bluuebunny/crossref_metadata_2025 huggingface dataset:
Permeability through cellulose membranes grafted with vinyl monomers in a homogeneous system. VIII. N‐vinylpyrrolidone‐grafted cellulose membranes
Authors: Nishioka Noboru , Tsuetaki Motoji , Kato Ryoichi , Uno Masakuni
Published: April 2003

The homogeneous grafting of N‐vinylpyrrolidone (NVP) onto cellulose was carried out in a dimethyl sulfoxide/paraformaldehyde (DMSO/PF) solvent system. The diffusive permeabilities of solutes through the NVP‐grafted cellulose membranes, apparent activation energy for solute permeation through them, states of water in them, and their microphaseseparated structures were investigated. The solute permeability through the grafted membranes was superior to that through the cellulose membrane cast from the DMSO/PF solution of cellulose. The total water and nonfreezing water contents of the grafted membranes were larger than those of the cellulose membrane. The difference in permeability through the membranes was not correlated quantitatively with the amount of each state of water in them. Activation energies for permeation of solutes through the grafted membranes were similar to those through the cellulose membrane. © 1994 John Wiley & Sons, Inc.
Effect of polymeric steric stabilizers on the settling of alumina
Authors: Armstrong G. H. , Johnson L. , Parker A. A.
Published: April 2003

The effect of polymeric steric stabilizers on the dispersion stability of alumina was determined by settling experiments. The theoretical settling density was determined for alumina in a 90:10 wt% toluene‐ethanol mixed solvent. Polymers evaluated were sulfonated polystyrenes, Shell's functionalized Kraton block polymers (styrene‐hydrogenated diene), ICI's polymeric surfactants, homopolystyrene, a nonfunctionalized Kraton block polymer, and two Union Carbide Corporation silwet surfactants. The high‐molecular‐weight sulfonated polystyrene (60,000) containing a low level of sulfonation, functionalized Kraton block polymers, and one ICI polymeric surfactant were effective in improving the dispersion stability of the alumina. The percent of theoretical settling density for the “good” polymeric steric stabilizers ranged from 45 to 50%. The low‐molecular‐weight sulfonated polystyrene (10,000 MW), homopolystyrene, unfunctionalized Kraton block polymer, one ICI polymeric surfactant, and the silwet surfactants were ineffective in improving the dispersion stability of the alumina in the mixed solvent. © 1994 John Wiley & Sons, Inc.
Effect of antioxidants on properties and morphology of poly(acrylonitrile–butadiene–styrene)/polycarbonate blends
Authors: Yan Rong Jiang , Yang Bingxin
Published: April 2003

Poly(acrylonitrile–butadiene–styrene), polycarbonate (PC), and two types of antioxidants have been blended by an extruder twin screw. Notched Izod impact strength, tensile property, and melting flow index (MFI) were measured for the blends including different amounts of antioxidants, and morphology of the blends was investigated by scanning electron microscopy (SEM). The antioxidant action, especially on mechanical properties and the phase structure of the blends, has been studied for the undergraded samples. It was found that the phenolic antioxidant, tetrakis (3,5‐di‐tert‐butyl‐4‐hydroxyhydrocinnamoyloxy‐methyl) methane, C73H108O12, whose commercial name is KY‐7910, and phosphite antioxidant, triphenyl phosphite (TPP), (C6H5O)3P, all decrease the Izod impact strength and tensile modulus of the blends and increase the elongation at break if a small amount of the antioxidants (such as less than 0.7%) was mixed into the blends. When the content of the antioxidants is increased, surpassing 0.7%, KY‐7910 has little effect on impact property of the blends, but TPP made the Izod impact strength decrease and the MFI increase to a great degree. SEM results show that the two phases of ABS/PC with a weight ratio of 30/70 is cocontinuous; this structure is destroyed by addition of the two antioxidants, and in ABS/PC/antioxidants blends, the size of the ABS phase, as dispersion, does not change not much with increasing KY‐7910 content, but becomes more scattered and greater with increasing content of TPP. These results are consistent with the mechanical tests. © 1994 John Wiley & Sons, Inc.
Effect of moisture and orientation on the fracture of nylon 6,6 fibers
Authors: Michielsen S.
Published: April 2003

The effect of relative humidity on the fracture of single nylon 6,6 fibers is determined using fracture mechanics. The fracture energy release rate, GIc, of these fibers is shown to be 8× that for injection‐molded nylon 6,6 at 0% RH. GIc varies from 31.3 kJ/m2 at 0% RH to 15.6 kJ/m2 at 100% RH. The dependence of GIc on RH is in agreement with previous studies indicating two types of water in nylon: a tightly bound and a loosely bound type. In addition, GIc is shown to be 10× greater for transverse fiber breaks than for axial splitting of the fiber due to the high degree of orientation in these fibers. These studies are the first of their kind for organic fibers. © 1994 John Wiley & Sons, Inc.
Glycidyl‐terminated polyurethane modified epoxy resins: Mechanical properties, adhesion properties, and morphology
Authors: Hsia Hung‐Chung , Ma Chen‐Chi M. , Li Ming‐Shiu , Li Ye‐Shiu , Chen Der‐Shyang
Published: April 2003

