resin produces a pronounced shift of the tan δ peak to a higher temperature and reduces the modulus in the rubbery plateau. An incompatible resin results in a minor shift in the tan δ peak of the elastomer along with the appearance of a second peak at higher temperature, attributed to a second phase which is predominantly resin. Also, the modulus is increased in the rubbery plateau. A polystyrene resin, Mw about 900, is shown to be incompatible with natural rubber but compatible with styrene–butadiene rubber. A cycloaliphatic poly(viny1 cyclohexane) resin, Mw about 650, prepared by hydrogenating the polystyrene resin, is compatible with natural rubber, but incompatible with styrene‐butadiene rubber. An alkyl‐aromatic poly(tert‐butylstyrene) resin, Mw about 850, which is intermediate in aromaticity between the aromatic polystyrene resin and the cycloaliphatic poly(viny1 cyclohexane) resin, is compatible with both natural rubber and styrene‐butadiene rubber. Therefore, the structure of the resin is very important in adjusting the viscoelastic properties of a rubber–resin blend to achieve pressure sensitive adhesive performance.
Thermal degradation of liquid polysulfide polymers: Pyrolysis–GC–MS and thermogravimetric studies
Authors: Rao M. Rama , Radhakrishnan T. S. 
Published: April 2003

AbstractThe thermal decomposition of Thioped, a liquid polysulfide polymer based on dichloroethyl formal, was studied using pyrolysis–GC–MS. The nature and composition of the products of pyrolysis at 358 and 485°C are given. A striking feature of the product analysis is the presence of several disulfide compounds only at the higher decomposition temperature. The pyrolysis‐GC of other liquid polysulfide polymers (LP‐2, LP‐32, LP‐3, and LP‐33) showed that molecular weight had only marginal effect on the product composition. Ionic and radical mechanisms were considered to account for the product formation. Isothermal and dynamic thermogravimetric studies were carried out to differentiate between the two mechanisms. The results were found to be in agreement with a free radical mechanism, with cleavage of the formal CO linkage as the preferred mode of initiation. The overall activation energy for the decomposition was found to be 190 kJ mol−1.
A study on graft copolymerization of methyl methacrylate onto jute fiber
Authors: Tripathy S. S. , Jena S. , Misra S. B. , Padhi N. P. , Singh B. C. 
Published: April 2003

AbstractA kinetic study of the graft copolymerization of methyl methacrylate onto jute fiber using KMnO4–malonic acid redox initiator system has been made. Effects of the concentrations of malonic acid, monomer, and KMnO4 on graft yield have been studied. Besides, the effects of temperature, acid, and reaction medium, some inorganic salts on graft yield have been investigated. The most remarkable features of the investigation include the proposition of a mechanism, derivation of rate expression for the grafting process, and characterization of the grafted fiber by thermogravimetric analysis.
Protection of wood surfaces against photooxidation
Authors: Hon David N.‐S. , Chang Shang‐Tzen , Feist William C. 
Published: April 2003

AbstractProtection of wood surfaces against photoinduced oxidative degradation can be achieved by using effective coating agents. Several penetrating chemical agents, such as triol‐G 400, PEGG 400, and 1‐octadecanol, were shown to provide good protection for wood surfaces against discoloration during ultraviolet irradiation. In addition, wood surfaces coated with clear film‐forming finishes, such as homo‐ and copolymers of 2‐hydroxy‐4 (3‐methacryloxy‐2‐hydroxy‐propoxy) benzophenone, exhibited outstanding performance into inhibiting discoloration and surface deterioration. Infrared and ultraviolet absorption spectra and scanning electron microscopy studies revealed that the clear polymeric coatings containing an internal UV absorber were very stable and resistant to photooxidation. Possible chemistry and mechanisms of protection of wood surfaces provided by these polymeric coating systems are discussed.
Structure–property relationships of thermally bonded polypropylene nonwovens
Authors: Wei K. Y. , Vigo T. L. , Goswami B. C. 
Published: April 2003