Glycidol was used to convert the isocyanate‐terminated polyurethane prepolymer to glycidyl‐terminated polyurethane prepolymer. The modified polyurethane not only offers some distinct advantages over the commercial polyurethane prepolymer, but also enhances the properties of the epoxy resins. The glycidyl‐terminated polyurethane modified epoxy resin proved to be superior to conventional epoxy resins in improving impact strength, fracture energy, and adhesion properties. The compatibility of the compounds in this glycidyl‐terminated PU/epoxy system was investigated using different preparation procedures. It was found that the synthesized glycidyl‐terminated polyurethane prereacted with curing agents, exhibited a lesser degree of phase separation, and can influence the mechanical properties of polymer blends. The results coincide with the phenomena observed in dynamic mechanical analysis and scanning election microscopy. © 1994 John Wiley & Sons, Inc.
Solid‐state NMR characterization of motion in flexible polyurethane foams
Authors: Moreland J. C. , Wilkes G. L. , Moreland C. G. , Sankar S. S. , Stejskal E. O. , Turner R. B.
Published: April 2003

High‐resolution solid‐state 13C‐NMR has been used to study the phase separation and molecular motion in two series of polyurethane foams. These two series differ by one possessing the additive of lithium chloride, LiCl. NMR relaxation times can map the motion throughout the polymer molecule and detect changes in that motion arising from either microseparation or phase mixing between the different segments. There are only slight changes in the soft segment T1p(13C) values as well as an increase in the hard segment T1p(1H) values with increase in the hard segment content for the foams studied. The T1p(1H) and T1p(13C) values do indicate that the phase separation of the hard and soft segments is similar for all foams. A decrease in the T1p(1H) and T1p(13C) values with increasing LiCl content indicates that the motion of the soft segments is restricted more by the hard segments. This is explained by more phase mixing in the foams containing the LiCl additive. © 1994 John Wiley & Sons, Inc.
Catalytic transesterification in polycarbonate–polycaprolactone systems
Authors: Shuster M. , Narkis M. , Siegmann A.
Published: April 2003

Bisphenol A polycarbonate (PC)–poly‐ε‐caprolactone (PCL) blends have been prepared by melt mixing in the presence of different catalysts using a Brabender plastograph and single‐screw extruder at 240–260°C. Increased crystallizability [detected by differential scanning calorimetry (DSC)] of the PC component was observed in the blends obtained in the presence of p‐toluenesulfonic acid. Acceleration of carbonate‐carbonate exchange reactions is suggested as the main reason for the crystallizability enhancement. Results of solubility tests, DSC, and infrared (IR) spectroscopy evidence ester‐carbonate transesterification taking place during PC–PCL blending in the presence of tetrabutoxy titanium and dibutyltin dilaurate. © 1994 John Wiley & Sons, Inc.
The effects of soft segments on the physical properties and water vapor permeability of H12MDI‐PU cast films
Authors: Yen M. S. , Cheng K. L.
Published: April 2003

This research was based on the study of the effects of H12MDI‐1, 4BD PU soft segments on the physical properties and water vapor permeability of films cast from solvent evaporation or wet coagulation method. The soft segments studied included polyether, polyester, and polycaprolactone polydiols. The NCO/OH mol ratios of prepolymer were prepared by 2, 3, 4, 5, and 8, respectively. The chain lengths of the soft segments used were: PTMG of molecular weights 650, 1000, 2000, and 2900; PBA of 1000, 2000, and 3000. The results revealed that the polyether‐based PU cast films had lower Tgs than the polyester‐based PU films. In general, the polyether‐based PU films shows the characters of higher water vapor permeability, lower breaking elongation, and higher breaking strength. Films with higher molecular weight soft segments in the polymer chains exhibited lower Tgs, lower breaking strength, higher breaking elongation, and higher water vapor permeability. As the hard segment contents were increased, the films exhibited higher Tgs. Films with higher hard‐segment ratios had the highest breaking strength but the water vapor permeability, on the other hand, became lower. Films cast from the solvent evaporation method had higher breaking strength and higher breaking elongation but lower water vapor permeability than films cast from the wet coagulation method. © 1994 John Wiley & Sons, Inc.
The effect of fillers on relaxation phenomena of vulcanized styrene–butadiene elastomers
Authors: Čvorkov Ljubomir , Vlatković Biljana , Veličković Jovan
Published: April 2003

Standard recipe mixtures, based on styrene/butadiene rubber SBR 1500 and oil‐extended SBR 1712, with varying amounts of carbon black, silica, or kaoline fillers were prepared and the stress relaxation curves of vulcanized samples were determined. The measurements were restricted to slow relaxation phenomena, observed after 50% initial elongation. Three λ‐processes and a fourth ϕ‐process, existing only in filled rubbers, were observed. The relaxation times and activation energies, determined graphically, reflect the amount and activity of the fillers. All relaxation times are lower for filled vulcanizates and decrease with increasing temperature; however, the type of filler does not affect the activation energy. The higher parameters observed for the ϕ‐processes are discussed in terms of filler particle mobilities and rearrangements and of filler/rubber contact layer phenomena. © 1994 John Wiley & Sons, Inc.
Analysis of ultrasonically induced free radicals in the emulsion polymerization system by GC–MS
Authors: Liu Youbang , Chou Hsin‐Chieh , Stoffer James O.
Published: April 2003

A specially designed gas chromatography–mass spectrometry (GC–MS) analytical method has been developed and applied to identify the source of free radicals that served as initiators in a new ultrasonically induced emulsion polymerization system with monomer methyl mathacrylate (MMA), surfactant sodium dodecylsulfate (SDS) and water. The results showed the radicals came from the dissociation of SDS under ultrasonic irradiation. A quantitative determination procedure has been also developed and utilized to investigate the effects of the polymerization parameters, such as the surfactant concentration, the acoustic intensity of ultrasound, and the argon flow rate on the concentration of the generated free radicals in the emulsion system under ultrasonic irradiation. The results were helpful to understand the mechanism and kinetics of the system. © 1994 John Wiley & Sons, Inc.
A squeeze film flow processibility tester
Authors: Pham Hoang T. , Meinecke Eberhard A.
Published: April 2003

The applicability of the squeeze film flow geometry in a processibility tester is investigated in this study. A prototype processibility tester has been built by retrofitting it to a servohydraulic load frame. Several processibility parameters such as viscosity and the elastic component in the melt have been investigated. With the concept of equivalent elastic strain, the extrudate swell can be semi‐quantitatively predicted from the squeeze film flow experiment. © 1994 John Wiley & Sons, Inc.
EVA–EPDM blends as cable insulant
Authors: Ray I. , Khastgir D.
Published: April 2003

Base materials for heat‐resistant cable insulant have been developed from blends of ethylene vinyl acetate (EVA) copolymer containing 28% VA and ethylene propylene diene (EPDM) rubber. Different electrical, mechanical, and thermal properties of these blends have been studied extensively. Aging under different conditions has also been studied. The chemical and mechanical stability of these compositions has been assessed at the actual temperature range of application. Dielectric properties have been determined against varying temperature. These blends may be used as insulating materials having a temperature rating around 90–130°C, which is above the temperature rating (85–90°C) of heat‐resistant insulation based on EPDM. © 1994 John Wiley & Sons, Inc.
Composite membranes of poly(1‐trimethylsilyl‐1‐propyne) and poly(dimethyl siloxane) and their pervaporation properties for ethanol–water mixture
Authors: Kang Yong Soo , Shin Eun Mi , Jung Bumsuk , Kim Jae‐Jin
Published: April 2003

A poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) membrane was systematically modified to prevent flux decline over time by incorporating poly(dimethyl siloxane) (PDMS) in three different ways: (1) semi‐interpenetrating polymer network (I series), (2) PDMS sorption (S series), and (3) PDMS sorption and crosslinking (X series). The PTMSP and PDMS phases were partially mixed in the I series, which was confirmed by the measurement of density and glass transition temperature. The flux and separation factor in pervaporation of an ethanol–water mixture decrease with time for the I series, analogous to the behavior of pure PTMSP. However, the flux and separation factor remained steady with time in the case of the S and X series. The sorption method appears to be a good means for maintaining a time‐unvarying flux and separation factor at a minimum expense. © 1994 John Wiley & Sons, Inc.
Relaxations in thermosets. XXIX. Calorimetric studies of the curing kinetics of nonstoichiometric diamine–epoxy mixtures
Authors: Wasserman S. , Johari G. P.
Published: April 2003

The curing kinetics of nonstoichiometric mixtures of diglycidyl ether of bisphenol A, with ethylene diamine, propylene diamine, and hexamethylene diamine have been measured under both isothermal and ramp‐curing condition. Their kinetics are faster than for stoichiometric compositions and the reactions reach completion. The total heat evolved for the amine‐rich composition is greater than for the amine‐deficient. None of the available formalisms is consistent with the results. This and the variation in the heat of reaction indicate that steric effects are important for both the reaction rate and the heat evolved. It is argued that the standard heat of reaction of primary amine with the epoxide group differs from that of secondary amine. © 1994 John Wiley & Sons, Inc.
Self‐crosslinkable blend of zinc‐sulfonated EPDM and epoxidized natural rubber
Authors: Manoj N. R. , De P. P. , De S. K. , Peiffer D. G.
Published: April 2003

The zinc‐sulfonated EPDM (SEPDM)–epoxidized natural rubber (ENR) blend is selfcrosslinkable in the sense that it undergoes crosslinking on molding at high temperatures without the aid of any external curing agents. This is evident from Monsanto rheometric, solvent swelling, and infrared spectroscopic studies. The sulfonate anion is believed to react with an epoxide ring, leading to the formation of sulfonate ester and ether crosslinks. The extent of crosslinking depends on the degree of sulfonation of SEPDM and epoxidation level of ENR, the blend ratio, molding time, and temperature. Dynamic mechanical analyses of the blends show the immiscibility of the blend components. The chemical interaction is also manifested in the shift of the glass transition temperature of ENR to the hightemperature region. © 1994 John Wiley & Sons, Inc.
Pervaporation of ethanol–organic solvent mixtures through poly(2,6‐dimethyl‐1,4‐phenylene oxide) membrane
Authors: Schauer J.
Published: April 2003

Homogeneous dense membranes of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) were used to separate mixtures of ethanol—organic liquid by pervaporation. If the organic liquid had a strong affinity to PPO (e.g., toluene) and its concentration in the feed was low, smaller molecules of ethanol permeate preferentially through the membrane. When the concentration of this liquid in the feed was increased up to a certain value, the membrane was, on the contrary, permeated by it preferentially. When its concentration in the feed was further increased, flux through the membrane is dramatically increased and the membrane lost its selectivity. If the liquid in a binary mixture with ethanol in the feed had a low affinity to PPO (e.g., 1‐propanol), the selectivity of the PPO membrane virtually did not depend on the feed composition, and the membrane was preferentially permeated by smaller molecules. © 1994 John Wiley & Sons, Inc.
Development of in situ blends of poly(p‐oxybenzoate‐co‐p‐phenyleneisophthalate) with other thermotropic liquid crystalline polymers
Authors: Gupta Balaram , Calundann Gordon , Charbonneau Larry F. , Linstid H. Clay , Shepherd James P. , Sawyer Linda C.
Published: April 2003