AbstractThe effect of fiber structure and morphology on the resultant mechanical and low load deformation properties of thermally bonded nonwoven polypropylene fabrics has been studied. Commercially available staple polypropylene fibers varying in linear density and draw ratio (Herculon and Marvess staple fibers) were used in this study. The orientation of these fibers was characterized by birefrigence measurements. Differential scanning calorimetry measurements were made to determine the heat of fusion and melting point of fibers. Experiments confirm that tensile strength and stiffness of the fabrics correlate with this fiber structure. Under the same bonding conditions fabrics made from fibers with low draw ratios show higher tensile strength and stiffness than do fibers with high draw ratios. The mechanical properties of fabrics were found to be greatly affected by the thermal bonding temperature. The tenacity and flexural rigidity of fabrics made from poorly oriented fibers show higher values than those made from highly oriented fibers. The shrinkage of the fabrics was observed to increase with increasing bonding temperature in both machine and cross machine directions. The changes in fabric thickness due to the thermal bonding are considerably lower for poorly oriented fibers.
Glass transition in aliphatic polyamides
Authors: Botta A. , de Candia F. , Palumbo R. 
Published: April 2003

AbstractThe glass transition temperature is analyzed in polyamide systems characterized, owing to their chemical composition, by the absence of hydrogen bonds. The physical behavior exhibited by these systems is similar to that observed in conventional aliphatic polyamides, suggesting that, besides the hydrogen bonds, the amidic group itself plays a specific and important role in determining the polymer physical behavior generally and, in particular, the glass transition mechanism. It is surmised that this role is connected with the polar and rigid character of the amidic group, affecting chain‐chain interactions and chain mobility.
Blends of nylon 6 with an ethylene‐based multifunctional polymer. II. Property–morphology relationships
Authors: Chuang Hsiao‐Ken , Han Chang Dae 
Published: April 2003

AbstractThe tensile properties and impact strength were measured of the three blend systems, nylon 6/CXA 3101, nylon 6/Plexar 3, and nylon 6/EVA, which had been prepared using a twinscrew compounding machine. Scanning electron micrographs (SEM) of the fracture surfaces show that the domain size of the dispersed phase is much smaller in the nylon 6/CXA 3101 blends or nylon 6/Plexar 3 blends than in the nylon 6/EVA blends. This is attributed to the presence of a graft copolymer, formed by chemical reactions between carboxyl or anhydride groups present in the CXA 3101 (or Plexar 3) and the amino end groups of the nylon 6, at the boundaries of the dispersed and continuous phases. The SEM analysis of the fracture surfaces shows that no discrete particles are exposed on the fracture surface of either the nylon 6/CXA 3101 blends or nylon 6/Plexar 3 blends, supporting the theory that a graft copolymer, formed during melt blending, helped the discrete particles adhere to the continuous matrix.
The differential viscometer. II. On‐line viscosity detector for size‐exclusion chromatography
Authors: Haney Max A. 
Published: April 2003

AbstractThe new technique of differential viscometry measures directly the specific viscosity of a solution by subtracting the contribution of solvent in a balanced capillary bridge. The present work adapts the differential viscometry principle to the design of a viscosity detector for use in size‐exclusion chromatography. It is shown that the resulting viscosity detector possesses excellent sensitivity and baseline stability with a minimum detectable specific viscosity of 2.7 × 10−5. The viscosity detector can be operated together with a refractive index detector to determine the intrinsic viscosity of polymer solute fractions as they elute from the SEC column. The bandspreading of the viscosity detector is compared to the refractive index detector by measuring the peak width of a compound having a single discrete molecular weight. The peak width at half‐height was 0.29 mL for the viscosity detector and 0.25 mL for the refractive index detector.
Durability of radiation‐sterilized polymers. I. Estimation of oxidative degradation in polymers by chemiluminescence
Authors: Yoshii Fumio , Sasaki Takashi , Makuuchi Keizo , Tamura Naoyuki 
Published: April 2003

AbstractIn relation to sterilization of medical supplies, the degree of degradation by γ‐ray and electron beam irradiations of homopolypropylene (HP), copolypropylene (CP, coplymer including 6% of ethylene unit) and polymethylpentene were compared, and chemiluminescence (CL) of irradiated polymers were measured. HP degraded extremely around the sterilization dose (2.5 Mrad) by either γ‐ray or electron beam irradiations. In the case of CP and polymethylpentene, stabilities of polymers far differed between γ‐ray and electron beam irradiations. The polymethylpentene was more stable than the polypropylenes against irradiation. The counts of CL emitted by recombination of peroxy radical (ROO ·) increased with increasing dose, reflecting degrees of oxidation of polymers. The degradation of polymers was independent of irradiation sources, rather it depended on the degree of oxidation. It was found that CL analysis are favorable for estimation of degradation in irradiated polymers.