A new in situ polymerization method is discussed wherein monomers of the major component are polymerized in the presence of a preformed thermotropic liquid crystalline polymer (LCP). Poly(p‐oxybenzoate‐co‐p‐phenyleneisophthalate) (HIQ) was chosen for this study. HIQ is well known to have a narrow process window and to be difficult to process reproducibly, both drawbacks for a commercial product. An in situ polymerization of the HIQ monomers in the presence of a fully polymerized LCP, such as poly(4‐oxybenzoate‐co‐6‐oxy‐2‐naphthoate) (CO) results in the “CO–HIQ” in situ blend. The in situ blend exhibited reduced biphasic morphology and was more homogeneous than was HIQ. The glass fiber‐filled CO–HIQ resin also featured improved melt flow and more reproducible mechanical properties than those of HIQ. The in situ blends were characterized by optical microscopy, 1H‐NMR, and melt rheology. The effect of the LCP level on the morphology of the in situ blend is discussed. © 1994 John Wiley & Sons, Inc.
Self‐assembled structures of azobenzene amphiphiles: A new photorecording medium
Authors: Gillberg G. , Leube H. , Mckenzie L. , Pruksarnukul L. , Reeder L.
Published: April 2003

The self‐assembly of azobenzene amphiphiles by themselves and in the presence of a nonionic polymer has been studied. The conditions that yield homeotropic and uniaxial films, i.e., the optical properties of a single crystal, by spin‐coating were identified. It is shown that these films constitute a very sensitive write and erase recording medium. © 1994 John Wiley & Sons, Inc.
Monoepoxy polymerization initiated by BF3‐amine complexes in bulk. III. Influence of γ‐butyrolactone on polymer formation
Authors: Chabanne Philippe , Tighzert Lan , Pascault Jean‐Pierre
Published: April 2003

The influence of γ‐butyrolactone (γ‐BL), used as solvent of BF3‐amine complexes, on the polymerization of monoepoxides was studied. Different intermediate reaction products of PGE initiated by BF3‐4‐methoxyaniline (BF3‐4MA) previously solubilized in γ‐BL (55% by weight), were separated and analyzed by 1H‐NMR. It is shown that there is the opening of both epoxy and γ‐BL. The latter does not homopolymerize, but copolymerizes well with epoxy groups. The use of a large quantity of γ‐BL leads to a decreasing molar mass of the formed polymer. The kinetic study allowed to propose the mechanism of the cationic polymerization of epoxy initiated by BF3‐amine complex in the presence of γ‐BL. © 1994 John Wiley & Sons, Inc.
Terminal attachment of perfluorinated polymers to solid surfaces
Authors: Rühe J. , Blackman G. , Novotny V. J. , Clarke T. , Street G. B. , Kuan S.
Published: April 2003

Physisorption and chemisorption of perfluoropolyethers on solid surfaces is investigated using infrared spectroscopy, microcalorimetry, ellipsometry, X‐ray photoelectron spectroscopy, and atomic force microscopy. Physisorbed polymers show shifts of vibrational modes to lower frequencies in a few nanometers thick films, indicating interactions with the solid surfaces. Hydroxyl‐terminated polymers are thermally attached to solid surfaces, and their thicknesses increase to saturated values with increasing heating time. The thermally attached thin polymer film consists of strongly physisorbed material as well as chemisorbed material. Strongly physisorbed polymer is slowly displaced from the surface by polar, low‐molecular‐weight compounds such as water or alcohols. This is to be expected on the basis of microcalorimetric results, which yield higher heats of immersion with water than with reactive perfluoropolyethers. Atomic force microscopy experiments show that the mobility of the polymer remaining on the surface decreases substantially as the amount of the physisorbed material decreases. © 1994 John Wiley & Sons, Inc.
Static and dynamic strain‐dependent viscoelastic behavior of black‐filled EPDM vulcanizates
Authors: Namboodiri C. S. S. , Tripathy D. K.
Published: April 2003

The strain dependence of the dynamic mechanical properties of HAF‐N330‐filled EPDM vulcanizate was studied using a Rheovibron DDV III EP. It is shown that when a dynamic strain is superposed on a static strain, the viscoelastic response of filled rubbers becomes more complex. Under these conditions, dynamic mechanical properties do not correlate with the double strain amplitude. A strain called the “total strain” has been defined in order to interpret the experimental results. It is also shown that the dynamic mechanical properties are displacement velocity dependent, while the comparison is made under identical conditions of strain and frequency. Separability of time and strain effects is observed for the storage modulus, whereas the loss modulus is shown to be a nonseparable function. The elastic and the relaxation components, constituting the mixed function representing the storage modulus are shown to have similar deformation dependence. © 1994 John Wiley & Sons, Inc.
Novel dielectrics from IPNs derived from castor oil based polyurethanes
Authors: Suthar Bhikhu , Klempner Daniel , Frisch Kurt C. , Petrovic Zoran , Jelcic Zelimir
Published: April 2003

Three series of interpenetrating polymer networks (IPNs) based on a polyurethane (castor oil + toluene diisocyanate) with polystyrene, poly(methyl methacrylate), and poly(n‐butyl methacrylate) were synthesized and characterized. Dielectric relaxation studies of these IPNs were carried out from −150 to 100°C in the 100 Hz to 100 kHz range. The effects of structural variables such as composition, type of vinyl monomer, as well as the effect of interaction of the phases on the dielectric properties were studied. A certain degree of phase mixing was observed to exist in all series as detected by the variation of the glass‐transition temperatures of the IPNs. Maxwell–Wagner–Sillars polarization at the interface of the two phases was observed. © 1994 John Wiley & Sons, Inc.
Synthesis and antibacterial activity of immobilized quaternary ammonium salts
Authors: Augusta S. , Gruber H. F. , Streichsbier F.
Published: April 2003

Quaternary ammonium salts were immobilized on hydrophilic gels based on sucrose methacrylates (SM) and tested for their antibacterial properties. The cross‐linked polymers were prepared by copolymerization of monomer–SM mixtures with 4‐vinylpyridine and subsequent quaternization with 1‐bromoctane and 1‐bromoctadecan and by esterification of SM gels with 3‐pyridine carboxylic acid chloride and quaternization. In addition, immobilized quaternary salts bonded by hydrophobic as well as by hydrophilic spacers were synthesized by esterification of SM gels with 11‐bromundecanoic acid chloride and the tetraethylene glycol‐based acid chloride 13c, respectively, and subsequent reaction of the halogen‐substituted gels with tertiary amines. Suspension tests for antibacterial properties of the immobilized bactericides against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus demonstrated high activity of the quaternary salts bonded by the hydrophobic spacer. Advantageously, these insoluble bactericides can be applicated without contamination of the substrate; they can be removed easily and used repeatedly. © 1994 John Wiley & Sons, Inc.
Investigation of polyamine quinones as hydrophobic curatives for epoxy resins
Authors: Rushing Rock A. , Thompson Corley , Cassidy Patrick E.
Published: April 2003

Polyamine quinones (PAQs), which have been used previously to produce solvent‐based coatings with exceptional durability in corrosive environments, were synthesized and blended with an aliphatic diamine (diethylenetriamine, DETA) to provide a liquid, epoxy curing agent. The PAQ–amine mixture was evaluated as a curing agent for an epoxy matrix resin system for glass‐reinforced composites. After elevated temperature water exposure, short‐beam shear and dynamic mechanical analyses were performed on the composites. The ability of PAQs to enhance fiber–resin bonding was evaluated. Dynamic mechanical analysis (DMA), which is a sensitive measurement of fiber‐resin interactions, showed that the PAQ curative enhances strength retention of composites exposed to aggressive environments. © 1994 John Wiley & Sons, Inc.
Use of neural networks for modeling of olefin polymerization in high pressure tubular reactors
Authors: Chan Wai‐Man , Nascimento Cláudio A. O.
Published: April 2003

Neural network computing is one of the fastest growing fields of artificial intelligence due to its ability to “learn” nonlinear relationships. This article presents the approach of back propagation neural networks for modeling of free radical polymerization in high pressure tubular reactors. Industrial data were used to train the network for prediction of the temperature profile along the reactor, as well as polymer properties such as density, melt flow index, and molecular weight averages. Comparisons were made between the neural network and mechanistic model predictions published in the literature. Results showed the promising capability of a neural network as an alternative approach to model polymeric systems. © 1994 John Wiley & Sons, Inc.
GPC and HPLC characterization of unsaturated polyester resins
Authors: Podzimek S̆. , Hyrs̆l J.
Published: April 2003

This article is concerned with the characterization of unsaturated polyester (UP) resins by conventional gel permeation chromatography (GPC), GPC connected with multiangle laser light scattering detector (GPC‐MALLS), and reversed‐phase high performance liquid chromatography (HPLC). The ability of particular methods to analyze UP resins is demonstrated in several examples. © 1994 John Wiley & Sons, Inc.
High‐performance semi‐interpenetrating polymer networks based on acetylene‐terminated sulfone. II. Phase separation and morphology
Authors: Mai Kancheng , Zeng Hanmin
Published: April 2003

The dynamic mechanical behavior, phase separation, and morphology of high‐performance semi‐interpenetrating polymer network (semi‐IPN) obtained from acetylene‐terminated sulfone (ATS‐C) and high‐performance thermoplastics have been studied by torsional braid analysis (TBA) and scanning electron microscopy (SEM). All the ATS‐C/thermoplastic blends studied are compatible before curing. The addition of ATS‐C results in a dramatic reduction in the glass transition temperature (Tg) of the thermoplastic. As the reaction of cure proceeds, the initially compatible blend passes through a stage of partial compatibility to achieve a fully incompatible semi‐IPN. SEM observation of the fracturedetched surface reveals the formation of a co‐continuous two‐phase structure in the semi‐IPNs. The connected globule and network morphology of the cured ATS‐C phase are dispersed in a matrix of the thermoplastic phase. The size of dispersed particles decreases with increasing Tg of the thermoplastic. The mechanism of phase separation is discussed. © 1994 John Wiley & Sons, Inc.
Synthesis and mesomorphic behavior of terminal oligo(ethylene glycol)monomethyl ether‐substituted low molecular weight thermotropic liquid crystals
Authors: Liaur Wen‐Bong , Ma Sun , Chang‐Chieh Guo‐Ping , Kuo Jen‐Feng
Published: April 2003

A number of alkenyl monomers containing biphenyl benzoate‐based on a mesogenic core with various lengths of oligo(ethylene glycol) monomethyl ether as the terminal group were synthesized. The purity, the thermotropic transition temperature, and the mesomorphic texture were investigated with 1H‐nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and optical polarized microscopy with a hot stage. The monomers studied in this project showed predominately nematic phases, whereas those with esterlinked derivatives studied in our previous work were able to present both nematic and smectic phases. They also exhibited higher isotropic transition temperatures than those of the ester‐linked derivatives. The factors governing mesophase texture and transition temperature are discussed thoroughly. © 1994 John Wiley & Sons, Inc.
Time‐resolved, pulsed laser sensitized acoustic technology: Application to on‐line sorting of waste plastics
Authors: Wan J. K. S. , Vepsäläinen K. P. , Ioffe M. S.
Published: April 2003

In industrial recycling of waste plastics the on‐line sorting of different kinds of consumer plastics often represents the key to the successful commercial operation. The principle and a limited feasibility study of a novel wavelength independent photoacoustic sensor applied to this problem are presented. This wavelength independent sensor offers the advantages of low cost, portability, and is not limited by the surface modifications such a color, printed labels, etc. in the commercial products. © 1994 John Wiley & Sons, Inc.
Polymer drying. IX. Effect of history on the kinetics of evaporation from poly(styrene‐co‐divinylbenzene)–liquid systems in the rubbery and glassy states
Authors: Errede L. A. , Henrich P. J. , Schroepfer J. N.
Published: April 2003

In these time studies of evaporation from liquid‐saturated microporous composite film samples, comprised of poly(styrene‐co‐divinylbenezene) particles enmeshed in poly(tetrafluoroethylene) microfibers, the samples were preswelled to saturation in a good solvent, such as toluene, which was then replaced via solvent exchange in excess test liquid before the start of the time study that monitored the residual weight (Wt) of sorbed liquid to virtual dryness. The patterns of change with time (i.e., Wt. vs. t and Log Wt vs. t) obtained thereby were compared with the corresponding time studies already reported for evaporation from equivalent polystyrene–liquid (PS–L) systems that did not have a history of preswelling in a better solvent. These comparisons show that the history of the samples in its liquid‐saturated gel state can affect markedly the kinetics of desorption from the PS–L system in its glassy state, and also during the interval of transition from the rubbery state to the glassy state, as discussed in the text. © 1994 John Wiley & Sons, Inc.
Studies on VOCl3/MgCl2/NaY/Al2Et3Cl3 complex support catalysts for the copolymerization of ethylene and propylene
Authors: Wang L. , Feng L. X. , Xu J. T. , Yang S. L.
Published: April 2003

Using VO2+ as a spin probe, a new method to obtain microenvironmental information on supports was developed which can be used in the choice of supports for coordination catalysts. Utilizing the above method, NaY was chosen as second support component. A complex support catalyst VOCl3/MgCl2/NaY/Al2Et3Cl3 was prepared and used in ethylene–propylene copolymerization. Higher polymerization activity was obtained with this catalytic system. Alternating the ratio of two kinds of supports, the composition and sequence structure of copolymers could be controlled, which showed that NaY participated in the active species, affected the insertion of monomer, and changed the composition and sequence structure of copolymers. © 1994 John Wiley & Sons, Inc.
Aqueous polymerization of methyl methacrylate initiated by redox pair: Ce(IV)–Azo compounds with methylol functional groups and synthesis of copolymers
Authors: Tunca U.
Published: April 2003

Hydroxyl functional azo compounds have been used as reducing agents in redox polymerization of methyl methacrylate (MMA) in conjuction with ceric ammonium nitrate (which acts as an oxidizing agent in aqueous nitric acid at 20°C). Kinetic measurements were followed by gravimetric method, at lower conversions, not exceeding 10% conversion. The dependence of rate of polymerization and average molecular weight, which was determined by gel permeation chromatography (GPC), on azo, Ce(IV), and MMA concentrations, respectively, were investigated. The homopolymers, which contain thermo‐and photolabile azo groups, were utilized with different comonomers to give block or graft copolymers depending on termination mechanism of homopolymerization. © 1994 John Wiley & Sons, Inc.
The effect of viscosity ratio on the phase inversion of polyamide 66/polypropylene blends
Authors: Hietaoja Pirjo T. , Holsti‐Miettinen Riitta M. , Seppälä Jukka V. , Ikkala Olli T.
Published: April 2003

The rheological properties of the blend components are an important parameter in the formation of a blend morphology. The effect of viscosity ratio on the morphology of polyamide 66/polypropylene blends was studied, with primary attention to the phase‐inversion behavior and the average particle size of the dispersed phase. The relationship between the mechanical properties and the phase‐inversion composition was investigated as well. Noncompatibilized and compatibilized blends having five different viscosity ratios were prepared by twin‐screw extrusion. Maleic anhydride‐grafted polypropylene was used as the compatibilizer to increase the adhesion between the two polymers and to stabilize the blend morphology. Investigation of the morphology of the blends by microscopy (SEM and TEM) showed that the smaller the viscosity ration (ηPA/ηPP) the smaller was the polyamide 66 concentration at which the phase inversion took place and that polyamide 66 became the continuous phase. The results are in accord with the model of Jordhamo. The compatibilizer induced a sharp reduction of particle size, but did not have a major effect on the phaseinversion point. The tensile and impact properties of the compatibilized blends were found to correlate with the phase inversion. An improvement in the mechanical properties was observed when polyamide 66 provided the matrix phase. © 1994 John Wiley & Sons, Inc.
Deformation behavior of polytetrafluoroethylene films under tensile stress at various temperatures
Authors: Yamaguchi Ken , Takachi Masayuki , Hirakawa Susumu
Published: April 2003

Deformation behavior of polytetrafluoroethylene (PTFE) films was investigated by thermomechanical analysis (TMA) under various tensile stresses (σ) up to 1.15 MPa in the temperature range from room temperature to 360°C. In the heating process above σ ≈ 0.25 MPa, a contraction of the PTFE film occurs in the melting temperature region. In the cooling process above σ ≈ 0.05 MPa, an elongation occurs in the crystallization temperature region, and above σ ≈ 0.5 MPa, it reaches 20–30% of the original length of the film. The PTFE films in the melt state above σ ≈ 0.5 MPa contract with increasing temperature up to 360°C and elongate with decreasing temperature. For the films that underwent deformation in the TMA, the crystalline orientation and the surface morphology were investigated by wide‐angle X‐ray diffraction and scanning electron microscopy, respectively. The degree of crystalline orientation in the deformed films increases with increasing σ and approaches a plateau at σ ≈ 0.4 MPa. On the surface of the deformed films, alignment of the bands and deformation of granules, which are formed by heat treatment above the melting point, are observed. © 1994 John Wiley & Sons, Inc.
Kinetics of glycolysis of poly(ethylene terephthalate) melts
Authors: Campanelli J. R. , Kamal M. R. , Cooper D. G.
Published: April 2003

The reaction of poly(ethylene terephthalate) (PET) melts with ethylene glycol was examined in a pressure reactor at temperatures above 245°C. The reaction rate was found to depend on temperature and on the concentrations of liquid ethylene glycol and of ethylene diester groups in the polymer. A kinetic model proposed for the initial period of the reaction was found to be consistent with experimental data. It was found that internal catalysis by ethylene glycol does not play an important role in the glycolytic depolymerization of PET. The rate constants for glycolysis were calculated for three different temperatures, yielding an activation energy of 92 kJ/mol. Zinc salts, which have a catalytic effect on glycolysis of PET below 245°C, do not appear to influence glycolysis rates above that temperature. © 1994 John Wiley & Sons, Inc.
Preparation of ultrafine metal particles supported on alumina by pyrolysis of polymer complex/alumina composites
Authors: Tamai Hisashi , Sakurai Hiroyuki , Yamagiri Takayuki , Nishiyama Fumitaka , Sakai Hiroshi , Yasuda Hajime
Published: April 2003

Ultrafine metal particles supported on alumina were prepared by pyrolysis of poly(vinylferrocene) (Poly(VFc))/alumina or sodium polyacrylate‐Pd(II) (Poly(AANa)‐Pd(II))/alumina precursors at 800 ∼ 1200°C. α‐Fe particles produced on k‐Al2O3 was obtained by pyrolysis of the mixture of Poly(VFc)/alumina(5/5) at 1000°C. Crystalline Pd supported on alumina was also obtained from Poly(AANa)‐Pd(II)/alumina precursor. The size of metal particles formed increased with increasing mixing ratio of polymer complex with alumina. © 1994 John Wiley & Sons, Inc.
Phase behavior of poly(ether urethane)‐nylon 6 block copolymer
Authors: Seo Seung Won , Ha Wan Shik
Published: April 2003

Poly(ether urethane) (PEU)‐Nylon 6 block copolymer film prepared via melt pressing and subsequent quenching in liquid nitrogen exhibited a one‐phase structure due to the specific interaction between urethane groups in the PEU block and the amide groups in Nylon 6 block through hydrogen bonding. Contrary to this, the solvent cast film showed a microphase separated structure which had risen from the poor solubility characteristics of the PEU block in the solvent. However, by heat treatment, the mutual miscibility of the block copolymer increased as a result of the hydrogen bonding formation. The block copolymer and Nylon 6 binary blend showed that these two polymers are compatible over the entire composition range mainly due to the specific interactions between the urethane and the amide groups in the blend through hydrogen bonding. The block copolymer in the ternary blend which consists of polyrethane (PU), Nylon 6, and the block copolymer prepared by melt extrusion was soluble in either of the PU and Nylon 6 homopolymers, inducing a homogenizing effect. © 1994 John Wiley & Sons, Inc.
pH effects on the solubility of polyacrylamides in hard brines
Authors: Albonico Paola , Lockhart Thomas P.
Published: April 2003

Solubility tests have been conducted on hydrolyzed polyacrylamide (PAAm) polymers to define the pH range for solubility as a function of the salinity of the solutions. These tests show for the first time that pH is a critical variable determining the solubility of extensively hydrolyzed PAAm in brines containing divalent cations. The pH range for solubility of PAAm and an acrylamide copolymer as a function of aging in synthetic seawater at elevated temperature is also reported. The underlying mechanisms for the pH‐dependent solubility behavior observed and the implications for petroleum applications of acrylamide polymers are discussed. © 1995 John Wiley & Sons, Inc.
Polymer networks based on the diepoxide–diisocyanate reaction catalyzed by tertiary amines
Authors: Galante María J. , Williams Roberto J. J.
Published: April 2003

Reactions taking place in a system consisting of a diepoxide (DGEBA, diglycidylether of bisphenol A) and a diisocyanate (TDI 80 : 20, toluene diisocyanate), catalyzed by a tertiary amine (BDMA, benzyldimethylamine), were followed by differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), and chemical titration of isocyanate groups in the pre‐gel stage. It was found that the main reactions took place in series, in steps of increasing temperature: (i) isocyanurate formation, (ii) epoxy‐isocyanate reaction leading to oxazolidone rings, and (iii) isocyanurate decomposition by epoxy groups producing oxazolidone rings. Isocyanurate rings were stable in the presence of epoxides and an isocyanate excess [reaction (ii) was faster than (iii)]. Epoxy homopolymerization (secondary reaction) occurred in parallel with steps (ii) and (iii). Step (i) took place by two different mechanisms and led to a maximum conversion, possibly limited by topological restrictions. A kinetic study of TDI trimerization in the presence of an equimolar amount of DGEBA and variable amounts of BDMA led to a third‐order regression with an activation energy E = 43 kJ/mol. © 1995 John Wiley & Sons, Inc.
Morphologies of poly(vinylcarbazole)–polyisoprene graft copolymer and blend
Authors: Ishikawa Satoshi
Published: April 2003

The microstructures of a poly(vinylcarbazole‐g‐isoprene) and blend of poly(vinylcarbazole) (PVCz) and polyisoprene (PIP) were studied by transmission electron microscopy (TEM). In the graft copolymer, the unique microphase separated structure was observed. In the blend, the blend ratio did not correspond to the area ratio on the TEM photograph. It is suggested that the results are caused by rigid and crystalline PVCz and low glass‐transition temperature of PIP. © 1995 John Wiley & Sons, Inc.
Mechanical behavior of particulate composites: Experiments and micromechanical predictions
Authors: Wong F. C. , Ait‐Kadi A.
Published: April 2003

A model, based on linear elasticity and the first law of thermodynamics, was evaluated using experimentally derived data to verify its predictive capabilities. The model demonstrated that it could correctly predict the mechanical behavior of highly loaded composites if a representative adhesion energy was available. It worked well for systems where material nonlinearity was mainly due to particle debonding. The model could not, however, account for the effects of localized straining or stress concentrations on composite modulus or strength. In systems where matrix nonlinearity dominated, predictinos were less satisfactory. Although the model oversimplified the debonding process, it provided a convenient mechanism for relating the composite modulus and stress–strain state to the loss of reinforcement without requiring a micromechanical description that was too cumbersome to manage. Nevertheless, the inability of the model to account for localized strains, stress concentrations, and matrix nonlinearity needs to be addressed in order to obtain better mechanical behavior predictions. © 1995 John Wiley & Sons, Inc.
Graft copolymerization of dimethylacrylamide onto AFLAS
Authors: Lopez Rafael , Sanchez Victor , Fucugauchi Luz Alicia , Otsuhata Kazushige
Published: April 2003

The method of irradiation grafting of DMAA onto AFLAS (alternating copolymer of tetrafluoroethylene and propylene) films was studied. The effect of the solvent on the grafting yield was determined. As a result, it might be important to evaluate the blood compatibility of the films already grafted by using an in vitro test. Benzene tests seem to be the most adequate for copolymerization. Grafting yield was better in the monomer 40–60% concentration range. The degree of grafting increases proportionally to does rate in gamma ray radiation. The graft copolymerization is terminated via unimolecular mechanism. © 1995 John Wiley & Sons, Inc.
Effects of poly(vinyl acetate) and poly(methyl methacrylate) low‐profile additives on the curing of unsaturated polyester resins. II. Morphological changes during cure
Authors: Huang Yan‐Jyi , Su Chin‐Cheng
Published: April 2003

The effects of two low‐profile additives (LPA), poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA), on the morphological changes during the cure of unsaturated polyester (UP) resins at 110°C were investigated by an approach of integrated reaction kinetics‐morphology‐phase separation measurements by using a differential scanning calorimeter (DSC), scanning electron microscopy (SEM), optical microscopy (OM), and a low‐angle laser light‐scattering appartus (LALLS). For the UP resins cured at 110°C, adding LPA could facilitate the phase separation between LPA and crosslinked UP phases early in the reaction, and discrete microgel particles were thus allowed to be identified throughout the reaction. Microvoids and microcracks responsible for the volume shrinkage control could also be observed evidently at the later stage of reaction under SEM. Depending on the types of LPA and the initial molar ratios of styrene to polyester CC bonds, the morphological changes during the cure varied considerably. The progress of microstructure formation during reaction has been presented. Static ternary phase characteristics for the styrene–UP–LPA system at 25°C have also been employed to elucidate the resulting morphology during the cure in both the continuous and the dispersed phases. © 1995 John Wiley & Sons, Inc.
Assimilation of oil from metal surfaces by epoxy adhesives: XPS and ATR analyses
Authors: Hong S. G. , Boerio F. J.
Published: April 2003

The oil displaceing and absorbing behaviors of epoxy adhesives cured with amidoamine curing agents on oiled metal substrates were studied using X‐ray photoelectron spectroscopy (XPS) and attenuated total reflection infrared spectroscopy (ATR). A Simple XPS experiment demonstrated that amidoamine curing agents could displace an aliphatic oil from the cold‐rolled steel (CRS) and the electrogalvanized steel (EGS) surfaces, but an epoxy resin based on bisphenol A could not. Results of ATR measurements sowed that the oil was effectively displaced from the CRS surface and absorbed as deep as 2 μm into the epoxy adhesive cured with amidoamine with low amine numbers. But the oil was mostly present in the 0.3 μm thick adhesive layer near the CRS/adhesive interface for the epoxy adhesive cured with amidoamine with high amine numbers. The oil absorbing ability of the adhesive was worse on the oiled EGS substrate than on the oiled CRS substrate. It was also found that the pressure applied during cure could greatly facilitate the absorption of oil into the adhesive. © 1995 John Wiley & Sons, Inc.
Anomalous diffusion of iodine ions into polypropylene implanted with F+ and I+ ions
Authors: Hnatowicz Vladimír , Kvítek J. , S̆vorc̆ík Václav , Rybka Vladimír , Popok Vladimír
Published: April 2003

The diffusion of K and I atoms from 5 M water solution of KI into polypropylene implanted with 150 keV F+ and I+ was studied at boiling temperature. Standard Rutherford back scattering (RSB) technique was used for the determination of concentration depth profiles of diffused atoms. It was found that the I and K atoms penetrate the polymer surface layer affected by ion implantation and they are captured by trapping centers produced by electronic energy losses of implanted ions. The uptake of K atoms is several times higher than that of I atoms, and the relative K concentration exceeds the KI stoichiometric value. © 1995 John Wiley & Sons, Inc.